Fermenting in the Heat


Most home fermenters are aware that heat speeds up the fermentation process. For some this is preferred because it allows us to go through the fermentation process faster, which gives us our beloved fermented food even quicker.

But heat as its drawbacks, especially when it gets above 90 degrees. And if you live in the south, or another hot climate, and don’t have air conditioning, this may be a huge factor in how you ferment through a good portion of the year.

Since I’ve moved to the south I’ve had to learn a lot about fermenting in the heat. Our little off-grid cabin doesn’t stay below 90 degrees for much of the summer, so after some problems with mold and other unpleasant situations, I’ve changed a few of my fermentation practices.

Less Overall Summertime Fermentation

I’ve been known to have four or five different ferments going at a time. Many of these involve a mother culture, like kombucha, sourdough, and kefir; so you must keep them going to keep them alive. But it’s just a lot to handle when they’re fermenting at a rapid rate as they do in the heat.

I’ve been trying to drop any ferments I don’t have to keep going. So instead of having water kefir and kombucha going, I choose the faster water kefir. I also cut back on sourdough baking since it’s not a great time to be running the oven. Finally, I don’t actually ferment a lot of vegetables throughout the summer.

Utilizing Cold(er) Storage

Some cultures can be put into a cold storage scenario in order to slow down their fermentation. Sourdough and milk kefir, in particular, are two that I like to throw into cold storage when I know I won’t be getting to them in time.

If refrigeration doesn’t work for you, a root cellar, cold basement, or man-made hole in the ground with a cooler sunk in will at least slow down the process.

Forgoing Vegetable Fermentation in the High Heat

We aren’t exactly bringing in wheel barrels of produce from our gardens yet, but because of the heat and our lack of a root cellar, I have made a conscious decision not to ferment vegetables during the summer.

Instead we are growing vegetables for fermentation in our fall garden and I will be fermenting those, if they come to fruition, in the cooler November & December temperatures.

So, that’s how I’m dealing with the heat. How about you?


Shannon is a mama to four small children, homesteader, freelance writer, and picture-taker. She lives with her husband on their off-grid homestead where they make and eat kefir, kombucha, sourdough, and fermented vegetables.

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  1. Tiffany says

    We have air conditioning in our bedroom set at 78 degrees, so I moved our fermenting vegetables and milk kefir to the bedroom. We had a slight problem, when our pickles and sauerkraut started fermenting and leaving an odor…not a bad odor necessarily, but not really something you want your bedroom to smell like. We couldn’t really place the smell, so we started searching for dirty socks and considering that we might have a mildew issue. When I removed the kraut and pickles (which turned out wonderful in the cooler temps) the odor was gone as well. I will try to remember that next week when I start kraut and pickles all over again!

  2. David says

    I think it is possible to use any old small refrigerator. Perhaps with external digital precise thermostat in order to better control the temperature.?

  3. Linda says

    Hi I live in Cocoa beach Florida. Right now the temperature outside has been about 84 daytime and 75 nighttime. I bought some pickl-it jars so I can make saurkraut for medicinal purposes. I don’t care if it crunchy or super tasty, just want lots of good bacteria to form in it. I have a salt issue so going to be using a little less than half the salt recommended. My problem is that we keep our house around 76-79 in the day time and 76 at night. Can someone tell me how many days/weeks it will take to get a bunch of good bacteria in the jar?..I’ve spent months and months reading about fermenting but am concerned about making it properly since I will be reducing the salt. Thanks to anyone that can give me some advice from personal experience! :-))

    • says

      Linda – I’m afraid it is quite difficult without scientific testing to say exactly when the bacteria are at their peak in a ferment of any kind. We do know that using less salt and warm temperatures will increase the rate of proliferation of the bacteria, however, so we could take a guess. I would also look for signs that the earliest stages of fermentation have passed: carbon dioxide production is slowing down, the kraut no longer looks as plump as a fresh vegetable, etc.

      Given those thoughts I would give it 3-4 weeks at least and then taste it. I often find that a very lively kraut gives me a certain vibrancy which is a good indicator of plenty of bacteria and enzymes.

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