Help, I’m out of yeast!

Anyone who knows me know that I bake––in case the posts about ancient bread and slew of baked goods on Instagram didn’t give me a way. The recent pandemic has inspired many people, and quite possibly everyone, to start baking, creating a shock to the flour supply chain and sold many stores entirely out of yeast. I have primarily baked using a sourdough starter for a few years now, but since I have had several conversations with people in the past two days, I thought I would collect that advice here.

Commercially-available yeast, at least in the United States, is most common either as active-dry or instant yeast (active dry technically needs proofing to activate the yeast, instant has more living cultures straight from the packet), in a shelf-stable dry version developed by Fleischmann’s during World War Two. Both types are baker’s yeast (Saccharomyces cerevisiae) harvested from a strain first isolated in the 19th century by Louis Pasteur and protected from other yeasts and bacteria like lactobacillus that occur naturally in the environment in order to produce a regular, reliable product.

The creation of commercial yeast makes baking easy, but people have been baking without it for thousands of years, so there are plenty of options for anyone who wants to keep baking. Here are four tried and true replacements for commercial yeast:

1. Make unleavened flatbreads. Passover might have just passed, but you can make matzah anytime, and the best soft varieties are just an an unleavened flatbread. Similarly, you could go with Indian Roti or flour tortillas pretty easily.

2. Make soda bread. Yesterday I declared beer bread a waste of good beer, but every once in a while it goes very well with some honey or maple butter, and there is a whole world of soda breads that you can try. These breads using baking powder and/or baking soda (sodium bicarbonate) as its leavening agent. Too much of the leavening agent can leave an unpleasant taste in the mouth and most simply aren’t to my taste, but they are an easy workaround if you don’t have yeast. Try this one for a cheddar cheese enriched soda bread from King Arthur Flour.

3. Harvest yeast from raisins. Seriously. A few years back I came across a story about a baker in France recreating the bread distributed to French soldiers during World War One. His scratch yeast came from raisins, which makes sense given both ancient precedent (Pliny the Elder mentions creating levain from millet kneaded with grape must, NH 18.26) and that the original baker’s yeast was identified on the skin of grapes. This technique is easily recreated at home; I promise that your bread will not taste like raisins unless you actually add raisins to the dough, at which point you are on your own.

4. Just make a sourdough starter. As Instagram culture and social media in general fuels all manner of anxieties surrounding people’s body and lifestyles, so too does it drive attitudes around sourdough. There are hundreds of videos about making the rustic Tartine country loaf. I know, I’ve watched them, and I still regularly fail to create the perfect loaf. My oven sucks, I don’t have the ideal dutch oven, I am notoriously ambivalent to precisely-weighing my ingredients* and yet my sourdough starters (I actually have two) still make spectacular breads without a hint of commercial yeast. My easy go-to bread is a simple sandwich loaf enriched with just a little bit of sugar and milk.

*This only holds true for breads; cookies and cakes require much more precision.

In short, the idea that you have to be “ready” for a sourdough starter is a myth, and with a little bit of care to adjust for different ratio of flour to water you can make any recipe. I’ve been known to tag Instagram posts with #sourdougheverything.

(To do this, prime the starter with water and flour to get it going ahead of time, and then add this to the recipe, adding extra flour a little at a time to reach the right dough consistency. The amount of flour will vary based on a number of factors, including how wet your starter is, how much of it you use, and the type of flour you’re using. You will need to allow more time, up to 1.5 or 2x, depending on the temperature and the starter’s activity, over what the recipe calls for with commercial yeast.)

Much as with harvesting yeast from the skin of grapes, natural leavening has been around for millenia, cultivating strains of yeast from the environment and the flour itself. The process is actually very easy––all you need is time. There are numerous guides available online and if you’re worried about harmful bacteria, use one with citrus which inhibits the growth of those strains until the good stuff can take over (grapefruit juice is the most common; I used lime).

Once the starter gets going, it is actually quite easy to maintain. I have been using two sets of the same strain cultivated in my kitchen for year, sometimes going as long as a few weeks between feedings. I keep my starters in Tupperware in the fridge taking out a small portion and building it up in preparation for each bake. When the base gets low, usually about once a week at my rate, I refresh it using a 1 cup of water and roughly 1.5 cups of flour and letting it feed for a few hours until it becomes fluffy and doubles or so in volume before it goes back into the fridge. Here are more detailed instructions.

I might be a sourdough heretic in some respects, and my instructions do not bring the starter quite to its most active the way that the instructions that call for three or four feedings in the day or so right before baking, but it is an easy way to manage a starter without discarding any of it.

Happy baking!