A Tale of Two Yeasts

There Is No Yeast Shortage

Back story: Thanks to the epidemic “lock down” I’ve had time to take up old hobbies, like creating my own sourdough starter. So last month I reviewed the many YouTube videos on the subject.

One of the most common statements I encountered was that yeast spores exist in the flour used to bake breads and other baked goods. So “collecting wild yeasts” is simple: just mix flour & water in a 50–50 ratio by weight.
I did that and began the recommended 10 to 14 day daily feeding regimen.

But at the time I didn’t pay any attention to the related claim, that wild yeasts also exist on fruits we buy at the grocery store. So it wasn’t until yesterday I decided to try using one suggested source: raisins. The instructions are only that you first soak a small quantity of the “source” fruit (raisins you know are dried grapes) in a small quantity of water (preferably non chlorinated). I used a 1-ounce box of name brand “California sun-dried raisins” I found in the back of my cupboard. (possibly more than a year old).

I put the raisins in a small cup and added about double the volume of spring water. Let it stand and then stirred until the water became cloudy. Strained out the raisins and then just used the cloudy

Why was I interested, you might ask. Because I had observed that the yeast I had collected from unbleached flour was not doubling in size between feedings. (“food” is just a 50–50 flour & water mix by weight — using a digital kitchen scale). It was bubbling up but never reaching the double-size mark. This is significant because you need the yeast to be that robust and active in order to make your bread dough rise enough to get the right density in your baked loaf.

But in addition: sourdough gets its tangy flavor not from the wild yeast but from a particular kind of bacteria-lactic acid bacteria. Without that bacteria, you still get “standard flavor” from the active yeast. And to get the right bacteria you have to be lucky or just keep feeding the yeast until the bacteria get through the paper napkin filter you’ve secured over the mouth of the jar you have the yeast in. You will know when that’s happened when the odor becomes “funky” and not just “yeasty.” Then the yeast and bacteria go through a balancing process until the odor becomes “yeasty-tangy.” This is the reason you need to keep feeding the starter for several days (10 to 14 is the most-often mentioned period).

It was when I got the fast result of a more robust yeast that I also began to think that the yeast from California was also a better prospect than the yeast floating around in my apartment. I’ll leave that for readers to decide.

I should have begun by using raisins or other (not citrus) fruits, fresh grapes, peaches or plums would have done as well and I would have saved myself a lot of time. That is why I’m passing on this information now — to save others that amount of time and I’m trying to provide some useful details so that others can find their own source of baking yeast without being dependent on the grocery store supply line which is currently pretty unreliable.

But clearly: there is no yeast shortage.