Short answer: yes, but usually with some black tea
Rooibos can be used to make kombucha, but pure rooibos is a harder base than black tea. Many brewers blend a little black tea into the rooibos, or grow the SCOBY on black tea first and then move it to a rooibos batch. The result is usually sweet, mellow and fruity. Pure rooibos is caffeine-free, but a blend with black tea will contain some caffeine.
What rooibos is
Rooibos (also called red bush) is an herbal infusion made from the needle-like leaves and stems of a South African shrub, Aspalathus linearis. It is not a true tea, because it does not come from the Camellia sinensis plant. Rooibos is naturally caffeine-free, which is why many people choose it.
Why it is not a standard base
Most kombucha guides use true tea because the culture is usually built and tested on it. Rooibos has fewer of the compounds that brewers call tannins, and the SCOBY may ferment more slowly or less predictably on it. This is not a reason to avoid rooibos entirely, but it does mean that it is a more advanced choice.
How to brew a rooibos kombucha
A common approach is to use a blend and keep the rooibos share modest:
- Start with a black tea SCOBY and starter. If you have a healthy culture from a black tea batch, you have the best chance of success.
- Brew a sweet base. Use plain rooibos, or a blend of rooibos with a small amount of plain black tea, and steep it until it is strong. Dissolve about ¾ to 1 cup of plain cane sugar per gallon in the hot tea, as in the basic kombucha method.
- Cool it. Let the tea cool to around room temperature before you add the starter and the SCOBY.
- Ferment. Keep the jar at about 68 to 78°F (20 to 26°C), out of direct sunlight. Start tasting around day 5, and expect the timing to vary.
- Check carefully. Look for fuzzy mold, which means you should discard the batch. Brown or stringy strands are normal yeast.
Rooibos can make a lighter, sweeter batch than black tea, so taste it before you bottle it. A small test batch is a good idea the first time.
Is there a downside to rooibos tea?
For most people, rooibos has few known downsides as a drink. The downsides for kombucha are mostly practical:
- Less predictable fermentation. Because it has fewer of the compounds that brewers rely on, a pure rooibos batch may take longer or ferment less evenly.
- Less research. Rooibos has been studied less than black or green tea, and claims about its health effects are not well established.
- Flavor. Rooibos can taste sweet and round, which some people enjoy. It can also overpower delicate fruit additions.
- Allergy. Allergic reactions to rooibos are possible but uncommon. If you have a known plant allergy, check with a clinician before trying it.
How and when to drink rooibos kombucha
Rooibos kombucha is drunk in the same way as other kombucha: as a small glass, with food, or as a mixer. There is no proven best time of day. For the trade-offs of morning and evening drinking, see should you drink kombucha at night or in the morning.
Because rooibos is caffeine-free, it may suit people who want to avoid caffeine. Kombucha made with a blend may still contain some caffeine from the black tea, so check your blend if caffeine is a concern.
Other bases: does oolong make good kombucha?
Yes. Oolong is a true tea that many brewers use, and it gives a complex, floral result. It is often a good next step after black tea. For details, see oolong kombucha. Other herbal infusions, such as hemp tea, are not standard bases.
Bottom line
Rooibos makes a sweet, caffeine-free kombucha, but it is best treated as a blend or an advanced base rather than a first batch. Start with black tea, then try rooibos once you know your process. For a full list of options, see the best tea for kombucha.