April 4, 2013
I’ve received a few questions about yeast lately, and as I began to type a response to one in Facebook, I decided that it would be just as easy to put the answer into a quick post, so that all of you could benefit.
Here’s the first question:
I have a question about yeast. Is yeast all the same, whether it’s ‘bread machine yeast’ or otherwise? Also, how is it possible to have yeast in gluten-free breads?
Yeast is a single-celled, microscopic fungus that converts sugar into alcohol or carbon dioxide. (Sidebar: we also have a post on Gluten Free Alcohol.) It’s basically a little living factory that produces the carbon dioxide gas that makes bread rise. There are many different strains of yeast fungi “in the wild”, i.e., in the air around you. Manufacturers grow huge vats of particular yeasts and process then in a way that they can exist in jars and little packets until we are ready to use them. Here’s more reading on how yeast is manufactured, if you’re interested.
In the U.S. you’ll typically find two kinds of yeast in the grocery store: bread machine yeast (also called instant yeast) and active-dry yeast. Instant yeast is processed differently than active-dry yeast and can shorten the rising time of the dough by up to 50%, according to one manufacturer. This is useful in gluten free breads, because the nature of a Gluten Free Flour Recipe, it might be required that our breads rise more quickly. Instant Yeasts and/or Bread Machine Yeast is what you will find in my refrigerator even though I never use a bread machine anymore.
The only time that I use active-dry yeast is when I’m going to be freezing a dough or putting a dough into the refrigerator to rise overnight. Instant yeast is not recommended in refrigerated or frozen doughs, so when I’m planning to make a batch of gluten free doughnuts or yeast rolls, I pick up a few envelopes of active-dry yeast.
In order to be gluten free, we only have to avoid the gluten that is in wheat, barley and rye grains. Since yeast is a uni-cellular fungi, it does not contain gluten. There may be other health-related reasons to avoid yeast, or to use wild-yeasts to make fermented “sourdough” bread, rather than using manufactured yeast. However, if you are looking at the narrow question of whether yeast is gluten free, then it is.
It is possible to make gluten-free sandwich bread without yeast, but you have to know a few tricks to get the bread to rise well. The explanation for why tricks are required and a video demonstration of said tricks are included in my Cooking Classes.