Baking Science Questions

Flour Mixtures, Batters & Doughs

• Flour mixtures are main ingredient in bakery products, and depend on the liquid to flour ratio.
• Common foundational formulas/recipes contain flour, liquid (water, milk, etc), fat (butter, oil, egg yolk, shortening), eggs, leavening agents (yeast, baking powder, steam, etc), salt, and sugar

Batters

• Pour batters include pancake and shortened cake batters, thin or pourable, and a 1:1 liquid to flour ratio.
• Drop batters include muffins, quick breads, and certain cookies, use a 1:2 liquid to flour ratio, gluten development happens when mixing
• Sponge: a batter containing yeast

Doughs

• Doughs need to be thick enough to be handled or kneaded on a flat surface.
• They can either be stiff or soft.
• Yeast breads typically make stiff dough.
• Baking powder biscuits, rolled cookies, and pie crusts also make stiff dough.

Classes of Wheat

• Hard Red Winter is used in Asian noodles, hard rolls, and flat breads.
• Hard Red Spring is considered the aristocrat of wheat "designer wheat", and is used in rolls, croissants, bagels, and pizza crust.
• Soft Red Winter is a versatile weak gluten wheat which is excellent for milling and baking cookies, crackers, pretzels, and pastries.
• Soft White is a low moisture wheat with high extraction rates, and a whiter product in pastries and cake.
• Hard White is a new class of wheat, and is used in Asian noodles, whole wheat or high extraction applications pan breads, and flat breads
• Durum is the hardest of all wheats, it has a richer amber color, and high gluten content for pasta, couscous and Mediterranean naan breads

Milling of Wheat

• Basic steps include cleaning, tempering, breaking, separation and sifting, and grinding.
• Flour grades are determined by which streams are included in flour.
• The highest grade of flour is patent (extra short/fancy patent)
• The lowest grade of flour us clear grade flour, its mineral content is higher due to more bran (aleruone layer)

Maturing, Bleaching, Enrichment and Storage

• Maturing/aging and bleaching are 2 distinct processes.
• Maturing/aging and bleaching are necessary to produce quality yeast breads, maturing and bleaching agents may be used.
• Before maturing, gluten is weak, allows oxidation of glutenin and gliding allowing more bonds to form when gluten forms.
• Bleaching can occur naturally with time via oxidation of carotenoid pigments, this is considered unbleached flour.
• Bleaching can be done with chemical agents which speeds up process, these are labelled as bleached.
• Both types of bleaching have no nutritional differences.
• Maturing and bleaching agents may be added to freshly milled wheat, speeds up the process and lowers the cost to store.
• A variety of agents are used under Food and Drug Regulations- Food additives, examples; ascorbic acid and benzoyl peroxide.
• White flours can be enriched with B vitamins, and iron.
• White flour has a shelf life of 18 months and whole wheat flour can become rancid.
• They can be kept in the freezer for 2-6 months to prolong shelf life.

Bakery products

• All bakery products (regardless of leavening type) can have: flour, eggs, fat, sugar, salt and a leavening agent.
• Flours structure impacts texture, and flavor due to starch gelatinizing when moistened and heated to form a paste that stiffens
• Gluten forms an elastic dough when moistened and worked, more work leads to a stronger structure.
• 80% of flour proteins are gliadin and glutenin, these produce gluten when combined with water and manipulated.
• Wheat flour is preferred for bread baking because gluten, which provides structure, is responsible for viscous and elastic characteristics of dough, and enables high loaf volume.
• Gluten can be extracted by washing throughly kneaded dough with water to remove starch.
• This process creates seitan (wheat gluten), this is typically used as a meat substitute.
• Changing the type of flour will change the structure of the dough.
• Strong flours create light cellular products.
• Softer flours create more tender less chewy products.
• Gluten Formation requires water and manipulation.
• Manipulation: glutenin will form longer elastic structures while gliadin builds the viscous component of the dough
• Kneading = manipulation, increases gluten strength and realigns protein molecules, redistributes air bubbles.
• Factors affecting gluten development: type of flour used, temperature, sugar, fat, viscosity.

Leavening Agents

• Physical leavening agents include air, and steam.
• Chemical leavening agents include baking powder, and baking soda.
• Biological leavening agents include yeast, and bacteria.
• Air and steam incorporation happens during mixing, creaming of fat and sugar, sifting of dry ingredients, and whipping of egg whites. Steam: due to liquid in product like water, milk, and eggs.
• Chemical leavening is raised by carbon dioxide from baking powder, or baking soda reactions.
• CO2 is produced when an alkali reacts with an an acid in the presence of a liquid.
• To use Baking soda (sodium bicarbonate), an acid must be present
• Baking powder: already has acid added (cream of tartar) & corn starch to absorb moisture to inhibit reactions and to help standardize.
• Adding baking soda to a product/recipe without an acid will cause it to break down, it will discolor and result in a soapt taste.
• Baking soda with the addition of an acid with hydration will start the reaction, creating a production of CO2
• Using cream of tarter will cause the reaction to occur quicker, with the hydration it will start the reaction and produce CO2
• Ingredients are mixed and placed in an oven, then the starch gelatinizes, the gluten coagulates, and the egg proteins coagulate (gas is produced), gas is trapped expanding mass-producing volume and cellular structure
• If gas production goes too fast during mixing, the gas escapes from the batter, and the cake isn't effective
• If gas is produced too, slowly, then the the gluten, starch, and eggs set, and crust is formed, gas is releasedrupturing causing cracks.
• Too much gas production (too much baking powder) will cause the cells to will over expand weakening and collapse, leading to course grained structure.
• Fast acting baking powder (available to bakers): single acting
• Slow acting baking powder (consumers): double acting water and heat
• Single acting baking powder: Sodium bicarbonate is the CO2 source.
• Double acting baking powder: SAS-phosphate baking powder (Sodium aluminum sulfate) will reacts to release C02 at room temp when dry, moist ingredients are added, and when heat is applied.
• Contains two acid substances that reacts with soda to release CO2 gas at different times in baking process.
• Acid 1: mono calcium phosphate, reacts with soda at room temp as soon as liquid is added to dry ingredients, it causes batter to become lights and porous during mixing.
• Acid 2: sodium aluminum sulfate (SAS), needs heat and moisture to complete its reaction with soda, produces additional CO2 gas during baking.
• Yeast: is the common strain saccharomyces cerevisiae, forms are compressed active dry and quick rise, raised through carbon dioxide produced during fermentations, when rehydrated yeast begins fermenting
• Compressed yeast has a short shelf life and needs to be used within weeks when opened. It is also known as cake wet / fresh when becomes active quickly
• Active dry has a longer shelf life needs to be activated prior to use, sprinkle on warm water leave for 5-10 mins creating foam when ready to use
• Quick rise is an active dry and a special strain that makes CO2 very rapidly, cutting fermentation time in half, ready to use as soon as package opens
• For yeast leavened products, fermentation rate increases over time due to liberation of sugars from starch due to enzyme activity.
• Also caused by yeast cells are multiplying over holding time of bread
• The fermentation rate increases because as the yeast grows they reproduce as a result of more yeast in the system there is fermentation, along with release of amylase, releasing more sugars which encourages yet more growth, and production.
• Oven spring (increase in volume about 80% of yeast breads during the early part of baking resulting from the expansion of carbon dioxide and the increased production of carbon dioxide stimulated by oven heat
• Kills yeast and inactivates enzymes, formed bubbles enlarge due to expansion of carbon dioxide and air
• Coagulates proteins and sets the structure
• Starch Partially gelatinizes
• Sugar has to be ties up with water, acts as a tenderizer and adds sweetness, many functions.
• Increases volume by contributing food for yeast t, raising gelatinization temperature allowing more time for gluten strand development, retains moisture, and turns brown
• Fat tenderizes, interferes with gluten (adds sweetness), Improves volume by melting batter making batter more fluid, improves flavor and color, adds flakiness, delays staling. Liquid hydrates flour, gelatinizes starch, activates yeast, acts as a solvent for dry ingredients
• Eggs are structure builders (protein), egg whites form films and traps air when whipped
• Salt adds flavouring, strengthens gluten, controls yeast growth

Assorted questions about baking science. Topics include flour mixtures, doughs vs. batters, wheat classes, gas production in batters, and the function of baking powder and yeast.