Safe Preserving: Kombucha: What you need to know.

kombuchaKombucha is prepared by fermenting sweetened tea with a symbiotic culture of yeasts and bacteria. The product is a slightly sweet, carbonated, acidic tea beverage. Some call it mushroom tea or “elixir of life,” but no matter what you call it, kombucha is one of the hottest trends in the beverage industry. The fermented tea drink has been around for centuries but recently became popular in the U.S. because of its purported health benefits. Regular drinkers of the tonic claim it aids digestion and sleep, prevents cancer, stops hair loss, and improves liver function. None of these health claims have been validated.

What is kombucha? Often referred to as ‘mushroom tea’, kombucha is not made from mushrooms, but the bacteria and yeast that grow on top of the beverage result in a blob that resembles a mushroom. It is made by adding the bacteria and yeast to sugar and black or green tea and allowing the brew to ferment.

According to WebMD, at first taste, kombucha tea tastes somewhat earthy, tart, with a little effervescence and a vinegar-like smell – not so pleasing to the taste buds. To make the tea more palatable, juice is added to the base brew. But if you look a little closer, you notice little floating bits of bacteria in the unpasteurized beverage. The fermented beverages are high in acid and contain sugar, vinegar, B vitamins, antioxidants (from the tea), trace amounts of alcohol (a natural consequence of fermentation), and other chemical compounds.

Homemade kombucha ferments, from a starter, in 7-14 days. Some brands are pasteurized to kill potential pathogens; other brands and most home brews are drunk raw or unpasteurized. Some experts warn about the dangers of home-brewed and unpasteurized kombucha prepared in nonsterile conditions and the risk for unhealthy bacteria getting into the tea. The U.S. Food and Drug Administration cautions that home-brewed versions are at high risk of contamination.

Food safety tips. There are no approved/tested recipes for the safe manufacture of kombucha. If you make this product at home, there are a few things to keep  in mind.

  • Sanitation is critically important. Use sterile containers and utensils during kombucha preparation.
  • Sugar must be added and sucrose (table sugar) is preferred. Bacteria and yeast feed on sweetened, brewed tea to product the final beverage. The tea must be sweetened for the microorganisms to grow and fermentation to progress. Add sugar at the rate of 1.76 ounce per one quart of tea.
  • Tea, black or green, should be the beverage base. Do not sure herbal teas or other beverage bases.
  • Heat the tea base to boiling, cool rapidly, and add the starter. Ferment at 68-72°F for 7-10 days; cooler temperatures (62-78°F) will also work. Do not ferment in the sun or outside where the temperature can rise too high.

Reference: Kombucha, the fermented tea: microbiology, composition, and claimed health effects. Greenwalt et al. 2000. Journal of Food Protection. 63:976-981.

Safe preserving! Barb