It's best to begin with one litre. When the Kombucha culture has grown big enough and has reproduced itself, you can produce larger quantities of the drink.
- Make tea in the ordinary way. Per litre of water, soak 2 teaspoonfuls (about 5 grams) of black or green tea in freshly boiled water. You may also use tea bags. Let the tea leaves "boil" for 10 minutes. Do not use herbal teas.
- Add about 3-4 tablespoons (60 - 80 g) of white sugar per litre of water before it has cooled. Stir the tea so that the sugar dissolves totally.
- Strain off the tea leaves through a sieve, or remove the tea bags from the water. Let the sugared tea cool down to room temperature or lukewarm. The culture dies when it has been placed in a hot nutrient solution.
- When the tea has cooled to room temperature, pour the solution into a glass, china, glazed earthenware or stainless steel container. Glass is best. Metal containers of other types than stainless steel are unsatisfactory and should never be used because the acids formed may react with the metal. Avoid containers made of plastic.
- When preparing your first Kombucha drink, add the liquid that you got with the culture. On all later batches, always keep enough Kombucha drink to add about 10% of the quantity to your new batch as a "starter liquid".
- Place the live Kombucha culture in the liquid that contains the freshly brewed tea and "starter liquid".
- Cover the mouth of the fermentation container with a tightly woven fabric, a tea towel, paper towel or similar light cloth to keep out fruit flies, dust, plant spores and other pollutants. Tie it down with a large rubber band to ensure that fruit flies can't get in. The cloth must be porous enough to allow air to circulate so the culture can breathe, but not so porous that tiny fruit flies can get in to lay their eggs.
- The fermentation should continue for 7 - 14 days, depending on the temperature. The higher the room temperature, the faster the fermentation. The period of 7 - 14 days is given merely as a guide. The Kombucha culture needs a warm and quiet place and should not be disturbed or moved. The temperature of the tea should not fall below 20°C. The ideal temperature is about 23° - 29° C. Light is not necessary. The culture also works in darkness. The culture may be damaged by exposure to bright sunlight. Half shade is better.
- During the process of fermentation the sugar is broken down by the yeast and converted into a gas (CO2) and various organic acids and other compounds. It is the combination of these processes which gives the Kombucha beverage its characteristic flavor. The mixture is at first sweet but this sweetness disappears as the sugar is broken down. At the same time an acid flavor begins to develop as a result of the activities of the bacterium, so there is a transition from sweetness to sourness. If a slightly sweet drink is preferred, the fermentation has to be stopped earlier. For a dry or slightly acid flavor it has to be continued longer.
- When the tea has attained the right acid degree (pH 2.5 – 3.5), depending on individual taste, remove the culture with clean hands. Clean the culture under cold or lukewarm water. Keep aside 10% as starter for the next batch. Place lids on bottles. It is not necessary to strain the fermented beverage through a cloth. A certain amount of sediment is normal. It is due to the growth of yeasts, which produced the gas which aerates the beverage. The yeasts are said to have some desirable positive effects on the human organism.
- To find ultimate satisfaction in this drink it should be allowed to mature for a few days (at least 5 days), after having been bottled. The activity of the bacterium is stopped because the bottling excludes the air, while the yeast continues to work. If the lids of the bottles are securely tightened, the gas produced by the yeast's activities, is unable to escape. Thus an effervescent drink is produced. For this a few days in the bottles is usually sufficient; the Kombucha beverage, however, will keep well for months. Do not worry: The yeast will stop the gas production at a certain point. It is advisable to keep the beverage in a cool place.
- The drink has an agreeable taste. It is sparkling, slightly sour and refreshing. One normally drinks three glasses a day, one glass (250ml or more) on an empty stomach in the morning, the second glass after a meal in the course of the day, and the last glass a short time before going to bed.
- When you start a new fermentation process, never forget to add to the new tea at least 10 % of the liquid from a cultivation which has already fermented.
Sometimes the culture floats on the surface, sometimes it sinks to the bottom of the liquid. Both is OK. When the culture sinks to the bottom a new culture (a baby-culture) will begin to grow on the surface of the tea. The Kombucha culture needs some time to reproduce itself. It begins with a thin and filmy layer. The longer you leave it in peace, the thicker the new culture will grow.
The Kombucha culture grows and covers the surface of the tea completely. While growing on the surface of the tea the culture thickens considerably. The thickened culture will be composed of easily separable superimposed layers. The layers can be peeled off one from another and each can be used as independent units for the production of Kombucha beverage. If the culture should sink to the bottom of the vessel, a new culture will form on the surface of the tea.
In this way each culture will continue to propagate itself until it gradually begins to turn a dark brown color. When it is dark and dirty brown discard it and replace it with one of its offspring. Thus this unique culture can provide you, your family and your friends with an ongoing supply of Kombucha tea at very low cost.
Three main signs of a healthy ferment:
1. A smooth film growing on top
2. No fuzzy, dusty or colorful culture
3. A slight vinegar aroma
If any of the above takes place, we recommend throwing it out and starting over. Mold can cause illness, especially if the person is allergic to molds. Usually though, the main symptoms from eating moldy food will be nausea or vomiting from the bad taste and smell of the moldy food. When in doubt, throw it out and start over.