How To Grow A Kombucha SCOBY From Scratch

There are many reasons why you might need to grow a kombucha SCOBY (Symbiotic Colony Of Bacteria and Yeast) from scratch.

You’re new to brewing and don’t know where to buy a SCOBY. You can probably find a source for kombucha brewing supplies, including SCOBYs, by asking at a gardening and DIY store, or a shop that specializes in equipment for making homemade beer or wine. You can also look for community college classes that focus on natural and traditional foods, many of which are fermented.

You live in a location where getting a SCOBY by mail is impractical. The SCOBY culture is fairly hardy, but doesn’t deal well with extreme temperatures, so if you’re trying to start your new kombucha homebrewing routine in February and you live on a remote farm in northern Minnesota, you might have problems with shipping and delivery.

There’s no one else in your area who’s making kombucha (unlikely, but possible). More and more people are getting into homemade food and crafts, so most communities have at least one group where people get together and share techniques on making things like pickles or cheese, or growing organic vegetables, or keeping chickens in the back yard. Even if no one is making kombucha, you can start networking to get new places to look and people to talk to.

You want to make sure that only quality organic ingredients are involved. Several of the best online sources for SCOBYs and other kombucha brewing supplies use organic ingredients, but if you’re not sure about the quality, you can grow your own and be confident that you know exactly what’s going into your brew.

You are completely out of usable SCOBYs. If you’ve accidentally dropped your SCOBY hotel  on the pantry floor and now every single one of your SCOBYs is full of dust and broken glass, you’re going to have to start over.

Fortunately, SCOBYs are easy to grow, even when you’re starting from scratch. All you need is water, sugar, tea leaves, and a bit of starter liquid from a previous batch of kombucha.

NOTE: No one knows where the first SCOBY came from, but the only way to reliably get a SCOBY today is by encouraging the growth of the yeast and bacteria in kombucha tea to form a colony. Don’t try to make a “natural” SCOBY by letting plain sweetened black or green tea leaves ferment, because you’ll just end up with moldy tea leaves.

What You’ll Need to Grow a SCOBY From Scratch

First, you need your starter liquid. Here are your options, with the best choice listed first:

•  Use concentrated kombucha from a SCOBY hotel. If yours is in pieces on the floor, see if you can get at least half a cup from someone else who’s currently making kombucha. This liquid is full of the yeasts, bacteria, and nutrients that will quickly form a SCOBY, and it’s also highly acidic, which will protect the new SCOBY as it grows.
• Use fresh kombucha tea that you or someone else has made. Be sure that this is plain kombucha without added flavors or ingredients, which will affect the new SCOBY and may even prevent it from growing. Ideally, the kombucha tea should be less than a week old.
• Use store-bought kombucha. This needs to be unpasteurized kombucha (i.e. “raw”) that has no added ingredients or flavors. If you use pasteurized kombucha, you may not end up with a SCOBY because the many of the natural yeasts and bacteria in the kombucha have been killed off in the pasteurization process.

Next, you need to make the sweetened tea that will nourish the yeasts and bacteria as they multiple and congregate to form the new SCOBY.

Follow these tips for the best results :

• Use unflavored black or green tea, either in bags or as loose-leaf tea (see our best tea for kombucha post). Get the freshest tea leaves you can, and look for organic tea if possible.
• Use evaporated cane juice or another minimally-processed white cane sugar (see our types of sugar for kombucha post). The microorganisms in the SCOBY grow fastest when they have simple sucrose/glucose sugars to eat, and using sweeteners that have a high mineral content (like brown sugar) or contain low levels of glucose (like honey) will slow down the development of the colony.
• Use filtered water to make the tea (see our what’s the best water for kombucha brewing post). Distilled water is another option. You can also boil tap water for 20 minutes to remove chlorine and other compounds that are generally added to the water supply in any town or city.

Use the Right Proportions

When you’re making kombucha tea to drink, you can adjust the ratio of ingredients for kombucha brewing depending on the type of ingredients you’re using and the results you want. However, when your focus is on growing a SCOBY, stick to these measurements:

• 4 cups of water
• 2 teaspoons of tea leaves (2 bags)
• 1/2 cup of sugar
• 2 cups of starter

This ratio gives you the right pH level, and a liquid that is acid enough to prevent the growth of foreign bacteria and mold while the SCOBY is developing.

Get Brewing

Boil the water and pour it over the tea in a clean heatproof container (glass is the best material for brewing kombucha). Let the tea steep for at least 10 minutes. Remove the tea leaves or tea bags and stir in the sugar until completely dissolved. Do not use a metal utensil. Let the liquid cool until it reaches room temperature (below 80F but above 60F).

If you used a glass container to make the tea, you can simply stir in the starter, cover it, and let the kombucha start to ferment. If not, pour the cooled liquid into a clean jar or bowl before adding the starter. Cover the container with a clean cloth that’s thick enough to keep out dust and bugs, but thin enough to let the kombucha breathe. You can use a piece of a t-shirt, a linen napkin, a cotton dishtowel, or even an unbleached coffee filter (basket style, not cone). Use a string or rubber band to secure the material tightly around the edge of the container.

Put the container someplace out of direct sunlight, where you can let it sit undisturbed for up to a month (though it might not take that long for the SCOBY to develop). The container needs to stay between 60-80F at all times for the best results.

Monitor Your SCOBY

In a day or two, you should be able to see a thin clear film forming on the surface of the liquid. You might see bubbles on the underside of the film. This is the new colony, and the bubbles are the carbon dioxide that the microorganisms are producing as they eat the sugar in the tea. It will take a week or longer for the new SCOBY to get thicker and turn opaque. The color of a healthy SCOBY will be a very pale yellow or creamy white.

If you have the temperature and the acidity right, and you’re protecting the container with a cloth covering, you shouldn’t have to worry about mold growing on the SCOBY.

The thicker the SCOBY is, the better results you’ll get when using it to brew kombucha tea. If possible, let your new SCOBY grow until it’s at least 1/8 inch thick, and 1/4 inch is even better. This can take up to 30 days, so don’t be impatient. Once you have a good healthy SCOBY, every new batch of kombucha will create another SCOBY, so you shouldn’t ever have to grow a SCOBY from scratch again. Just be careful when you’re taking that SCOBY hotel out of your pantry!