Updated October 2026

How to Brew Kombucha at Home: The Tested Recipe

The National Center for Home Food Preservation now has a tested kombucha recipe. Here it is, with the safety factors behind it.

Per gallon of water: 6 bags (3 tablespoons) of black tea or 13 bags of green tea, 1 cup of sugar, and a SCOBY with its starter liquid at pH 4.0 or lower. Steep the tea for 2 minutes in 4 cups of water at 160 to 170°F, add 12 cups of cold water, cool below 95°F, add the SCOBY and ferment at 68 to 77°F for 7 to 10 days. Then bottle, refrigerate and use within 30 days. The University of Georgia and Kansas State developed it by testing what survives.

Batch calculator

Step by step

1. Wash hands for at least 20 seconds. Wash equipment, then sanitize it in water of at least 171°F for 30 seconds.
2. Test a tablespoon of the starter liquid with a pH strip. If it reads above 4.0, do not use it.
3. Heat 4 cups of water to 160 to 170°F and steep the tea 2 minutes. Remove the tea and stir in the sugar.
4. Add 12 cups of cold water and check the tea is below 95°F.
5. Add the SCOBY and starter, stir for 10 seconds, cover with a paper towel or coffee filter and a rubber band, and date it.
6. Ferment at 68 to 77°F for 7 to 10 days.
7. Pour into clean, sanitized jars or bottles and refrigerate promptly. Use within 30 days.

Safety notes

• Do not use glazed earthenware: the acid can leach heavy metals.
• Dry, fuzzy patches on the SCOBY or the surface are mold. Discard the tea and the SCOBY.
• Airtight bottles build carbon dioxide and can explode if not monitored.
• Flavored kombucha (fruit, ginger, herbs added after fermenting) should be drunk right away or refrigerated for up to 2 days.
• Up to 4 fl oz a day is considered safe for most healthy people. It is not advised during pregnancy or breastfeeding, with a weakened immune system, or with a risk of acidosis.
• Home brews can exceed 0.5% alcohol.

Water kefir and milk kefir

There is no USDA or extension-tested water kefir recipe that we could find, so we do not give one. For milk kefir, use pasteurized milk only.

Sources we checked (October 2026): National Center for Home Food Preservation, Kombucha Tea; University of Georgia Extension Circular 1312, What's the Word on Homemade Kombucha? (2026).