Keeping the Kombucha Brew Warm

It's been a pretty cold and snowy winter this year in Boston, and because the house that I'm currently living in is on the chilly side, I finally decided to purchase a seedling mat for my brew!

Ideally, kombucha brews at around 74 - 84 degrees F. According to Happy Herbalist, the warmer temperatures produce a "faster more consistent ferment while the lower temperatures produce a less harsh more mellow taste though more inconsistent and with a greater susceptibility to molds and pathogens forming. Kombucha brewing seems to work better in the summer than in the winter months."

I agree that kombucha brewing works much better during the summer months than in the winter. So to keep my kombucha warm, I purchased this seedling mat from Amazon. The mat, which you plug into an electric outlet, is supposed to warm the area about 10-20 degrees F above ambient temperature. Although the kombucha and SCOBYs still don't seem to be as happy as they typically are during the summer, the seedling mat has definitely helped!

Other ideas to keep your kombucha warm:

• Brewing your kombucha in a warm (but undisturbed) location, such as in a kitchen cupboard
• Brewing the kombucha in a cabinet with a light bulb (as recommended by Happy Herbalist)
  
• Using a heating pad
  
  

What do you do to keep your kombucha warm?

Q&A: When is my kombucha done fermenting? (Updated 5-31-2010)

Q: How do you know when your kombucha is ready to drink, ready to bottle, or if it's done fermenting?

A: If you are brewing using the traditional method, your kombucha may be done at anywhere between 6-14 days. The time may even be more or less, depending on personal preference, the amount and strength of the starter tea you used, and various environmental factors, such as temperature. So how do you know when your kombucha is done? Here is a list of several signs that help to indicate when your kombucha is ready (please note that not all of these need to apply!):

• According to taste- the most important indicator, as individuals have varying preferences for the amount of fizz, the strength of the sweetness, and the intensity of the vinegar-taste of kombucha
• Hard apple cider or apple cider vinegar aroma or taste present
• The kombucha tastes slightly sour or acidic (like vinegar)
• Kombucha gets more cloudy/opaue, and thus becomes lighter in color, the longer it ferments due to yeast reproduction
• The partial/complete formation of a new kombucha baby
• Kombucha is bottled "optimally" at a pH of 2.5 - 3.5 (testing pH is optional)

Note the clearness of the kombucha at the beginning of fermentation (left) and the cloudiness of the kombucha at the end of the primary fermentation process (right). (My apologies if it is hard to tell in this photo).

Note:

• Home-brewed kombucha tastes a lot different than GT's traditional kombucha. I've found that Katalyst and High Country kombucha taste more similar to home-brews.

Factors Affecting Your Brew

photo source: http://www.happyherbalist.com/timeandtemp.aspx

I just love this chart from Happy Herbalist, which shows how various elements in kombucha tea are affected with time. As fermentation time increases,

• The acidity of kombucha tea increases
• The pH, sugar content, and alcohol content of kt decrease

With more fermentation time, the yeasts will have more time to convert the sugars → alcohol + CO2 (a waste product that is released into the air), decreasing the sugar content.
Meanwhile, the bacteria will have more time to convert the alcohols → beneficial acids, increasing the acidity, and lowering the pH and alcohol content of the kombucha.
Furthermore, the warmer the environment, the faster the kombucha will brew- which is something to keep in mind in the colder, winter months and the hotter, summer days. Finally, another factor that speeds up the fermentation process is adding more starter tea when brewing.