Ferment it Yourself (With a Little Help From Local Shops)

kombuchaIllustrations by Lauren Costa.

Sure, you can show up to that holiday party with a bottle of wine or a cheese platter—but a year from now, who’s going to remember what you brought? Here’s something everyone will remember: if you arrive with something you fermented yourself.

Fermentation is a fairly intuitive process—it’s not nearly as intimidating as it might seem. With the right parameters, you can turn cucumbers into pickles and flour into sourdough. Even coffee and chocolate require fermentation. We asked local writer Kendra Long, who’s worked in restaurants for more than eight years and knows a thing or two about a pickle, to round up three at-home fermentation projects that are easy enough for beginners and guaranteed to leave a lasting impression.

By Kendra Long


Arguably the lowest-maintenance project for a first-time fermenter is kombucha. Its exact history and origins are a little hazy, but the first written occurrence of the name is from Japan in 415 AD. References to a similar drink date back to China’s Tsin dynasty in 212 BC. Kombucha is great because it requires no babysitting or regular feeding. Just put your ingredients together and check sporadically for progress. Otherwise, it’s a set it and forget it sort of affair.

To start, you’ll need a SCOBY, a symbiotic colony of bacteria and yeast. You can brew your kombucha using an established SCOBY, which you can obtain at Cambridge Naturals, through Craigslist or even from Facebook groups. Or, you can start your own SCOBY from scratch, either by buying a kit or a pre-made bottle of kombucha.

If you have an established SCOBY:

1. For a 2” x 2” SCOBY, brew six cups of tea. Strength and flavor are up to you—I really like Earl Grey, but any black, green or white tea will do. Add one cup of white sugar. Let cool to room temperature.

2. Pour the tea into a jar large enough to hold all of it and add your SCOBY. Put on a tight lid and leave it somewhere warm and dark to ferment for about a week. Taste after a week. If it’s too sweet, let it hang out for another week or so. A white disk on the surface is normal—that’s your yeast! But if you see a lot of mold, throw it out and start over.

3. Once it’s suitably tangy, sour and bubbly, strain off the majority of the kombucha, refrigerate and enjoy. Depending on ambient temperature, this could be up to a month, so be patient!
To store the SCOBY (which by now should look like a slimy pancake—yum!), cover it with kombucha and store it in a glass container with a lid in your fridge. To use it again, just let it come to room temperature, and once again feed it a sweet tea mixture.

If you don’t have a SCOBY:

Buying a kit is going to be the easiest way to do this successfully, and you can find them at local shops like Modern Homebrew Emporium. If that’s not of interest, you can make kombucha from a bottle of kombucha you’ve bought—local shops like Cambridge Naturals have kombucha on tap—provided your bottle is raw and not pasteurized.

1. Brew a cup of tea, adding 1-2 tablespoons of sugar. Let cool completely.

2. Pour your sweet tea into a glass jar, along with a bottle of raw kombucha. Make sure any bits of SCOBY—sometimes called mother—make it into the new jar. They’ll look like translucent slimy strings near the bottom of the bottle.

3. Cover with a dishtowel and secure in place with a rubber band. Leave in a warm, dark spot for about a month, checking weekly for yeast (which is good!) or mold (which is bad!). Your SCOBY should start to form. At first, it will look like a thin white or clear film on the top, eventually growing thicker and more opaque.

4. If, after a month, you have nothing—or if you have mold or a horrible rotting cheese smell—throw it out. Your kombucha could’ve been too weak to propagate, the container could’ve been contaminated, the planets could’ve been misaligned—there are a lot of reasons this can happen. In general, it’s better to start over than try and fix your failed ferment.

jeremy oguskySOURDOUGH

Here’s the simplest way to think about sourdough: It’s not a type of bread, but it’s a type of yeast used to make bread. Dried yeast from the grocery store is really just a replacement for what sourdough starter has done for millennia. Starter itself is also fairly hearty—Boudin Bakery in San Francisco has been using the same starter since 1849.

Because almost every flour-consuming culture on Earth has a sourdough recipe, I’ve chosen to focus on two: one that Boudin favors that’s somewhat standard in American bakeries, and one that’s more common in Italy. They’ll yield tasty bread either way, and making both can be a good learning opportunity!

Biga, or Italian Grape Sourdough Starter

1. Stem 1/2 pound of organic red grapes, wrap in cheesecloth and knot shut to form a bag. Crush.

2. Combine 2 cups of bread flour and 2 1/2 cups of water (filtered, or boiled and cooled water is ideal, as tap water’s chlorine content may inhibit yeast growth). Add the grape bag to the mixture, and make sure to submerge it.

3. Cover tightly with a lid, or plastic wrap and a rubber band. Stir daily. Once the starter is yellow and smells somewhat sour, squeeze the liquid from the bag into the mixture, discard the bundle and transfer the starter to a clean container. Refrigerate.

Boudin Starter 

Where biga relies on yeast from the grapes to start the process, it is also possible to just add flour to water and feed yeast already present in the air. The tricky part is it can be a much slower process.

1. Add 40 grams of flour to a jar. Add 40 grams of filtered (boiled and cooled) or bottled water. Stir well. Cover with a kitchen towel. Let sit in a warm part of your kitchen overnight.

2. The following day, remove all but 40 grams of the starter. Add 40 grams flour and 40 grams water, stir well, cover and leave for the following day. Repeat this for a week.

3. The starter should start to become more bubbly as time goes on, and take on a somewhat sour smell. If water seems to be pooling on the top, reduce the water content slightly or up the flour content with each feeding. If at any point there’s a rotten smell, mold or a pronounced red tint, it’s best to throw out and start over.


Kefir is a yogurt-like drink that traces its origins back to the North Caucasus mountains, in the area between Georgia and Russia.

Of the three types of fermentation featured here, kefir is the most labor intensive. Every 12 to 24 hours, it has to be strained and refrigerated, lest you starve your grains and create a curdled yellow nightmare on your countertop.

Starting with established kefir grains:

1. Put 1-2 teaspoons of active kefir grains and 4 cups of milk in a glass jar.

2. Cover with a coffee filter and secure with a rubber band.

3. Let sit at room temperature for about 24 hours.

4. Strain out the kefir grains, either with a plastic or stainless steel strainer.

5. Put the finished kefir in the fridge, and put the kefir grains into fresh milk to begin the process again.


As with kombucha, one can start with a kit or with grains from a store, but it is possible to make from a bottle of store bought kefir.

1. Mix 2-4 tablespoons of kefir into a quart of room temperature milk. Let stand for 12-24 hours, until thickened.

2. Refrigerate and enjoy.

3. Save 2-4 tablespoons from this batch to add to the next batch. Because there are no grains, this will be somewhat of a finite process. If, on the second or third use, the milk hasn’t thickened after 24 hours, your kefir was probably exhausted and the milk should be tossed out.

This story originally appeared in the November/December issue of Scout Cambridge, which is available for free at more than 250 locations throughout the city or by subscription.