Yeast is hard to find, but you can make your own at home.

First came the quarantine. Then came the baking boom. Now, we’re staring down the barrel of a serious yeast shortage.

That’s right, folks: with everyone trapped at home and attempting to operate a makeshift boulangerie out of their apartment, the yeast supply chain has been thrown into total disarray by a completely unexpected surge in demand.

“I’ve been with the company for five years, and this is by far the highest demand I’ve ever seen,” John Heilman, vice president of Fleischmann’s Yeast producer AB Mauri told Slate. Specifically, Mauri notes that the March increase was somewhere in the neighborhood of 600 percent compared to the prior year. Normally, demand for yeast and other bread products usually peaks around the holiday baking season in December.

Part of the holdup has to do with the fact that time is one of the key ingredients in baking yeast, even on an industrial scale. While major players can organize massive quantities of the single-celled fungi and feed them the sugar they need to become a good baking yeast, large-scale fermentation will always require a certain amount of time, usually measured in days if not weeks.

“Yeast takes a certain time to go from one cell to two cells, Sudeep Agarwala, a Gingko Bioworks yeast geneticist, told Slate. “You can do everything you can to speed it up, but there’s a hard limit to how fast they can double.”

Beyond an inability to transcend the basic principles of biochemistry, baking yeast has also run into some of the same challenges that’s kept certain commodities off of store shelves during the pandemic: packaging problems. Heilman told slate that the facilities it relies on for packaging materials are either closed or running low on materials. While there’s no reports on whether or not something like this would happen for yeast, the FDA did recently ease packaging restrictions on eggs in the hopes of getting more of them to market faster.

The good news in all of this is that you don’t need to own a factory to produce yeast. In fact, it just takes some old flour, water, and a bit of dried fruit—plus time. After storing that mixture somewhere warm for about 24 to 48 hours, you’re well on your way to having the starter you need to bake. While it may not necessarily yield what you think of as sourdough, the resulting bread will be uniquely yours, as this handy Twitter thread explains.

So in short, there’s no need to panic about the absence of yeast from shelves. Unless you’re baking to de-stress between hospital shifts, most of us probably have the time and the patience right now to make bread forged from our own raw materials. At the very least, it’s a heck of a lot cheaper and easier than trying to make your own eggs.