Short answer: yes, but usually blended with true tea
Yerba mate can be used to make kombucha. It is an herb from South America rather than a true tea, so it does not come from the Camellia sinensis plant. For that reason, most brewers blend it with black or green tea rather than using it alone. The result is earthy and mild, with a caffeine lift.
What yerba mate is
Yerba mate is made from the leaves of the Ilex paraguariensis plant. It is traditionally brewed and shared as a drink in parts of South America. It contains caffeine, along with related compounds. Mate can be smoked during processing, which gives a harsher, smoky flavor. For kombucha, choose smoke-free mate if you can find it.
Flavor and caffeine
Yerba mate kombucha tends to be milder and less sharp than black tea kombucha. Brewers often describe it as earthy, grassy or faintly apple-like. The flavor depends on the mate, the blend and how long the batch ferments.
Yerba mate contains caffeine, and kombucha made with it will usually contain some too. The amount varies with the mate, how much you use and how strongly you brew. If you are sensitive to caffeine, check why kombucha can make you feel buzzed and start with a small glass.
Why blend it with true tea
A pure mate infusion is not a true tea, and the culture may not get everything it needs over several batches. Brewers who use mate alone often report that the SCOBY changes or weakens over time. Blending mate with black or green tea gives the culture a familiar base. One common approach is to mix roughly half mate and half true tea, then adjust by taste.
A test-batch recipe (per gallon)
This is a starting point for a small test batch, not a fixed formula:
- Choose your tea. Use about half your usual tea amount as plain black or green tea, and about half as smoke-free yerba mate. For a gallon, that might be 3 to 4 bags of each, or about 1 to 2 tablespoons of loose leaf of each.
- Steep. Use water that is hot but not boiling, and steep briefly. Mate can turn bitter with a long or very hot steep, so taste as you go and strain the leaves out when the flavor is right.
- Sweeten. Stir in about ¾ to 1 cup of plain cane sugar while the tea is hot, then add cool filtered water to bring the batch to one gallon.
- Cool. Let the tea cool to around room temperature, about 70 to 80°F (21 to 27°C), before adding the culture.
- Add the culture. Add 1 to 2 cups of unflavored starter tea and the SCOBY. Cover with a breathable cloth and a rubber band.
- Ferment. Keep the jar at about 68 to 78°F (20 to 26°C), out of direct sunlight, for 7 to 10 days. Start tasting around day 5.
- Bottle. Bottle as in how to make kombucha tea. Keep 1 to 2 cups of finished kombucha for your next starter.
Flavor ideas for bottling
Yerba mate pairs well with citrus, ginger and some herbs. Add these at bottling, not during the first fermentation:
- A little lemon or grapefruit juice, for brightness
- Fresh ginger, for warmth
- A small amount of mint, for a fresh finish
Add small amounts, taste, and adjust before sealing the bottles.
Caffeine and who should be careful
Yerba mate contains caffeine, so a yerba mate kombucha is a caffeinated drink. Many health guidelines suggest that pregnant people keep caffeine below about 200 mg a day. If you are pregnant, breastfeeding, sensitive to caffeine, or taking medicine that interacts with it, check with a clinician before drinking it. Children should not drink caffeinated kombucha regularly.
Troubleshooting
- Bitter flavor. Shorten the steep, use cooler water, or blend in more true tea.
- Slow fermentation. Check the temperature, use enough starter tea, and make sure the tea was cool before adding the culture.
- Thin or weak SCOBY. Brew the next batch with more black or green tea and less mate, then move back to a blend.
- Mold. Discard the batch if you see fuzzy spots, which can be blue, black, green or white. Brown or stringy strands are normal yeast.
Homemade kombucha is less predictable than commercial kombucha. Keep your equipment clean, and talk to a clinician before drinking it if you have a health condition or take medicine. For more on health questions, see does kombucha clean the liver?
Bottom line
Yerba mate can make an earthy, caffeinated kombucha, but it is best blended with black or green tea. Run a small test batch first, steep briefly, and use smoke-free mate. For other non-standard bases, see rooibos kombucha and the best tea for kombucha.