Botany of Breadmaking

When talking about bread, we are discussing plant products: wheat flour, sugar, yeast, and cooking oil plus salt and water. The information presented here is both botanical context to breadmaking, as well as points to discuss during the crucial activity, working with students to make what is likely their first loaf of yeast-risen bread (see instructions), as well as a pizza dough. Either activity is a good place to begin. Regardless as to what kind of bread we make, the miracle substance is flour, which millers manufacture by pulverizing millions of grains of wheat (ignoring for a momentthe many other kinds of flours). In the culinary world, those grains, or kernels (technically each is a “caryopsis”), are called called “wheatberries”.

Wheat Flour – Background Botanical Context. All agricultural “grains” are the seed of grasses, which means they are members of the well-circumscribed Grass Family, the Poaceae. Seed such as Buckwheat and Quinoa, though used in many ways similar to grains, are sometimes called “pseudocereals” because they are not produced by grasses and lack the qualities and characteristics of grains.

We call the Grass family the Poaceae because plant families names are based on one of the included groups (genera), in this case the genus Poa, a word that comes to us from the Greek term for field plants grazed on by animals (fodder). Many people will be familiar with the common herb Poa annua, also called Meadow Grass, which is one of many kinds of grassses planted for lawns. But the Grass family is extensive, including the edible grains (wheat, rice, corn, rye, barley, oats, millet) as well aa other food and fiber plants, most significantly sugar cane and bamboo. These plants all make the same kind of fruit, a grain, also called a kernel (botanically, a caryopsis.) The seeming proliferation of terms may seem redundant, but grains have been so important to civilization that many specific terms have emerged in describing their fascinating and particular structure. That structure and character yield abundant carbohydrates that make grains so absolutely critical as food sources.

Humans have harvested and cultivated grains for thousands of years. Wheat farming and selection, specifically, stretches back over ten millennia; it’s a valuable starch-rich food source that can be harvested, stored, shipped, traded, plundered, taxed, and utilized to make a wide range of foods.

Wheat flour is magic. You can dismantle the grain in different ways, add water, and make remarkable edibles, such as porridge and bread or beverages, like beer. The grain and plant can be fed to livestock. Dried stems have been used for bedding and construction. Most people will appreciate that wheat, along with rice and maiz (corn to Americans) are basic to human nutrition. Those and many other grains (oats, barler, rye, milo) link to major settlement and civilization around the globe. Today, wheat cultivation covers the most acreage of any food crop.

People generally, even professional bakers who work with wheat, are not too concerned with its anatomy, which means that popular culinary books sometimes provide nebulous details about wheatberries, leading to misguided assumptions. Moreover, focusing on the wheatberry serves as a useful model to understand all grains, and thus some of the science behind our food chain.

Wheat and rice flowers are perfect, which means each flower has both pistils (female, fruit-producing parts) as well as anthers (the male, pollen-producing structures.) Maiz, on the other hand, separates the sexes; staminate (male) flowers form in tassels at the tip of the stem, while pistillate (female) flowers develop in “ears” tucked into leaf axils along the stalk.

As with all grains, the wheatberry fruit wall is sealed to the seed coat (the testa). As long as a kernel hasn’t been cooked or killed, you can germinate a new wheat plant in just a few days. In fact, the grain will germinate on any wet surface, like a paper towel or spongy mat, which is the reason you can purchase the plants as “wheat grass” at various kinds of stores, sold for juicing into smoothies as well as grazing treats for cats.

Germinating wheat seed provide crucial visual comparisons for students who are examining the structure of dry kernels, even more useful if hand lenses or dissection microscopes are available. Wheat seed grown to maturity will flower and fruit. Unlike modern maiz, wheat (like most grasses) will not remain a single stalk, rather new side stems (called tillers in the wheat world) will emerge from leaf axils at the base of the plant. Sometimes these side branches are strong enough to produce “ears” – which is the common term for the clusters of flowers and fruit (inflorescences, then infructescences) that terminate stems. Those ears (botanically they are spikes) characteristically form made rows of “spikelets.” Each spikelet is a side branch that produces small flowers, possibly several. The more basal flowers will successfully generate kernels.

Grass flowers differ enough from those of other plants so as to require particular terminology and demand their own cadre of specialists. You’ll not hear grass scientists describing sepals and petals, rather they are absorbed in describing special bracts – the glume (which subtends each spikelet), the outer lemma and inner palea that enclose a flower, and the two lodicules that surround each flower’s three anthers and pistil (the ovary). We’ll not belabor these structures beyond explaining these parts are not mere decorations; they actually have useful roles.

The lemma and palea clam-shell to protect a flower’s anthers and ovary. At flowering, they are forced open by swelling of the knobby lodicules. Flowering (anthesis) is brief, with spreading of the enclosing lemma and palea lasting only about an hour. During that short exposure, the anther filaments and pistil styles expand quickly (in less than 5 minutes), pollen is shed, and pollination occurs. Wheat pollen is short-lived, viable only a few hours and germinating as soon as it lands on a stigma. Germination yiels a pollen tube and achieving double fertilization within two hours.

Who Knew? I know things became incredibly complicated, but we do not have to go deeper into the process, and you, therefore, are welcome to ignore the next two paragraphs,. It’s technical stuff. but we just arrived at the greatest and most essential mystery about flowering plants, and grains specifically. Not only did I just introduce a slew of new technical terms, I also said something few people realize or appreciate – “double fertilization.” In general, botanists shield the public from this significant miracle, avoiding discussing a complex sequence of events that sets flowering plants apart from the cone-bearing gymnosperms. But with grains, double fertilization is the salient difference. Pollen grains of flowering plants have two sperm nuclei, each of which marries to different nuclei in the ovary (i.e. in the “egg sac”.) This isn’t like twins in humans at all; the two sperm nuclei have distinct fates. One procreates; it will unite with the egg, creating a zygote, the first nucleus of an embryo, a new plant. The other sperm nucleus unites with a pair of nuclei hanging out in the egg sac, away from the egg; we call those the polar nuclei, and together the new nucleus (now triploid, with three sets of chromosomes) heads up a cell that multiplies aggressively, creating a triploid (3 sets of chromosomes) starchy tissue called the endosperm high.

The endosperm remains completely inside and constitutes over 80% the seed, where it serves as nutritive tissue for embryo germination. Most flowering plants follow this initial pattern, creating an embryonic nucleus and an endosperm nucleus. In some plant groups, such as beans, the endosperm never develops substantially. But in other important groups, notably monocots, like grains and palms, the endosperm bulks up, constituting most of the seed mass and providing the seed’s major energy reserve for germination. At maturity, therefore, a wheat kernel is complex – it is a 1-seeded fruit with a small embryo pushed to the side by a much larger mass of storage tissue, the endosperm.

The View from Food Science: To the food scientist, a wheat kernel is simpler; it has three useful zones: bran, endosperm, and germ. 1. Bran: Examining a kernel of wheat, the tan-colored exterior is the fruit wall (the pericarp), which is melded to the next internal layer, the seed coat (the testa.) These protective layers have little nutritive value. During milling, they are typically chipped off, along with the outer endosperm layer (the aleurone cells) – the three layers are constituting the bran. Nutritionists consider bran a kind of “fiber” – which is their way of saying it provides useful ruffage in diets. (Botanists have a completely different use for the word fiber, so don’t get confused when you run into fiber cells in a different context.) 2. Endosperm: The creamy-white endosperm that constitutes the bulk of the wheat kernel is what we grind (mill) into white flour, i.e. unbleached flour. Customers who don’t like a yellowish color to their flour may prefer the bleached version that was brominated in order to break down residual color (aging accomplishes the same whitening). The triploid endosperm cells are packed with starch grains (botanists call these plastids), varyingly rich in protein, depending on the strain and growing conditions. Cells that make up the creamy-colored inner endosperm die when mature, constituting pure food storage, which means most cells in a mature wheat kernel are dead. The only living cell layer was the aleurone, which generates enzymes that break down starches to sugars that nourish the germinating seedling. 3. Germ: On examining an intact kernel, you’ll see a crease runs from the bearded (bristly) rounded tip to its blunt base, where the grain was attached to the stem. The germ (embryo) forms inside that base, usually detectable as a small protrusion. In milling white flour, the germ is broken off and collected separately. Rich in oils with a buttery taste, wheat germ is sold in sealed containers to avoid exposure to air, which can cause the oils to turn rancid. Those oils are also a reason whole wheat flours (which include bran and germ along with the endosperm) have less shelf-life than white flours. Many people store flour, especially whole wheat flour, in the refrigerator or freezer. As long as a stored grain is viable (which can be many years), cells in the germ (the embryo) and the aleurone are alive and able to spring into action when water and the right growing conditions are provided. Additional to activity of the aleurone layer, the embryo generates enzymes (amylases) that break down the starches, proteins, and other cellular components of the endosperm to generate sugars.

Kinds of Wheat Flour. Bran, endosperm, and germ characterize all wheats, but there are many different wheat flours available, depending on the kind of wheat (which strain) is used and which “streams” the miller includes in the final product.

Hard vs. Soft Wheat. Different kinds (strains, cultivars) of wheat are particular to different growing regions, yielding predictably characteristic flours. Most simply, we think of hard wheat and soft wheat flours. Hard grains have higher protein content (as much as 14-15% by weight) while soft grains can have less than half that amount. The harder wheats are used in making pastas and chewy breads. Semolinas, the hardest of wheats, are particularly useful in pasta-making and will often be milled to a fine grit, not even to powder. Soft wheat flours are prized for tender breads, such as cakes and biscuits. The common flour in most kitchens is all-purpose (AP) flour, a blend of hard and soft wheat flours. This should aprise you that different mills will produce distinctive versions of common AP flours and explains why cooks and bakers tend to stick with brands of flour they know from experience.

Milling. Modern mills use complex sequences of high speed steel rollers to break down grains, chipping or grinding them so different components and grit of graded sizes are separated into “streams” – such as bran, germ, coarse flours, and fine flours. Streams are recombined to generate various flours, such as whole wheat (which implies a proportioned dose from each stream). Traditional gristmills (stone mills) still operate, feeding grains (grist) into paired upper and lower stones while the upper runner stone is turned, producing stone-ground whole wheat flours. That flour can be “bolted” (sifted through grades of cloth) to make a whiter product free of bran and germ. Stone-ground flours are preferred by many bakers because the slow speed avoids heating the wheat (high speed rollers generate high temperatures). On the other hand, those older flours will naturally include some pulverized stone. Prior to modern milling, people whose diets were based heavily on breads experienced serious tooth wear. We recall from grade school that elephants also wear down their molars, but an elephant has spare tooth buds (at least 6 sets) that will erupt to replace worn dentures.

How Flour Becomes Bread. Once flour is incorporated into a dough or batter, the starch granules are suspended in a matrix of moistened proteins and other materials. The proteins give elasticity to the dough, which when properly developed allows gases to be trapped, forming tiny bubbles that (like foam products) can inflate the dough to form a structure in which countless starch granules (plastids) are suspended. At normal ambient temperatures, starch molecules are semi-crystalline and densely packed, and the plastids are reasonably resilient to breakdown in water. But with added heat, water penetrates the plastid membranes and enters the solid granules of starch, which then breakdown to form a paste, a thick gel.

Depending on the kind of wheat and pH of the water, the disassembly and dissolution of the starch molecules takes place at 55 – 85 ºC (131 – 185 ºF).; we call this gelatinization. The expanded starch molecules now trap water, forming a gel, which takes on the qualities of an adhesive as it dries Hence we make pastes for crafts and wall paper from cooked flour, and we stiffen clothes by ironing starch into the fabric.

The Crumb. This is the process observed when cooking breads. By the time bread reaches an internal temperature above 85 ºC (185 ºF), the proteins have coagulated and the starches have gelatinized. That means the bread crumb is cooked and will cool and set with a moist, airy internal texture. In pizza and other flatbreads that are mostly about the crust, the freshly-cooked product is ready to eat, so get it while it’s hot.

With loaf breads, caution must be given. While the bread is still hot, the starches have gelatinized but not set (think of boxed pudding that is thick when hot, becoming semi-solid when chilled). Cutting into a loaf fresh from the oven can make for wonderful eating, but also will likely collapse the structure, because the gelatinous walls of starches and proteins lose their fragile inflation and fold in on themselves. This also explains why freshness of breads is short-lived. Once starches and proteins set, they begin to loose water content. Their springy, moist crumb hardens, and the starches begin to recrystallize (this is called starch retrogradation), which is the major factor in what we describes as “stale” bread. This is the reason you are advised to moisten bread before reheating; applying water vapor to the starch restores some of its gelatinization and consequent softer texture.

The Crust is about browning and a bit of charring. Browning relates to two major processes, the Maillard reaction and caramelization. In studying protein synthesis, Louis-Camille Maillard described protein browning in 1912. Much of the color and taste of crust develops from 140 to 165 °C (280 to 330 °F), as heat affects the nature of proteins and their constituent amino acids. Caramelization is different; that’s the browning (burning) of sugars, and occurs at a range of temperatures, depending on the kind of sugar present. Fructose begins to brown at 110 °C (230 °F), Galactose at 160 °C (320 °F), Glucose and Sucrose at 160 °C (320 °F), and Maltose at 180 °C (360 °F). It should not be surprising, therefore, that fruit dishes (which are high in fructose) burn easily.

When we place raw bread in hot ovens, especially bread ovens, we initiate a complex set of physical and chemical reactions. With flatbreads, the goal is to retain some freshness in the crumb of thicker areas while driving the crust to thin crispness, crustier than a tortilla but short of a cracker. This is the moment the way the dough was stretched and relaxed reacts to the hot oven (which for pizzas can range between 550 and 650 ºF on the floor and 800+ ºF in the dome), the humidity surrounding the bread (moisture can retard hardening of the crust and allow greater “oven spring” or “bloom”), the composition and thickness of amendments and toppings, and the flavors derived from the wood fire (if available) to create bread superior to a packaged commercial loaf or a pizza unlike anything delivered in a cardboard box or cranked out of a toaster oven.

Flours from other Grains. A wide range of grains and even other dried starchy materials (such as potatoes) can be made into flour. They are all predominantly starch grains, but differ from wheat in the the amount and kind of proteins in the grain. Wheat has always been important for bread making because the balance of proteins (glutens, principally the glutenins and gliadins) is just right for giving elasticity to doughs. Proteins present in flours from other grains, rye, barley, oats, corn, and rice, do not have the same qualities. Wheat flour alone supports doughs that rise nicely and yield a nice crumb when cooked. Of course, for those with gluten allergies, it’s these very gluten proteins that create problems in digestion.

More Botany – Details on the Wheat Kernel. In the event it is useful to understand more about the way agronomists (botanists who study grasses) talk about wheat kernels. Here is that more elaborated story. Over 50% of human caloric consumption is based on food energy stored in wheat, rice, and maiz grains, used as edible whole grains, production of starches and flours, extracted for syrups, and processed for fats & oils. Wheat, particularly, is grown for flour, pulverized 3n (triploid) tissue, the endosperm, which constitutes the bulk of the grain. Once a wheat grain is fully mature, the seed sets into dormancy, a period of near-suspended animation that can last many years – until water is provided and conditions are right for germination.

The organization and layering of this dormant wheat seed (a one-seeded ovary) is astonishing. Holding a grain (also called a kernel or a berry) in your hand is like holding a small pellet. With greater inspection you’ll discern it isn’t spherical, rather the kernel has a rounded base and a more dome-shaped tip, decorated with short brush of hairs, sometimes called the “beard.” From base to beard there is a cleft, much like the crease you see in a peach. That is not surprising in that many fruit show one or more sutures that remind us the fruit wall seals around the seed. Creamy-tan to brown in color, when cracked open, the light yellow core, the endosperm, obviously makes up the bulk. But breaking into the grain, you’ve ruptured thin yet very different layers. The outer, darker layer is not the seed coat. Since a grain is a 1-seeded fruit, technically the outer layer is the fruit wall (the pericarp), which bonds completely to internal layers we regard as the outer coating of the single seed (the testa). The seed coat covers the endosperm, which makes up the bulk of the kernel. Except for its outer layer of cells, the aleurone tissue, endosperm cells are dead at maturity. At the base of the grain, where it was attached to the stem, you’ll find the embryo, which processors call wheat germ. The embryo has a well-formed shoot tip, root tips, and a shield-shaped intermediate structure called the scutellum. In breaking through the kernel, you’ve encountered cells with three different genetic makeups. The embryo, of course, has the diploid genetics of the new plant. The endosperm is a curious tissue made in the seed of flowering plants but most prominent in monocots, like palms and grasses. The seed coat and fruit coat are tissue made by cells of the parent plant, and thus have the diploid genetics of the parent. In highly selected wheat strains, the genetics of the parent stock will be the same as the new seed crop. When a wheat kernel germinates, embryonic roots already present in the germ emerge first, a day or two before the shoot appears. Root establishment is crucial; not only do roots bring in water and nutrients, the mass of prop roots emerging from the stem base makes a “root-soil plate,” basically a stand that helps keep the plant upright. Things go wrong in a wheat field when the plants “lodge” – that is, when they fall over, having being trodden or wind blown. In addition to its primary roots, the embryo (the germ) has two other parts, the growing shoot and the scutellum, a tiny shield-shaped structure formed between the shoot and root. The shoot, of course, makes leaf and stem, pushing upward from its central growing point. The first structure to emerge and turn green is a tubular leaf called the coleoptile. Yes, it is tubular, as are all future grass leaves when first formed. And this tubular coleoptile surrounds the growing tips, which presents a conundrum. All future leaves, as well as the stem growing tip have to push through the tubular coleoptile. To get your head around this, think of a wheat plant (in fact, all of the grains and most other monocots like onions and palms) as telescoping. The growing tip is constantly producing new leaves from the center, which means the bases of older leaves have to give, spread out, providing space and sheathing the newer arrivals. This is one reason it’s worthwhile to examine germinated (or purchased) wheat grass, the monocot growth pattern is difficult to understand otherwise. Among the seedlings students will see each embryo casting out roots and sending up its coleoptile, with succeeding leaves beginning to push through the tubular coleoptile tip. They’ll note brown outer grain layers (the pericarp and seed coat) remain attached, though these components have become thin and hollow, as the endosperm filling them ws utilized by the growing seedling. Botanists say the embryo has “mobilized” the stored starch. This mobilization happens quickly, as the roots and shoot sprout in just a few days. To recover the sugars, which were stashed away as starch in the endosperm cells, enzymes present in the aleurone layer and scutellum are released when seed take on moisture. Some of the enzymes dismantle cellulose walls, while others, amylases, break down complex amylose (the term for plant starches) into sugars which can be translocated (shipped through cells) to be used for energy and components. Humans learned to take advantage of this germination stage as a way to harvest amylases for beer and whiskey making. You can malt wheat seed, but malting is a big business and barley is a better source of the needed enzymes. To generate the needed enzymes, brewers typically germinate huge quantities of barley seed that are still in their husks (which gives added protection to the embryo, often called the acrospire by brewers). They halt germination as soon as the coleoptiles have emerged, drying the seedlings with gentle heat. The malted barley can be fermented for beers and whiskeys, or in a pulverized form, the enzyme-rich malt is used by brewers to break down starches in grains (and even potatoes and other starchy products) used for fermentation, as well as by bakers to promote starch breakdown during breadmaking.

How do Glutens (proteins) affect Doughs made fromWheat Flour? Reviewing earlier comments, wheat kernels are harvested through threshing the heads of wheat (which breaks the grains away from the straw) and winnowing (removing chaff, the bracts that surround the wheat kernels). The kernels can be ground to flour. Using every part of the kernel produces whole wheat flour. Breaking away the bran (pericarp, testa, and aleurone) and the germ (the embryo) leaves creamy endosperm that is milled to make white flour.

Why do I say “hard” in relation to flour? It has to do with protein content, and the kinds of proteins one finds in wheat. Recall the endosperm is rich in starch (80-90%). Proteins are also present, and they strengthen the grain, actually making it harder to crush or mill. Low-protein flours are powder-like (soft-textured), while higher-protein flours can be granular, even gritty (hard). For bakers, soft and hard translate directly to breads. Using soft wheats, those with lower gluten content (around 6%), turns out softer, less chewy breads, while hard wheats can give strong pastas and springy, chewy, heavily textured boules. Mixing hard and soft flours for one blend yields all-purpose flour (which cooks call AP flour).

Ground into flour, it is easy to imagine wheat endosperm as a simple mass of starch with varying amounts of protein. But neither the starch nor the proteins are stashed away as simple masses. Like all plant parts, endosperm is cellular – cells that produce and manage the entire range of molecules they require: carbohydrates (sugars, cellulose, starches), proteins, nucleic acids, lipids (fats and oils), steroids and terpenes, etc. Those components are well-organized and positioned within each cell. Starch is produced and stored in cellular structures (organelles) called plastids.

A Deep Dive into Starch Plastids (Amyloplasts). You’ll not hear much about plastids because cells of humans and other animals don’t have them, but the several kinds of plastids are amazing components of plant cells. They are like subcontractors, aliens, somewhat independent, while still working for and housed by their clients, the cells. The plastids have their own management system (their own DNA) and reproduce independently. Moreover, they take on particular jobs, and are sometimes conveniently color-coded. Green plastids (chloroplasts), for example, are sites of photosynthesis, filled with highly-defined layered structure that form networks of chlorophyll. Carotenes are produced and sequestered in orange and yellow plastids called chromoplasts. Clear plastids will contain either oil or starch, the starchy ones we call amyloplasts or simply, starch plastids; oily plastids are called elaioplasts.

Yet more astonishing, plastids are chameleon-like multi-taskers. A chloroplast might generate starch, turning from green to clear, so it morphs into an amyloplast. Scientists are well-convinced that plastids evolved as separate photosynthetic life forms that were taken in by plant-like organisms. We call such arrangements “symbiotic” – something that benefits both biological beings. A more woke interpretation would be enslavement. Plastids work for the company store, the cell. As the endosperm develops and the grain matures, tens of thousands of cells form, each cell filled with starch plastids. By the time development of the kernel is complete, endosperm cells (except the outer aleurone layer of cells) undergo PCD (Programmed Cell Death).

Kinds of Plastids botanists have described include:

• Chloroplasts: green plastids for photosynthesis; see also etioplasts, the predecessors of chloroplasts
• Chromoplasts: colored plastids for pigment synthesis and storage
• Gerontoplasts: control the dismantling of the photosynthetic apparatus during plant senescence
• Leucoplasts: colorless plastids for monoterpene synthesis; leucoplasts sometimes differentiate into more specialized plastids:
  • Amyloplasts: for starch storage, involved in detecting gravity (for geotropism)
  • Elaioplasts: for storing fat
  • Proteinoplasts: for storing and modifying protein
  • Tannosomes: for synthesizing and producing tannins and polyphenols

Summary: A wheat kernel (the berry) is a single-seeded fruit, the mature pistil from a wheat flower. As a fruit, its outer tan layers are pericarp (a thin fruit wall). The pericarp is seamlessly bonded to the testa (the seed coat). In making flour, those are broken off and (along with the outer endosperm, the aleurone layer) constitute bran.

At the base, along the side of the grain is the small but vital embryo, the germ. This is chipped off and sold separately as wheat germ.

What remains is endosperm, which is also somewhat layered. Making up the outer layer, any remaining aleurone cells are living, starch-loaded crucial players in germination. The great majority of starch-filled endosperm cells die at maturity. PCD (programmed cellular death) is a way of life for these storage cells, which don’t have to be alive to serve their purpose as a food reserve for the germinating grain. We mill (grind) t endosperm cells to make white flour. (Paola Tosi, et al, 2011)

Packed with starch, endosperm cells also contain protein. Though the starches are corralled by plastids, wheat protein is made and stored throughout the cell itself, generated at cellular membranes specializing in protein production (the endoplasmic reticulum). Proteins either hang out around those membranes, or they may be translocated to the cell’s central vacuole.

The proteins most significant to breadmaking are called glutens, the very glutens that create problems for people who suffer from celiac disease. The combination of springy and slippery proteins that make up glutens (glutenins and gliadins respectively) confer elasticity that makes wheat flour perfect for chewy, strongly textured breads, most especially the “hard” high gluten flours with 10-14% protein. When teaching breadmaking classes or pizza making, you’ll always need to determine whether any participants have gluten allergies. They’ll be able to make the breads, but should be careful in tasting or consuming the final products.

Lab Experience: You can readily show students starch granules using fresh potatoes. Make a microscope slide wet mount using as thin a potato slice as possible. Using the 40x lens (therefore, a total magnification of 400x), you’ll readily see individual cells that are packed with starch granules, but cell walls and the plastids have no color, so adding a drop of iodine at the edge of the cover slip slowly penetrates the potato, staining the starch nearly black. This provides a spectacular demonstration; students easily will see clear cells packed with blue-black starch grains. Though starchy cells in potato are formed in the tuber (stem) cells, they are similar to those you’d see in wheat endosperm… For comparison, stain a bit of flour on a wet mount, and you’ll see the comparable wheat granules.

ACTIVITY: How I teach a Breadmaking novice – using a Sandwich loaf

Hands-On Breadmaking is a great opportunity to explore plants, chemistry, and food. I will lay this out for you just as I go through it with small groups. Let’s start with the simplest recipe and process, the single-loaf process. For a class, using the following materials: 

• a work surface (a kitchen counter is fine, but if available, I like to use extra large cafeteria trays, called market trays)
• a simple measuring cup and teaspoons
• a small loaf pan
• an oven (hot pads, etc.)
• a cloth (I like the the ones called “flour sack towels” available from many supply houses
• a dough scraper (plastic may be better with students) 
• wooden paddles such as you’d use for popsicles, for identification of a student’s loaf

Additionally, the following supplies are recommended: 

• whole grains of wheat (wheat berries)
• wheat sprouts (purchased, or germinated on a moist paper towel)
• gluten (powdered)
• a bottle of wheat germ (still sealed) 

For Breadmaking, you’ll need small carry sacks (for take-home bread), a printed recipe (also to take home), and the following ingredients: 

• bread flour (3-4 cups for each participant)
• instant (rapid rise) yeast (1 Tablespoon per participant)
• sugar (1 Tablespoon per participant)
• salt (1 teaspoon per participant)
• hot water (1 to 1.25 cups)
• olive oil (1 Tablespoon for the recipe, and additional for coating the tray and hands)
• a can of spray oil with flour (baker’s release spray) 

The Experience of Making Bread: It is useful to jump right into the process of making bread, in that you can consider other lessons while the bread rises….. After a communal washing of hands, I ask each person to pour a bit of olive oil in his/her palm, and use that to coat both hands and work surface.

Then, we: 

1. Measure 3 cups bread flour onto the work surface.

2. Combine 1 T instant yeast, 1 T sugar, and 1 t salt with the flour, setting a portion (about 1/3 cup) of the mixture off to the side.

3. Using hands (or the bottom of the measuring cup), students shape the remaining flour mixture into an atoll – a donut-shaped mound(the reef) – the center of which (the lagoon) will be filled gently with a cup of hot water. 

4. Bit by bit, using their fingers (sort of limply hanging into the water), ask students to dredge in flour, so as to make a slurry – attempting to keep the water from escaping the 
flour dam that was the atoll…. 

5. Once there is no free water, the new breadmakers will pour 1 T of olive oil over the mixture, and proceed to create a dough that includes all of the flour and water. 

6. Students should take a moment to consider the dough. If it is stiff like modeling clay, you will need to incorporate more water. If it flows or settles of its own accord, you need more flour. The dough should be soft but cling together as a mass. As you work the dough, add flour only if it remains wet and tacky – do not follow the temptation to add so much flour as to make it stiff. A soft dough is preferable to a stiff one. 

7. For the beginner, I teach kneading by the roll method. Gather the dough into a long, fat rod-shape, turn it so the rod runs straight away from you. Lightly (a dusting) flour your hands and the work surface, then tightly roll up the rod, like you are rolling up a ribbon. 

8. Now, using your palms, roll the the ball back and forth until you once again have a rod several inches long. Repeat the rod and roll procedure to make a tight ball into a rod, and so on – until your dough ball has some elasticity.

9. At this point, you can stretch the dough and it will maintain its surface, showing small blister-like inconsistencies in the surface. Moreover, your hands should be clean. If the moisture is right, your dough does not cling in patches to the work surface, and does not stick to your hands.

10. Time to let it rise. I ask students to pour a dabble of olive oil in their palms and use that to coat the dough ball. Set it on the work surface and cover with the cloth. 

Points to be made in Discussion with Students: Forget the dough for a while. Let’s consider wheat, flour, and the botanical nature of what we are doing. Have students inspect a wheat kernel (“berry”). It is slightly cleft, not as smooth as a grain of rice, but very similar. Not surprising; wheat (like rice, barley, oats, rye, and corn) is the fruit of a grass. These are grains, and they power our world.

I said fruit, which is precisely what I meant. A grain (kernel) is a single-seeded fruit – each was the pistil of a flower, which was one of several on the plant stem (culm). The grains differ from most other seed by investing starch storage in a curious tissue called endosperm. The endosperm was formed at the same time the egg was fertilized, and it grew courtesy of nourishment from the parent plant. At the same time endosperm was bulking up, the embryo developed. So inside the grain there is an embryo (which we call the “germ”) that is dwarfed by a separate, starchy endosperm component. You will not be able to see this in the wheat kernel, because both the endosperm and germ are hidden inside the tan fruit wall, which botanists call a pericarp and most other people call “bran.”

If you grind (mill) a bunch of these wheat berries (raw), you’ll have whole wheat flour. If that were accomplished using an old-fashioned grindstone, you’d have “stone ground whole wheat flour.” But in today’s high efficiency flour mills, the tens of thousands of trillions of wheat kernels made into flour each year are broken and separated into individual components – bran, germ, outer endosperm, finer internal endosperm – and then recombined to produce typical packaged whole wheat flours.

I hate to sully the romance of whole wheat, stone ground flour. People who lived on diets heavy in stone ground flours also ate so much stone dust as to grind their own teeth down to the quick. So much for romance.

Having broken the grain into components (called “streams” in the mill), let’s think about them. It would help to examine a drawing of the anatomy of a wheat kernel, which can be quickly discovered on-line (just search “wheat kernel”). A breadmaker’s perspective, the kernel includes three basic components – Bran , Germ, and Endosperm. Here’s a very simple image from Canada’s Old Stone Mill. :

Bran. This is the brown or tan outer coating of a grain. When removed, two to three distinct tissues are included: • Pericarp. This is hard, tan, dry fruit wall. It is not rich in starches, but good as ruffage. Bran is coarse, and gets in the way of delicate textures. So it is not a favored ingredient when the objective is to make a beautiful loaf. • Testa. Melded solidly to other layers, just inside the fruit wall is the residual seed coat, the testa. •Aleurone. See below….

Germ. In removing bran, the germ is also knocked apart from the endosperm. This is the embryo, consisting of primordial shoot and root tissue. The germ is rich in oils, and when exposed to oxygen it spoils quickly.

Starchy Endosperm. The interior endosperm mills into the whitest flour, because it is incredibly starch-rich. But endosperm also has yellow carotenoids, which lend a creamy yellow color to fresh flour. Historically, cooks and clients have considered that color undesirable, so many white flours are bleached (using any of several chemical and temperature treatments) to eliminate the color. Alternatively, aged flour (properly stored away from bugs) whitens over time as the carotenoids break down. •Aleurone Layers. The outer endosperm layers (just beneath the seed coat) make the most nutritious flour for humans diets, because they are richer in proteins and oils than the starchy inner endosperm. They are mostly milled away as part of the bran. Aleurone cells are active in producing enzymes necessary to mobilize endosperm starch during germination. White flour is made from the starchy endosperm, and is therefore not as nutritious as whole wheat flours. To restore nutritional value, white flours are enriched with niacin, iron, thiamin, riboflavin, and folic acid. [From Wikipedia: “According to the FDA, a pound of enriched flour must have the following quantities of nutrients to qualify: 2.9 milligrams of thiamin, 1.8 milligrams of riboflavin, 24 milligrams of niacin, 0.7 milligrams of folic acid, and 20 milligrams of iron.”] For our recipe, I specified “bread flour” – which reminds us that all of the proteins in flour are not in the aleurone layer. There are truly important proteins in the starchy endosperm, and they vary in concentration based on the kind of wheat being grown. Soft wheats, which yield flours used for “tender” breads, like cakes, have low protein content (about 8-10%). Hard wheats, which yield flours used for chewy breads and pastas, have 10-14% protein content. That protein is the notorious “gluten”. Crucial to making beautiful yeast-risen breads, gluten creates the elastic infrastructure that sets to create structure when the bread is baked. The starches that make up most of the endosperm gelatinize to create the bulk and softness that surrounds the protein infrastructure. The gluten protein is not as water soluble as starches and sugars in flour, so manufacturers are able to wet and knead flour, then wash out starches and isolate pure gluten – which you can purchase. Almost any store with a strong offering of health foods will sell gluten, in bulk or in boxes.

A Sticky Experience: Pour some gluten in a bowl and mix it with water. You quickly have a snotty and sticky mess. Students are astonished at this. A mass of wet gluten bounces like a superball. And it gets everywhere. It is worth the mess. Handling gluten is an important part of the story. In reality, gluten is not a single protein., rather a mix in which the specific proteins glutenin and gliadin predominate. They may be present in other grains, but only in wheat are these proteins both present and balanced to give dough the right consistency for the “well risen loaf.” Finally, check out the germ (bottled). Open the bottle and give it a taste. This stuff is delicious, buttery and rich. No wonder it goes rancid so quickly. Once the jar is opened, the germ will spoil soon, even under refrigeration – so use it up. It’s a great embellishment on top of a bowl of cream of wheat. When you eat germ, you are eating the embryo. If you have wheat grass (through germinating your own wheat kernels, or having purchased a square of wheat grass that is sold for juicing), take a few moments to compare the kernel to the seedling. Note the shell of the grain is probably still attached to the seedling, but it is soft and hollow. The entire endosperm has been spent, or rather mobilized and utilized. It was the energy in the endosperm starches that nourished the emerging wheat seedling. So how did a rock hard grain become this soft green plant in just a few days? It takes 1-2 weeks to grow wheat grass, and people often start wheat grass by soaking the grains. As the grain takes in water, the germ generates hormones that stimulate cells in the aleurone layer to produce enzymes needed to break starches into sugars. Those newly available sugars provide the energy and building blocks required for growth. People take advantage of this stage in germination in order to create malt, which is rich in those useful enzymes – something that can used break down starch for many purposes. We call this malt-generating process “malting”. That means people soak cereals (often barley) and keep them moist until germination starts. The germinating kernels are gently heat dried (not cooked), and ground, then used as an additive that promotes starch breakdown for many processes, most particularly in the manufacturing of beer. As you can see, there is a lot to talk about here, and there is every chance you may have already given thirty minutes to these deliberations. Just in case, check your rising dough. I like to keep students absorbed in thinking about grains, talking about flours, inspecting wheat grass, and making a mess with gluten, so they completely forget the dough is busy.

Back to Breadmaking….

But if 30-40 minutes have passed, it is time to check. When we take that break and lift the towel, there is an audible gasp. With the instant yeast, this short time is usually sufficient for a doubling in size – which means it is time to deflate the dough.

I did not say punch down, because I encourage students to deflate the dough gently, using a modest kneading action. Then we let it relax for just a few minutes while preparing the loaf pans. That is pretty straightforward – just a coating of baker’s spray is sufficient. And don’t forget to turn on the oven (180 ºC or about 350 ºF) We then shape the loaves in a very simple way. Flatten the dough to a rectangle (at least 6 by 8 inches). Then beginning at the edge nearest you, and using your palms and fingertips, begin rolling the dough very tightly. It will make a tense cylinder that gains length as you roll.

Once rolled up, tuck the two ends into the loaf, and set it in the pan with the final seam on the bottom. If there are several people in the group (we have pans and oven capacity for 30 loaves), I ask students to write their names on the popsicle sticks and slide them upright in the pan alongside the loaf – so each person can reclaim his or her own loaf from the oven. You can elect to oil the top crust or not. Sometimes I will lightly spray this top crust with clean water, but that is un-necessary also. Cover with the cloth and set aside. 

A Bit about Rising: While the loaf is rising, make certain the oven is turned on and take a few minutes to talk about yeast and sugar. Remember yeast is alive. The powdered form has been protected from heat and desiccation, so once it is moistened and given a bit of food (in the form of sugar), yeast springs to life, reproducing vegetatively – and actively. Even when oxygen is available, if sugars are plentiful yeast prefers to break them down through fermentation (We normally think of fermentation as anaerobic, a breakdown process that only occurs in the absence of oxygen. But yeast is different. For a more technical discussion of this, look up the Crabtree Effect.)

The products of yeast fermentation are carbon dioxide and alcohol. I usually take a moment earlier in the session to dissolve a bit of sugar and yeast in a bowl of water, which by the time we get to this discussion has become a frothy, somewhat tasty concoction. Participants are amused at the foaminess, and most find the taste rich, reminiscent of the smell of rising bread and the flavor of some beers. That reaction is not universal – some people find the taste unpleasant.

This foam is good segue to consider the rising process. Yeast, living off the tablespoon of sugar (plus additional sugars made available through the breakdown of starches in the flour) we incorporated in the recipe, has generated carbon dioxide that inflated the loaf – filling and stretching bubbles made possible by the gluten we moistened and aligned through kneading (you don’t really have to knead bread if it is fairly wet and left to its own devices for a while). If this were sourdough, and we had used a starter, the work would not have been by yeast alone. Sourdough hosts an entire community of yeasts and bacteria that will do this job for you, and they will generate additional flavor compounds along the way.

Sugar has its own stories, as there are few plant products that have impacted human health and happiness so profoundly. Core to human genetic makeup is a predilection for sweetness in foods. We are told there are only four or five tastes that function apart from smell, and sweetness is one. Many of us learned that sweetness is detected by the tip of the tongue, but the concept of the “tongue map” is now regarded as a myth. What we perceive is a chemical property of many related compounds – most of which would be classified as sugars. In table sugar, sucrose, sweetness comes from the two sugar components (glucose and fructose), with fructose being perceived as the sweeter of the two. (The word fructose relates the common term “fruit sugar” – because fructose is the typical sweet agent in ripe fruit.)

Regardless, sweetness is nearly universally pleasurable. The granular sugar we added to the dough may have come from sugarcane, which is a tropical grass, native to the Indian subcontinent. Before trade, imperialism, and globalism altered availability, most societies had paltry access to such processed and concentrated sweeteners, and relied on plant fruit and syrups. Native Americans had discovered the sap of Sugar Maple. Europeans doted on honey, and dried grapes to make sweet raisins. Dates were a staple in North Africa. Asian cultures domesticated peaches and apricots, persimmons, and sweet oranges, which formed the basis of their desserts and liquors. These are all sources of fructose and glucose, and you can make bread using any source, whether sucrose (each molecule of which is one glucose attached to one fructose) or fructose or glucose – the energy does not have to come from processed white sugar.

But the bulk of sugars in flour are tied up in starches required for structure, and still some kind of sugar has to be included to power this living reaction. Moreover, added sugar may be needed to support a second (or in the case with some breads, even a third) rise. Some of that additional sugar will come from the flour itself – recalling that slow breakdown of starches in the flour yields sucrose, but the recipe and conditions determine balance. When there’s the right amount of sugar and the alchemy works, the loaf we formed of a dough that has undergone one rise, will double again – in about 30 minutes, and it’ll be time to put the loaf in the oven.

That yields a few moments for some useful to talk with students about cane sugar. Living in a warm temperate climate, such as Florida or Southern California, I can often find a clump or stem (culm) to show to students. That’s instructive since many people have never encountered cane, even though sugar and sugarcane have been major issues in world politics for centuries.

It’s sobering to recount the story of sugar, its wonderful but often tragic consequences. This grass, native to New Guinea, became one of the world’s most precious and desired commodities. We know the ditty that reminds us Columbus sailed the ocean blue in 1492, but he made that voyage again and again – four times. By his second voyage, Columbus had established plantings of Sugarcane in the Caribbean, plantings that yielded their first commercial crop in 1505. [search the Reader TimeLine for sugar] This was significant – Europe was determined to have access to sugar. But the growing of cane and production of crystalline sugar is work-intensive. Labor was required, and native peoples of the Columbus’s “new world” would come to suffer their own tragedies due to disease and exploitation. Fate would not turn the native populations to wholesale sugar production. That would fall to another, old world land – Africa. Within a couple of centuries, millions of slaves were taken from their homes in Africa to this Newe Founde World to support the always-failing business of sugar production. The entire slave triangle that enriched New England was founded on sugar plantations in tropical America. Examining the stem of Sugarcane, students begin to appreciate the backbreaking labor and complexities that needed resolution for sugar production. Juice had to be squeezed from the cane, collected, then boiled down to molasses that precipitates brown crystals. All of this required equipment, fuel to fire kettles, beasts of burden for hauling and milling, and human labor in the form of slaves. Regardless how meager the provision, workers required both housing and food. Managing those complexities and exploiting those resources drove great tranches of world history for over four centuries. Sugar tells other stories also, giving us the ultimate food for thought. Like cotton, we are tempted to blame sugar for many of humanities ills, but paraphrasing support for the second amendment – sugar doesn’t harm society, people do……

Unfortunately, there is too little time in the course of events to investigate that topic satisfactorily. Bread bakes in 25-30 minutes. Students reach some threshold when two hours have passed and the aroma of fresh bread wafts from the oven. We clean up, and usually sample the loaf I made as demonstration, sending the rest home with the students in the paper bags.

I remind students that cutting into a loaf of bread, fresh and hot from the oven, is both delightful and sacrificial. Though cooked, the internal structure does not set until bread cools a bit. If you cannot resist, and just have to take the end piece of a loaf right from the oven, use a good bread knife and take care. By the time the internal temperature hit 90 ºC (about 195 ºF), the proteins were cooked and the starch gelatinized, but both remain soft. Externally, the loaf is close to oven temperature; the crust is brown and resilient to a knife. This makes circumstances even touchier because a serious stroke of carving is needed to cut through the crust, while the interior is more like a wet soufflé. It is, therefore, easy to collapse the structure of the entire loaf. Minimally, you will discover this when spreading butter on a hot slice – the crumb collapses to a wad.

I’ve worked through breadmaking with many groups, of every age, always with two goals. Of course I want people to appreciate how the nature of plants impacts our lives in such fundamental ways as giving us our daily bread. But a second goal relates to personal competence and confidence. To me, it’s important that participants personally make and bake their bread. It is such a simple yet profoundly satisfying and useful skill, something you only need to conquer once. Knowing that you can make your own bread means you never have to say you’re sorry. 

Activity – Pizza dough

Generally, pizza making involves using dough prepared a day or two earlier, which means your schedule may not allow for making dough, or for a full discussion of grains, yeast, and sugar. But if you have the time, there is a lot to be considered. It is very logical to plan an extended activity (multi-session) that includes people making the pizza dough. And, you don’t have to go for a slow rise; excellent pizza can be made with freshly-risen dough.

Pizza dough is seldom enriched with milk or egg…, it’s basically flour, yeast, oil, and water – the flour being determinative. Pizza crust can be made with almost any flour, and many recipes for pizza crusts include whole wheat flour. Indeed you can purchase crust made from ground-up cauliflower to avoid wheat proteins (i.e. glutens).

But the basic recipes often call for white flour, most traditionally Italian “00 caputo” flour, a finely milled, hard flour with about 10% protein content. Instructions for pizza dough often call for Neapolitan-style flour, which is a finely-milled (’00’ is a designation for this fine texture) medium-hard white flour. What does that tell us? First, it’s a white flour, which means it includes only streams after the bran and germ were chipped off. Secondly, it is very finely textured, which limits it to the finer (ultimate) streams coming from the rolling mills. More intrinsically, it is milled from wheat with a native content (or a blended content) of about 10% protein. You can determine the protein content by reading the ingredients label, which informs us that a portion of about 100 grams (1/3 cup) includes 10 grams of protein. Many recipes add Semolina, made from a harder wheat, which will increase the protein content of the dough, giving it a chewier texture.

The recipe included below incorporates two kinds of white flour, ’00” and Semolina, a gritty flour made harder Durum wheat, with protein content up to 14%.

Other Acts of Fermentation: Breadmaking is just one of several complex inventions that showcases relationships between science, art, culture, and history . Today, with the expanded access to information through the internet, you can explore similar relationships with many related processes. If this is of interest, check out some of the following: • Making of Sauerkraut and Kimchi • Manufacture of Soy sauces, Tofu, and many complex soybean-based products • Manufacture of Worcestershire sauces • Spirits – the making of beer, wine, and hard alcohols 

Link to this Page: https://botanyincontext.com/botany-of-breadmaking/