There has been a lot of talk lately about being gluten free, and a lot of talk about how much better people feel after removing gluten from their diet. This leads to the question, what is gluten and what does it do? What purpose does it play in our food?
Gluten is a protein found in grains, with the highest amounts found in wheat. The gluten in a flour acts a glue and also creates a chewy product. Have you ever made flour wet just to have a sticky mess on your hands. That stickiness is from the gluten. The gluten acts as a balloon to trap air bubbles as they form. In fact, wheat flour is distinguished by the amount of gluten protein it contains. These different types of flours are used for different foods. Gluten in flour is measured as a percentage. Clearly, the higher the percentage of gluten, the more gluten is the flour.
Wheat is the most common type of flour. The most common type of wheat flour is All-purpose flour. This is a medium gluten content flour at 12%. As it has a medium gluten content, this is a good flour for most things. It works for breads, cakes, and cookies. Cooks who are really serious about their flour generally will use a flour that’s more attuned to the food they are making.
Bread flour has a high gluten content at about 14%. This is used for making crusty, chewy breads. More gluten equals more chewiness. This can also be called a “high protein flour”.
For lighter cakes and pastries, a cake flour should be used. Its gluten content is about 8%, far below the all purpose flour. Cake flours are good for making delicate foods, such as light fluffy cakes.
Finally, we have pastry flour. This flour has a bit more gluten in it than the more delicate cake flour and has a gluten content at about 9.5%. This type of flour is perfect for muffins and biscuits.
So high gluten content flours yield a chewy crusty bread. It is a heavier flour. Lower gluten flours will yield a lighter and fluffier more delicate pastry.
There are several other aspects besides flour that affects the gluten in your recipes.
1) Water. Without water, there is no gluten. Think about how light and fluffy flour is until you introduce water. Getting the right amount of chewiness requires the right amount of water. If you want a flaky food, such as a pie crust, add a little bit of water. If you add too much water to flour, you get too much gluten which will create a tough crust. There is a tipping point for your gluten. A fully hydrated dough will have the highest amount of gluten activity. Once the dough is fully hydrated, any liquid past that point will cause the gluten to weaken (think brownies and cakes).
2) Dough Handling. Handling a dough will organize the gluten proteins. The more you stretch, mix, kneed the dough, the stronger you are making the protein. That’s why you want to knead bread dough for a number a minutes, while you want to handle pie crust minimally.
3) Other ingredients. Fats will break the the gluten proteins down. Also, once the gluten granules are coated with fats, they can no longer absorb as much liquid. When they can’t absorb as much liquid, the gluten is not created.
Sugar binds up water, and inhibits the gluten formation
Salt makes gluten stickier and stronger.
These are the basics of gluten. What it is, what it does and how it changes based on other aspects of the environment. Whether you are gluten intolerant or not, it’s always interesting to understand the in’s and out’s of your food.