Hydrometer and specific gravity readings are standard practice in brewing and winemaking. If you’re not familiar with hydrometers and how to use one, jump over to our post on how to use a hydrometer. In short, hydrometers are used to determine the density of a liquid and, ultimately, the alcohol content of your beer, wine, cider, etc. Since hydrometers are used to determine fermented beverages’ alcohol content, it’s often assumed that a hydrometer will work the same when brewing kombucha. So does it?
Can you use a hydrometer to determine the ABV of kombucha?
No, you cannot accurately determine the alcohol content of kombucha with hydrometer readings. We’ll explain below.
Can you take gravity readings on your kombucha brew?
Yes, you can take specific gravity readings to gauge sugar content. But the gravity readings (Original Gravity & Final Gravity) cannot be used to calculate ABV as with other ferments like beer, wine, cider, mead, etc.
Why can’t you use a hydrometer to determine the alcohol content of kombucha?
Kombucha is much more complex than other fermented beverages. Beer, wine, ciders, and other traditional hard beverages are mainly fermented using yeast only. Meanwhile, the Kombucha SCOBY, the culture used to ferment kombucha, contains both yeast and bacteria. What is a SCOBY? The bacteria in the kombucha culture make the primary fermentation a two-step fermentation rather than one-step yeast-only fermentation.