Culturing in the Cold

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If you make foods like sauerkraut, kefir and kombucha, chances are you've noticed a change in the way your foods culture during the winter. Cooler indoor air temperatures can slow the growth of  the bacteria and/or yeasts. Optimal temperatures vary, but most microbes enjoy what we enjoy - in the mid 70s to 80. I don't know about your house, but our house frequently goes below 70 degrees in the winter.

Before I discovered the technique pictured above, I noticed a much sweeter taste in my water kefir, letting me know that my grains were struggling. I had two choices - either lengthen the time of fermentation, or increase the temperature. I added the heating pad and my water kefir has returned to its usual tang.

Since my heating pad is new, the lowest setting works best. Older heating pads may work best at the medium or high settings. I ordered one without the automatic shut off since I don't want to worry about keeping it on. I found mine here.

(I like keeping a heating pad on my kitchen counter for another reason. It facilitates easy melting of my coconut and red palm oils, since they harden during the winter.)

A heating pad isn't the only solution for culturing during the cooler months Other options include:
  1. Increased elevation.  If you have a higher shelf in the kitchen, the yeasts and bacteria will enjoy the warmer spot.
  2. Oven light.  Some oven lights reach a temperature that is too high. Check yours before trying this method. If the temperature is not too high, this can be a great method.
  3. Seedling mat. These work similarly to the heating pad, offering warmer temperatures under the jars. 
  4. Dehydrator. You can place the jars next to a dehydrator that is in use or try putting the jars inside the dehydrator. Again, check the temperatures to avoid overheating.

Wondering about cross contamination with all of your ferments in one small location?  In his book, The Art of Fermentation, author Sandor Katz addresses the issue,

" I cannot guarantee that cross-contamination among cultures is impossible, but it is not a likely occurrence,and I encourage enthusiastic experimentalists to ferment to your heart's content with out worry of cross-contamination."

With these simple temperature control suggestions why not ferment to your heart's content this winter?

This post shared on Healing with Food Fridays