As a Vermonter, I know all about cold. As if roughly 6 months of winter weren’t enough, we also have a long mud season each spring. In the fall, we get lots of visitors to enjoy the foliage, but locals know that those changing leaves mean frosts as early as September some years.
How does all this cold weather affect ferments bubbling away on the countertop?
Cold Weather and Quick Ferments
Some things ferment rather quickly, in a matter of hours or just a few days. Good examples are sourdough bread and fermented fruits or jams.
For fast ferments, cold weather is easy to overcome. Just make sure those ferments are kept near a heater or wood stove so that the bacteria can properly multiply and do all their good work.
In my house, that means taking rising dough down into the basement and placing it right by the woodstove. A good spot is about 5 feet from the woodstove when it’s going hot, and about 2 feet from the stove when it’s letting off slow heat.
Gauging the right distance can be tricky, but use your own bare skin as a guide. The air should feel just slightly warm to your skin, and you shouldn’t have any temptation to pull away. Cozy for you, is cozy for those probiotics that are going to be living and working in your gut long after you eat your ferments.
Cold Weather and Slow Ferments
What about ferments on a longer timetable? You don’t exactly want sauerkraut to spend weeks and weeks near a wood stove. Vegetable lacto-ferments actually benefit from a long slow fermentation process, and keeping them in cold climates and colder parts of the house can mean that they’ll preserve your fall vegetables long into the winter months.
Keep in mind that lacto-fermentation was originally a way to preserve food during the winter months in the absence of refrigeration. How would pioneer and settler families have made sauerkraut?
Obviously, they would have been doing it in the fall or winter months when fresh cabbage was available, and then that ferment would have kept slowly bubbling through the winter months and into the spring.
Longer, slower, cooler fermentation actually allows more flavors to develop in your home ferments, while at the same time helps the foods stay fresh longer. In our fast-paced society, we expect to be able to have homemade or home fermented foods fast.
The most complex and nuanced fermented flavors happen when vegetables are fermented at around 50 degrees F, but that means that vegetables can take as much as 6 months to reach maturity. Warming the temperature up to 60 to 70 degrees means that you can have foods in 6-12 weeks, which fits better with most people’s patience.
Historically, a large crock of sauerkraut was stored in the basement or root cellar to keep it fresh all winter long, and I’ve heard stories about how Korean families have fermentation crocks cemented into the concrete foundations of their homes to help keep them colder.
Cold Weather and Homebrew
Colder temperatures can be problematic for some types of home-brewed beer that depend on consistently warm temperatures. Other beers, like lagers, actually require cold temperatures to ferment correctly. If you’re in a cold climate, consider switching to cold-loving yeast strains during the cold months of the year.
Work with what you have. If you’re fermenting kraut, don’t bemoan the cold temperatures. Use it as an exercise in patience, knowing that your final product will taste even better than quickly made summer ferments.