Flour (Part I) - The final ingrediënt

So I’ve touched on butter, sugar, eggs and milk. We’ve almost got a full (Quarter) Pound Cake. We’re just missing one very important and essential ingredient: flour. Which baked good doesn’t use flour? Honestly. This stuff is important and you know it.

Components of flour
First if all, what IS flour? To understand the purpose of flour it’s crucial to know where it comes from. Flour is milled from grains such as wheat. The wheat grains are made up of several layers:
 - Endosperm. The center of the grain. It contains starch, protein, carbohydrates and small amount of oil.
- Brain (bran). The outer husk of the grain. Contains mostly fiber, but also adds texture and colour to flour.
 - Germ. The reproductive epicenter of the grain. It contains the most nutrients. Flours with germ are rich in vitamins, minerals and fiber. It also contains a small amount of fat.
All flours contain the endosperm. Quite frankly, most (white) flours only contain this part. The bran and germ are found in whole wheat flours.

Proteins in flour
Flours can contain something between 6-14,5% proteins, which are all packed in the endosperm. There are as many as 30 different types of protein in wheat. Gluten is one of those proteins. Specifically, gluten is two proteins: glutenin and gliadin. When you add water to these two, they are drawn to each other and connect. This new protein is gluten. During mixing and rising, existing gluten threads touch. Thus creating more links to form longer strands of gluten. This gives elasticity and strength to baked goods. The gluten produce a strong web that traps air produced by leaveners. They expand when the dough or batter rises and set during baking. Thus providing the crumb of our baked goods. So the structure of our baked goods all depends on the gluten. How much gluten you have in your batter depends on:
       1) the gluten content of the flour
       2) the amount of liquid and
       3) the amount of processing.
More gluten will give a higher rise and more chewy results. But if there is too much gluten, your baked good will become tough and dry. It might not rise at all. Less gluten results in a more tender crumb. However if there is too little gluten, your goods could collapse after baking or become mushy.

For example, cakes have a fluffy texture and soft crumb. They demand a flour with a lower protein content and less time processing. Cake recipes will sometimes include “Do not overmix!” or “Place in the oven directly after”. This keeps the gluten-formation as low as possible.
On the other hand, breads demand a flour with more proteins. A flour with more proteins absorbs more water and makes a strong and springy gluten. Breads also need 5 to 10 minutes kneading to form an elastic dough. The longer you knead, the longer the gluten strands become and the more water is absorbed. Recipes for bread will sometimes call for “knead until it comes together”. Gluten strands continue to form during rising and kneading. Too much kneading might break them instead, resulting in a dense, tough and dry bread.

Purpose of flour
Flour gives our baked goods structure. It’s the starch, gluten and gas from leaveners that create the crumbly and airy texture of our baked goods. Especially those proteins determine if something is chewy and rubbery (higher gluten content) or soft and crumbly (lower gluten content). Flour binds the ingredients together and supports the batter. It contributes to the body and structure after baking.

Not only the proteins, but also the starch adds to the structure of baked goods. It absorbs water (called gelatinizing) and gives volume and a stabilized structure. It breaks down the gluten, tenderizing it and giving it that light, delicate texture. During baking starch absorbs the water from the gluten. This helps the gluten set and become rigid. These gluten structures trap the gasses from leavening. As a result the baked goods don’t collapse after baking. Sugar and fat inhibit the starch gelitinization.

Flour adds a whole pack of nutrition – from fiber to proteins, minerals and vitamins. It gives colour to our baked goods and a whole bunch of flavour. Try making cookies with white and wholemeal or corn flour – you’ll know what I mean! Flour provides sugar and proteins for the Mailliard reaction, giving baked goods the brown-baked colour.

But there is more! Since starch can absorb water so well, flour can be used as a thickener. Pies, custards, sauces, creams and fillings make use of this aspect. Through dusting, flour can prevent a dough or batter from sticking to pans or other surfaces. It can also be used to coat fruits and nuts before going into a batter. This prevents them from sinking to the bottom of the pan when baked. Lastly, flour also adds to baked goods by providing food for yeast.

Storage of flour
In general, the longer flour is stored the more moisture it loses. Extreme temperatures and humidity may lower the quality of the flour. Since it’s so sensitive, the same flour may weigh different on a wet or dry day. It might also require more water to achieve the same product. For the best results, keep flour in dry, airtight containers in a cool and dark place.

Since this post was getting so-so long, I decided to divide it into 2 parts. I mean, Wauw! I knew flour was important, but that there’d be SO much to say?! So please look for Part 2! Where I explain all the different sorts of flours. A different type of flour can give such different results!

My References:
Bread by Christine Ingram and Jennie Shapter
Joy the Baker - What's the best salt for baking?
aboutfood - A Guide to Flour
JoyofBaking - Flour
culinate - The science of baking
CraftyBaking - Flour and Grains