The Chemistry of Baking
The following information is a place to converse about the Chemistry of Baking
Tentative Schedule
Chemistry Topics
- SOfIA students: put this in the order that you will be presenting, and put the correct name with the topic.
Flour Types
- Brandon
Basic Introduction
Flour plays a vital role in the chemical process of baking. Each kind of flour has its own special characteristics, which is why it's important to know which kind of flour will best suit your desired baked good. The biggest difference between the various kinds of flour lies in their protein content. This affects how the flours absorb water, for example: the same amount of water in a cake flour could lead to runny, more watery dough while it could lead to a more structured, firm dough with bread flour. Protein content also plays a large role in the development of gluten, which is responsible for the structure, rigidity, and texture of the intended product. I will later elaborate on exactly how reaction between flour and other ingredients leads to gluten production and such drastic differences in our baked goods.
The Different Kinds of Flour
- All-purpose flour: As its name suggests, this is easily the most versatile kind of flour on the market. Its average protein content varies by brand and ranges from 10-11.7%, so it produces enough gluten to give sandwich bread decent structure without being too wholesome. Bleached flour tends to be bland and flat in flavor.
- Cake Flour: This has a lower protein content than the all-purpose flour and averages 6-8% and therefore has much less gluten than all-purpose, which accounts for its finer, delicate crumbs. Most are put through a bleaching process, which changes the starches in the flour so that it can absorb more water and fat. (1 cup of cake flour is equal to 2 tablespoons of corn starch and 7/8 cups of all-purpose flour.)
- Bread flour: Bread flour has a relatively high protein content with averages from 12-14%. This results in a very high gluten development, giving artisanal/rustic breads their characteristic strong and chewy structure. This is often far too strong sandwich bread.
- Whole-wheat flour: This is made from all 3 parts of the wheat kernel (INSERT LINK)- the endosperm, the fiber-rich bran, and the vitamin-packed germ. These make it more nutritious, flavorful, and dense. Breads baked with whole-wheat flour tend to be heavy, hearty, and sour-tasting.
- Specialty Flours: There are a few specialty flours that the average chef will not encounter in their everyday lives and tend to be more useful to the professional bakers. These include:
- Pastry Flour: This flour is often used for pastries and contains a protein content between the all-purpose flour and the cake flour.
- Self-Rising Flour: This contains a leavener for convenience.
What's the big deal about flour?
Flour is a crucial component of the reactions that occur when baking. All flours naturally contain both alpha and beta amylases, which are enzymes that break the starch (link) in the dough down to fermentable sugars. These fermentable sugars are maltose and glucose. Scientists have looked at a way to bring the quality of slowly cultured starter dough to the doughs that many people use nowadays by enriching flours with more amylase enzymes. This expediates the process by breaking the starch down in less time, which means that there are more sugars available for yeast fermentation and a quicker production of carbon dioxide gas and ethanol, which gives dough its characteristic scent. As previously mentioned, protein content is responsible for each kind of flour's unique attributes. The two proteins that are important to gluten production are glutenin and gliadin. These proteins are hydrated when the flour is mixed with water, resulting in gluten formation. This is because these proteins are dominated by hydrophobic amino acids like glutamine, which has a strong tendency to form hydrogen bonds between protein strands. These hydrogen bonds are solely responsible for the structure and behavior of gluten. We see it as well-structure bread crumb from an artisanal loaf that you can get at a specialty bakery or the less-structured crumb of a cake or cupcake.
Water
Does water ion concentration have an effect of the baked good?
Sugar
- Rachel
Raising Agent/Yeast
- Sam (?)
Starch
- Tatyanna
Leaveners
- Gabby
Other Adjuncts
- Z, address this