Amy Costa of Truro got into fermentation kind of accidentally. She had just stopped working as a bartender but wanted to keep creating drinks and her friend was brewing kombucha from a kit.
"If you have any starter knowledge of kombucha, it's a friendly communal beverage because those SCOBYs just keep reproducing all the time. And before you know it, you've got SCOBYs coming out of your ears," Amy said.
Scoby stands for symbiotic colony of bacteria and yeast, and these micro-organisms are the engine that make kombucha fermentation happen. We don’t know how the first kombucha scoby came to be — some people hypothesize that an insect introduced acetic acid-loving bacteria into a cup of sweet tea — but whatever took place, people liked the results. Since then, kombucha makers have been sharing the floating mats or pellicles that their scobys create — they look kind of like a weird tan blob of soft jello and they make a new one every time you brew a batch — which is why Amy’s friend was so eager to give her one.
"She shared one with me, and then before I knew it, I had multiple jars going, and once I got into the kombucha and the flavoring of it and everything, it was just so much fun."
The way kombucha works is that there are two steps to fermentation. For the first step you brew sweet tea — black or green tea with sugar — and add a little bit of kombucha from a previous batch and a scoby mat or pellicle to get the fermentation started. The tea needs to be acidic and sweet enough to create the environment the scoby organisms like, and they also have one other surprising requirement.
Amy said you have to be careful to use only black or green tea, because it consumes the caffeine that’s part of the food for the beast.
So you can’t make caffeine-free kombucha. The bacteria and yeast in the scoby feed on the sugars and caffeine in the tea and break them down into acids, carbon dioxide, and small amounts of alcohol. At this point, you can drink the kombucha as is, or you can add fruit to kickstart a second round of fermentation. Amy says playing with flavorings at this stage is what got her hooked.
"Instantly I knew that I wanted to use things that I could find locally and forage. And so Blackberries were some of the first things I did. Cranberries from the dunes. Yes. And I really love beach plum kombucha, it’s so good, I think the additional yeast on it gives it something that is just delicious, and then in that same vein concord grape is also great."
This is because fruits that have a white bloom on their skin — think any kind of plums or grapes and often blueberries and apples — are coated in wild yeasts that add to the fermentation’s vigor and flavor — and fizziness.
"Some people flavor it by, they put it in the bottle that they're going to drink it out of and put whatever chunks of fruit or squeezed fruit juice whatever into the jar and seal it. But that's a little bit of a scary game because depending on how warm things are and how much the sugar content is of your flavoring agent, you can have some explosive activity."
Basically, the CO2 content can build up so much that the bottles break. Happily, there are lots of different ways to avoid this — you can do the second ferment with a cloth on top, like Amy does, or put closed bottles in the fridge to slow the fermentation down. And most importantly, Amy says, you can see starting to ferment as a learning process — one that evolves over time.
"The more you do it, the more you'll trust yourself, the more you consume what you're making and you're fine, then you're like, I got this. I can do it."
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Here's a link to the basic process: https://kombucha.com/blogs/tutorials/primary-fermentation-f1-brewing-instructions
And here's Amy's description of her favorite kombucha flavor:
"Jesse Ceraldi [of Ceraldi's restaurant in Wellfleet] came up with this, because we were brewing with them for a while: corn, blueberry, and basil. It was so good, and so summery. It's fantastic."
