Yogurt cultures are nearly invisible. You start with either some cloudy milk or a powdered version of this. But authentic kefir, kombucha, and ginger beer are made with a permanent mother culture, which we will call a SCOBY. The term SCOBY stands for symbiotic community of bacteria and yeasts. A SCOBY is large enough that you can see it, handle it gently, and move it to wherever you need the culture.
Each SCOBY is an amazingly stable and diverse community of organisms. These bacteria and yeasts are the original probiotics of our ancestors, handed down for thousands of years from generation to generation. There are some variations between the different SCOBYs, but research has revealed that each kind tends to contain some of the same beneficial species of yeasts, lactobacteria, and aceto acid bacteria. Once you have a SCOBY, you can keep maintaining it indefinitely, as our ancestors have done. And you can use it to culture any food or drink in this book, plus many more.
To culture a drink, you simply put the proper SCOBY in it. In a matter of hours or days, your drink will ferment. You just need to include the proper ingredients and keep it in a still place until your probiotic drink is ready.
Each kind of SCOBY is accustomed to feeding on (and thereby fermenting) particular foods. For example, kombucha SCOBYs (known as “kombucha mushrooms” or “the kombucha mother”) have been developed to ferment sweet tea. Brew some tea, add some sugar, and the kombucha cultures will thrive. Similarly, kefir grains (which resemble small milk curds) contain a high proportion of lactobacteria. Since these species can metabolize lactose, they are great for fermenting milk.
Water kefir grains are virtually identical to dairy kefir grains except that they normally appear translucent rather than white. Water kefir grains were developed to culture sugar water or juice. The lactobacteria can metabolize sucrose (table sugar), while the yeasts are well suited to breaking down the fructose in fruit juice. In both cases, simple sugars, which the organisms can eat as they ferment your drink, are left over. The ginger beer plant (or “ginger beer mother”) is another SCOBY that has been developed to make naturally fermented ginger beer from water, sugar, and ginger.
You can use SCOBYs to culture solid food dishes also, from sauerkraut to cottage cheese. There are two options for this. First, you can put some of the SCOBY culture into whatever food you want to culture (such as putting kefir grains in some shredded cabbage to make sauerkraut). Second, you can simply pour off some cultured fluid from the SCOBY. For example, a few tablespoons of kombucha or water kefir contain enough of the starter culture to ferment any of the solid food dishes in this book. If you use fluid as a culture rather than the SCOBY itself, you probably will get a more uniform and even fermentation. Also, you will not have to go digging through your fermented food to find pieces of the SCOBY and pull them out again. But either method works fine.
To maintain your SCOBYs, you need to continue feeding them regularly. This basically consists of keeping them in a drink that includes whatever they like to eat (milk, sugar water, etc.). You need to keep adding more every few days. If you stop feeding them, they will die, and you will need to start again with a fresh SCOBY.
If you need to take a break from fermenting, you can store your kefir grains in the refrigerator in some milk/sugar water. This will ferment in the refrigerator, but quite slowly, as the organisms’ metabolism slows way down in cool temperatures. You can store the SCOBY grains like this for up to two weeks at a time. If you need to store your culture longer, then change out the fluid and replace it with some more milk or sugar water. For kombucha SCOBYs, it is best not too refrigerate because the yeasts can go dormant and take a while to awaken later, which throws the culture out of balance. Just keep the mushroom going in a room-temperature drink, even if you do not plan to drink it. Kombucha drinks take a while to ferment anyway, so you probably can fit in a vacation for a week or two.
