I usually take on one new hobby per break. This winter break, I happened to get super into fermenting.

I’d already experimented with kombucha, yoghurt, and simple pickles in the past, but suddenly my parents found our kitchen at home this winter full of bubbling bowls and jars and crocks (my fault entirely).

Now that I’m back in Ithaca I’ve committed to experimenting seriously with kombucha, sauerkraut, sourdough, and home-brewed beer.

The beautiful process of fermentation is dependent on the variety of healthy bacterias and yeasts in our home environments. When lactobacillus, the bacteria on the vegetal surfaces, consumes sugar in cabbage it produces lactic-acid in turn protecting cabbage from harmful bacterias. Lactobacillus also helps acetobacillus and wild yeast to ferment sugars in dough, which in a few days develops into a complex and nuanced sour flavor.

Kombucha and beer require the introduction of specific cultures and yeasts. To make kombucha, a brewer adds a premade kombucha SCOBY (symbiotic culture of bacteria and yeast) to a large, open mouthed vessel of sweetened black tea. In a week, during the first fermentation, the bacteria and yeast convert the sugar in the tea to gluconic and acetic acid. Similarly for beer, after adding hops and yeast to a sugary liquid from malted grains called wort the mixture ferments for a week in a bucket. The time allows the yeast to feast on the sugar and turn the concoction into a palatable alcoholic beverage.

After the first fermentation of kombucha and beer, brewers typically subject their mixtures to a second fermentation to continue developing flavor and add carbonation. The initially fermented beer or kombucha is transferred to a smaller, anaerobic container while bacteria and yeast feed further on the remaining sugars.

At this point, the risk of a huge mess looms. A sealed container with ambitious yeast and bacteria, which are constantly converting sugar into carbon dioxide, can cause explosions — soaking the floor of your dark closet in sugary, stickiness.

Brewers address this problem with two techniques: burping their bottles and using airlocks.

During the second ferment it is common for someone making kombucha to daily check their bottles. As they notice the caps bowing outward with pressure, they untwist the cap just enough to let the pent up gas out, and then tightly screw the cap back on.

A tool designed for the same purpose, an airlock is attached to the cork in a jug of beer. Pressurized CO2 pushes up a cap inside the outer airtight chamber, allowing out only the pressure that needs to be released to keep the jug from exploding. The airlock maintains a balance of release and pressure, while also protecting the beer from aggressive or harmful outside bacteria.

And here I will — finally — make the connection to violin teaching. [Read more…]