What is a SCOBY? How does it make kombucha? What are first and second fermentation processes? How do they affect the taste? Let us delve a little deeper into the science behind a yummy glass of kombucha. Also, check out cocktail ideas at the bottom.
We know that kombucha is yummy, fermented tea made with a starter culture (SCOBY), tea (black/green/oolong) and sugar; it contains vitamins and good gut bacteria to keep us healthy and happy. But to make a good batch of kombucha, we need a good SCOBY and create a good environment for the SCOBY to live and flourish.
What is SCOBY?
- Acronym for "symbiotic culture of bacteria and yeast"; in its most common form, it is gelatinous, cellulose-based biofilm or microbial mat found floating at the container's air-kombucha interface. The consolidated layer is known formally as a pellicle.
- SCOBY bacteria are acidophiles, meaning that these bacteria thrive in acidic environments.
- Composition of microorganisms in the SCOBY are highly variable but most common strains includes:
- Aerobic bacteria like Gluconobacter and Acetobacter. SCOBY contains up to 30% Lactobacillus. Acetic acid bacteria are also responsible for the formation of the cellulose layer.
- Yeast species like Schizosaccharomyces pombe, Brettanomyces bruxellensis, Saccharomyces cereviseae, and Zygosaccharomyces rouxii.
- Zygosaccharomyces has been found at levels above 90% in most SCOBY samples.
How does SCOBY help in fermentation?
- First step: yeast in the SCOBY ferments the sucrose in the initial sweet tea into glucose and fructose and utilizes these monosaccharides to produce ethanol. Zygosaccharomyces is reported to be involved in 84.1% of all kombucha SCOBY fermentation processes.
- Second step: different bacteria in the liquid culture convert the ethanol into organic acids such as lactic acid or acetic acid. These processes are known as lactic acid fermentation and ethanol metabolism, respectively.
- Once the internal conditions and temperature are in place, the symbiotic mixture is left to ferment for a minimum of 10 days (longer for stronger taste); greater fermentation times correlate with higher levels of organic acids and other amino acids, which can attribute to the sour undertones of some kombucha.
SCOBY pellicles, like sourdough starters, can be used to start new batches of kombucha and continue the fermentation process. This can be attributed to SCOBYs ability to not only house the symbiotic growth, but a small amount of the previous media and product due to its ability to absorb water.
First and Second fermentation
- The above-mentioned steps are referred to as the first fermentation and sometimes the only fermentation step if you are interested in plain kombucha. Second fermentation is the process through which kombucha can be flavored, carbonated, and more!
- Throughout the first fermentation process, the SCOBY is present in the liquid and creating the healthy organic acids and other nutrients. Once the desired acidity level is achieved after 10 or 14 or more days of fermentation, the SCOBY is removed. At this stage, the kombucha is plain and ready for consumption, but most brands will now add flavor (with fruits, juice, herbs, spices, vegetables, etc.) and let the kombucha sit for a few more days.
- The first fermentation process is aerobic as the SCOBY requires oxygen to create magic, hence the fermentation vessels are usually covered with cloth. In the second SCOBY-free fermentation, conducted in an airtight vessel, the yeast remaining in the kombucha will consume most of the sugars that are added, providing a healthier product. CO2 produced from the yeast cannot escape the kombucha as it does during the first fermentation, and hence the kombucha becomes carbonated during this step.
Fun facts about SCOBY
- SCOBYs are very versatile; they can be divided to start multiple cultures or dehydrated for storage and later use. Once removed, the culture will begin to regenerate a new pellicle known informally as a "baby SCOBY." This process can be repeated multiple times for months at a time. And it all starts with one SCOBY!
- If you dry out the SCOBY, it will form a leather-like cloth called microbial cellulose, which can be dyed with organic, plant-based dyes, and used to make jackets, shirts, and even shoes. Queensland University of Technology and the State Library of Queensland have been using kombucha SCOBY to produce a workable bio-textile, called vegan leather.
- SCOBYs come in 4 different types: vintage/heirloom, Tibetan, Island Girl, homegrown SCOBY.
- Scientists have found that kombucha cloth made from dried out SCOBYs heal burns faster than gauze and cause less scar tissue. SCOBY's ability to hold more water than gauze helps keep burns moist but sterile.
After all that scientific know-how about fermentation and SCOBYs, time to enjoy some tasty and healthy kombucha. For the summer patio season, Booch has conjured up some tasty cocktail combinations for you enjoy while being mindful of your gut health.
CITRUS BOOCH MIMOSA
Pour 1/2 bottle of Citrus Twist Booch or Ginger Booch into champagne flute glass. Top with sparkling wine. Add sprig of rosemary.
MUDDLED BLUEBERRY MOJITO
Muddle 3/4 bottle of Blueberry Holy Basil Booch with 1 oz rum, wedge of lime, frozen blueberries and fresh mint. Pour into sugar-rimmed glass. Serve with sprig of mint and lime wheel.
RED BOOCH SANGRIA
In glass pitcher add 1 bottle of Chaga Chai Booch to full bottle of red wine, 1 cup orange juice and 2 oz orange liquor. Add sliced oranges, apples and lemons. Serve in large wine glass. Garnish with ice and orange wheel.
GIN BOOCH SANGRIA
In glass pitcher add 1 bottle of Old Fashioned Booch to 1 litre of lemonade. Add 4 oz gin and 2 oz orange liquor. Add sliced cucumber, strawberries, fresh mint, and oranges. Serve in tall glass with cucumber wedge.
BOOCH BEER RADLER
In a frosted pilsner glass add 1/2 bottle Old Fashioned Booch and top with favourite Saison or IPA. For a fruity version substitute Old Fashioned Booch with Raspberry Lemonade Booch.