Continuous brew kombucha is made in one large vessel with a spigot: the brewer draws off finished kombucha and immediately replaces it with the same amount of fresh sweet tea, so the culture never has to restart.
Batch brewing starts each ferment from scratch with new sweet tea, starter and culture, which takes more handling but gives a clean break between batches.
Continuous brewing keeps one vessel of kombucha going indefinitely. Instead of starting a new jar each time, the brewer draws finished kombucha from a spigot near the bottom of a large vessel and tops it up with the same amount of fresh sweet tea. Mature kombucha and the culture stay in place, so the new tea turns into kombucha quickly. Batch brewing, the other method, starts each ferment fresh.
| Batch brew | Continuous brew | |
|---|---|---|
| Vessel | A jar or tank, emptied each time | A large vessel with a spigot, never emptied |
| Each cycle | New sweet tea, starter and culture | Draw off, top up the same volume |
| How much is replaced | All of it | No more than 25 to 35 percent at once |
| Time between draws | About 7 to 14 days per batch | About 5 to 7 days after a 2 to 4 week first brew |
| Handling the culture | Every batch | Rarely; a full clean every 6 to 12 months |
How continuous brew works
Kombucha Kamp, the teaching business of Hannah Crum and Alex LaGory, authors of The Big Book of Kombucha, is the best-known advocate of the method. Its guide starts the vessel about a quarter full of mature kombucha, adds the culture, and fills the rest with sweet tea. The first brew takes two to four weeks. After that the brewer draws a gallon and replaces a gallon, and later draws are ready in five to seven days. The vessel should be glass, porcelain, oak or food-grade stainless steel, with a spigot that will not react with acid.
The case they make for it is mostly practical: less handling, steadier flavor and fizz from one draw to the next, and a constant supply. The low pH of a mature vessel also makes it harder for anything unwanted to move in. They recommend checking pH monthly and looking over the culture every few months.
Why many brewers still batch
Batch brewing gives each ferment a clean start and a clean end, which makes it easy to change the tea, test a new sugar or throw away a batch that went wrong without touching the next. That control is why commercial producers, who need to document each batch, mostly work in batches, as the steps in the Code of Practice assume. At home and in small taprooms, continuous brew is popular for exactly the opposite reason: it asks very little of the brewer once it is running.
What it means in the glass
A continuous brew drawn at the same interval tastes much the same week to week, slightly sharper than a short batch because the vessel always holds mature kombucha. A batch brewer can push a single batch shorter for more sweetness, or longer for more bite. Either way the second fermentation, with its fruit and seal, still comes afterwards.
Questions
What is continuous brew kombucha?
A method where kombucha is drawn from a spigot near the bottom of a large vessel and topped up with fresh sweet tea, so it is always brewing.
How much can you draw off at once?
Kombucha Kamp suggests replacing no more than 25 to 35 percent of the total volume at a time.
How often can you draw from a continuous brew?
After a first brew of about two to four weeks, Kombucha Kamp says about every five to seven days.
Is continuous brew better than batch brew?
Neither is better in itself. Continuous brew is less handling and more steady; batch brewing makes each batch separate and easier to adjust.
