This month on Kitchen Geekery, Dr. J. explains the mysteries of gluten - and what it does to our baking!
Suppose Jimmy Kimmel’s camera crew stopped you on the street and asked you to explain what gluten is. Would you honestly be able to answer the question? Jimmy Kimmel quizzed people about gluten to prove a very controversial point about people who have made a gluten-free lifestyle choice, but I’d rather avoid that topic of discussion altogether, thank you very much.
In general, most of us food bloggers refer to gluten at some point in our recipes (with bread recipes, we encourage people to knead the dough to form more gluten, while with cakes and pie crusts, we tell people to not overmix/overwork the doughs and batters to avoid making too much gluten).
So I have to ask you the question: do you know what gluten is?
What is gluten?
The most common misconception is that wheat-based flours, like that good old all-purpose flour we use for baking, have gluten.
In fact, all-purpose flour doesn’t have gluten as such, but what it does have is two gluten proteins (glutenin and gliadin) which form a network when they come in contact with water and a little elbow grease (in the form of mixing or kneading). When you mix all-purpose flour with water and knead them together, glutenin and gliadin come together to form a network that we call gluten.
That gluten starts out pretty messy (think of bread dough when you first mix ingredients together), but the more you work it, the more the proteins rearrange until they form a more structured, pliable, elastic network (think of how smooth and stretchy the bread dough is when you’ve kneaded it for several minutes).
There’s a reason kneading is such hard work and so important: the structure of gluten gives physical strength and elasticity to your doughs. With proper amounts of water and kneading, you can work your dough into a lovely mass that stretches instead of tearing when you pull on it. That’s all thanks to gluten.
When is gluten a good thing and when is it a bad thing?
In bread making, gluten is essential. The network of proteins in gluten allow gas bubbles to form, expand and hold their shape in bread doughs, instead of escaping. Breads with a chewier texture, like delicious Montreal bagels, require more gluten. Breads that rise up tall also depend on a high gluten content to allow for expansion of the dough without breaking or collapsing.
On the other hand, for pie doughs and cake batters, most of the time, you want to avoid overworking the mixture to prevent too much gluten from forming. Of course, there’s a catch here: too little gluten is also a bad thing in the case of pie dough, for example.
I went through a phase where I thought I was a pie-making rockstar because I didn’t use any water to make pie dough. Eventually I realized my pie crusts were delightfully flaky, but with nothing holding them together. If you add no water to a pie dough recipe, sure enough, pie can still be made, but the crust is extremely delicate and crumbly, hard to work with and difficult to serve: there wasn’t enough water to form gluten in the dough, which means there isn’t enough gluten to hold the crust together. So, there’s a reason why you need to add water to pie dough: a little water allows just enough gluten to form, which helps hold the dough (and later, the baked crust) together.
Some factors affecting gluten development and strength:
- Water can help but also hinder the formation of gluten in doughs:
- too little: gluten can’t form because water is essential for forming the gluten network. Dough will be crumbly.
- too much: excessive amounts of water interfere with the interactions of the gluten network, which falls apart. Dough will lose structure and turn to mush.
- Salt enhances gluten formation by favouring the interactions between the proteins of gluten
- Sugar, like flour, interacts with water, therefore the more sugar in your dough, the less water is available to form the gluten network, thus decreasing the formation of gluten
- Fats tend to bind the proteins of gluten, preventing them from interacting with each other to form the gluten network.
- Acids (like vinegar) also interfere with the gluten network so a little vinegar added to your pie crusts means less gluten will form.
- Flours with a lower protein content (like pastry flour) means less gluten proteins and therefore less gluten formation when you are making cakes and pastries.
I hope that after reading this, if Jimmy Kimmel were to stop you at a street corner to quiz you about gluten, you would be able to at least say that gluten is made up of proteins that form a network when flours (such as wheat-based all-purpose flour) are worked together with water!
Kitchen Geekery is written by Janice Lawandi. Janice is a PhD-chemist-turned-baker, which is why she loves to use science to understand and solve problems in the kitchen. She is currently working as a recipe tester and writer in Montreal, QC. Visit Janice’s blog, Kitchen Heals Soul, for more baking science and inspiration. You can also follow her on Facebook, Twitter, and Google+.