The COVID-19 pandemic has caused a shortage of many products in stores across the country. Whether because of supply chain issues, or hoarding and price-gouging, many items have been disappearing off of store shelves, like toilet paper, hand sanitizer, cleaning products, and canned food. One item that has been extremely hard to come by, which has surprised nearly everyone, is baker’s yeast. Above all, my favorite yeast is my potato sourdough starter.
It appears that while millions of people have been stuck at home with significantly more free time than ever before, many have turned to baking to cure boredom. This, in turn, has led to a large increase in demand for products like flour and yeast, and grocery stores have been struggling to keep up.
In light of this, sourdough bread has risen dramatically in popularity, since it can be baked without the use of commercial yeast. But what if you don’t particularly enjoy the taste of sourdough, or you don’t want to deal with the hassle of maintaining a starter?
Luckily, yeast is present in the air and all around us, and all you have to do is capture it and cultivate it in order to make your own homemade bread.
Yeast: A Brief History
You may be surprised to know that commercial yeast, aka, the granulated stuff you buy in packets at the grocery store, is only about one hundred years old. Humans, however, have been baking bread for thousands of years .
So what exactly is yeast? Yeasts are very, very tiny single-celled fungi- so tiny that it takes twenty billion yeast cells just to weigh one gram. The scientific name for the yeast we use in baking is Saccharomyces cerevisiae, which means “sugar-eating fungus”. This is what makes it capable of fermentation, which is the process that makes bread dough rise .
When yeast eat up sugars, they produce carbon dioxide and ethyl alcohol. In the case of bread, the carbon dioxide has nowhere to go because the dough is elastic, and capable of stretching. As the gas expands, the dough inflates and rises. This same process occurs in nature, when you see fermenting fruit. When a fruit becomes overripe and full of sugar, it breaks open. This exposes it to the yeast in the air, which lands on it and begins converting the sugars to carbon dioxide and alcohol .
Ancient Egypt is considered to be the home of modern bread, and Egyptian ruins have unveiled evidence of bread baking like flour-grinding stones and baking chambers, as well as drawings of bakeries and breweries that date back at least four thousand years .
It was not until 1859 that we began to understand what is actually happening when we bake bread, when Louis Pasteur first discovered how yeast works. Millions of yeasts can be produced from one cell, and once you have a large enough population of yeast, fermentation can begin .
How to Cultivate Your Own Potato Sourdough Starter
While this all sounds very scientific, cultivating your own yeast at home is not as complicated as it may seem- all you need is water and a potato. Ashley, who owns and operates the blog Practical Self Reliance, has recently shared her method for cultivating wild yeast.
The idea behind this method, which is the same one that was originally used by vodka distillers, is very simple and cultures yeast on boiled potatoes without encouraging the lactic acid bacteria that are responsible for sourdough .
Here are the basic steps for making a potato sourdough starter:
- Boil a single potato for 35 to 40 minutes, or until it is completely soft.
- Pour the cooking water into a separate container to allow it to cool, and mash the potato.
- Place the mashed potato into a one-quart mason jar, and cover it with the cooking water that you set aside previously. The jar should be completely filled with water. If you’re short on water, you can add chlorine-free drinking water to top it off.
- Set the jar on the counter without a lid (you can cover it with a towel if you want), and wait about 24 to 36 hours. At this time, you should see the first tiny bubbles beginning to form.
- Put the lid on the jar and shake it vigorously to distribute the yeast, then open it up and leave it on the counter again, uncovered.
- After another 24 to 36 hours, there should be plenty of bubbles. You now have an active yeast culture, and can begin baking bread .
You can speed up this process by adding other ingredients like sugar or a bit of flour, but they are not necessary to get an active culture going.
It is important to understand that bread made from wild yeast will take much longer to rise than bread made with commercial yeast, so you have to be willing to be more patient with this type of bread-making.
Your wild yeast culture can be stored in the fridge if you’re not ready to bake with it right away. It should last a few weeks in those conditions, and all you have to do is bring it up to room temperature when you’re ready to bake .
Things to Watch Out For
Ashley explained that, as with any new kitchen project, there’s plenty of opportunity for error and for things to not turn out the way you intended or hoped for, but you should know what the finished product should look, smell, and taste like.
“The finished yeast starter should smell pleasant, very lightly of yeast, like rising bread. Possibly ever so slightly sour like sourdough, but mostly like yeast.” 
If your starter smells really bad, that is a signal that something went wrong, and that you possibly cultured something other than yeast. If that is the case, you should get rid of it and start over.
Ashley offers the following tips to ensure your yeast culture is a success:
- Keep the container open to the air so the yeast have surface area to land on.
- Vigorously stir or shake the jar. This will distribute the yeast properly and oxygenate the water to prevent anaerobic bacteria from growing.
- Peel the potato, because the potato will give off-flavours to your starter. You should also make sure it is thoroughly cooked to the center before mashing.
- Use unchlorinated water. Chlorine can prevent yeast from growing, but may not prevent other forms of bacteria from growing.
- Once your culture is ready (its bubbling vigorously), put it in the refrigerator to prevent mold or spoiling.
Check out her full blog post for step-by-step instructions for creating your own yeast culture. Alternatively, if you want to make bread without any leavening whatsoever, try this easy recipe for Navajo flatbread instead.
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