Use a wild-fermented ginger bug to add fizz to homemade soda

"The way that sourdough starter might leaven bread, a ginger bug can give homemade sodas their fizz and their bubbles," says Jennifer McGruther, author of The Nourished Kitchen.

Sally Swift: Tell me about this ginger bug recipe.

Jennifer McGruther Photo: Kevin McGruther

Jennifer McGruther: Ginger bug is a traditional way of fermenting sodas. It is a wild ferment, which means it takes advantage of all the wild yeast and bacteria that exist naturally in your home. It's essentially a slurry of sugar, ginger and water. That combination helps to promote the proliferation of beneficial bacteria and wild yeast.

It functions a lot like sourdough starter. The way that sourdough starter might leaven bread, a ginger bug can give homemade sodas their fizz and their bubbles. It's a really remarkable way to make homemade sodas.

SS: It's almost like kombucha in a way, the sweetened tea that you ferment. But you usually add a mother to kombucha. The ginger bug becomes its own bacteria, correct?

JMG: That's correct. Kombucha is a fermented tonic very similar to homemade soda, except that a kombucha relies on a SCOBY, a symbiotic colony of bacteria and yeast, to give it its bacteria. Whereas a ginger bug is a wild ferment, so it relies on the bacteria and yeast that exist naturally in your environment -- on your hands, on your cooking utensils -- to inoculate the slurry of ginger and sugar with the bacteria that will eventually make your homemade sodas fizzy and fermented.

SS: How do you go about making your own ginger bug?

McGruther's Recipe: Wild Yeast and Ginger Starter for Homemade Sodas

JMG: It's very easy to start. Fortunately, you only need two ingredients: fresh ginger and whole, unrefined cane sugar (although white sugar will work as well).

Essentially, you take a knob of ginger and you grate it until you have about 2 heaping tablespoons. Then you combine that with 2 tablespoons of sugar and 2 tablespoons filtered water. It's a really easy recipe to remember.

You let that sit on your countertop. Every day for about 5 days -- and again, because it's a wild ferment, it may take more or less time depending on your kitchen and your environment -- mix an additional 2 tablespoons ginger, 2 tablespoons sugar and 2 tablespoons water into your jar.

Eventually, this will create an environment that allows beneficial bacteria to proliferate. That will be your ginger bug.

SS: I'm assuming you leave it uncovered, because if you cover it, the bacteria is not getting in. Is that correct?

JMG: The bacteria will get into a covered environment. However, you want to make sure that it's not an airtight environment in this case. One of the best ways to cover it is actually using cheesecloth. That will allow the ferment to breathe essentially, which attracts wild yeast.

SS: How do you use it?

The Nourished Kitchen

JMG: Once you have it nice and bubbly -- again, this takes about 5 days -- you'll notice that it takes on a yeasty smell, similar to beer brewing. That's the bacteria and yeast doing their work.

At that point, you strain off about 1/4 cup of the liquid, mix that into sweetened tea, fruit juice or a combination, and then you pour it into a flip-top bottle or mason jar and secure that tightly. At this point, you want it to be airtight because that is what's going to set the bubbles. Let it ferment for about 3-5 days after that.

If you're using a mason jar, make sure to burp it from time to time to prevent over-accumulation of carbon dioxide and other gases.

SS: Or it's going to blow?

JMG: That's something you should be careful of. It's unusual to have homemade ferments like kombuchas, ginger ales and the like explode, but it does happen, depending on how hot your kitchen is. Again, it's a very, very rare event, but that's why you want to burp the jar.

[Editor’s note: In Jennifer McGruther’s original post about making a ginger bug, she links to bottles manufactured by EZ Cap. Some commenters on this story page have noted that flip-top bottles can explode. Always follow manufacturers' instructions and use caution when fermenting at home. Here are some tips for DIY fermentation, as well as more information about using and maintaining flip-top bottles.]