Kombucha is the gateway ferment for a lot of home brewers, it's fast, requires no heat, produces a genuinely complex drink, and the feedback loop is short enough to learn quickly. I've been brewing kombucha alongside beer for years, and the discipline is surprisingly similar: you're managing a microbial culture, monitoring pH, and building flavor through timing and temperature control. The biggest mistake beginners make is treating the SCOBY as magic instead of understanding what it actually does.
What you need to get started
| Item | Quantity | Notes |
|---|---|---|
| SCOBY + starter liquid | 1 SCOBY + 1–2 cups | Starter must be raw, unflavored kombucha at pH 2.5–3.5 |
| Black or green tea | 4–6 teabags (or 2 tbsp loose) | Avoid flavored teas or anything with oils |
| White sugar | 1 cup (200g) | Per gallon; cane sugar preferred over honey or alternatives |
| Filtered water | 1 gallon | Avoid chloramine, use filtered or let tap sit 24h |
| Wide-mouth glass jar | 1 gallon capacity | Cloth cover, not airtight lid, needs airflow during F1 |
| pH strips or meter | , | Range 2–6; strips accurate enough for kombucha |
First fermentation (F1) process
- Brew strong tea: steep 4–6 teabags in 4 cups of boiling water for 5–7 minutes. Remove bags.
- Dissolve 1 cup sugar into hot tea. Stir until fully dissolved.
- Add cold filtered water to reach 1 gallon total. Temperature must be below 90°F/32°C before adding SCOBY, heat kills the culture.
- Pour sweet tea into a clean glass jar. Add starter liquid (1–2 cups of unflavored raw kombucha). Add SCOBY.
- Cover with a breathable cloth secured with a rubber band. No lid, the culture needs oxygen exchange.
- Ferment at 72–78°F/22–26°C for 7–14 days, out of direct sunlight. Cooler temperatures slow fermentation; below 65°F/18°C the culture goes dormant.
- Taste starting at day 7. Target pH: 2.5–3.5. The flavor should be tart but not vinegary, with some residual sweetness. Remove SCOBY when it reaches your preferred tartness.
Second fermentation (F2): adding carbonation and flavor
F2 is what transforms flat kombucha into sparkling kombucha with fruit or botanical character. After removing the SCOBY and reserving 1–2 cups of starter for the next batch, bottle the kombucha in swing-top bottles or plastic bottles (use plastic as a pressure gauge, when the bottle firms up noticeably, it's carbonated). Add flavoring per 16 oz bottle: 1–2 tablespoons of fruit juice or puree, fresh ginger slices, or a few berries. Seal and leave at room temperature for 1–3 days, then refrigerate. The residual yeast ferments the fruit sugar to produce CO₂ in the sealed bottle. Burp bottles once daily to prevent over-pressurization.
The best F2 flavors I've found: fresh ginger + lemon, blueberry, or mango with jalapeño for heat. The key is adding enough fermentable sugar to produce carbonation without so much that you get bottle bombs. Keep F2 fermentation under 3 days at room temperature; move to the refrigerator immediately when carbonated.
SCOBY care and ongoing batches
Your SCOBY grows a new layer with every batch. After 3–4 batches you'll have a thick "hotel" of SCOBY layers. Peel off and compost the oldest bottom layers; keep 1–2 healthy layers for brewing. Store extra SCOBY in starter liquid in the refrigerator if you need to pause brewing, it can survive months refrigerated, but needs a slow reactivation batch (smaller, room temperature for 2 weeks) before returning to full production. The Kombucha Brewers International maintains brewing standards and troubleshooting resources for continuous-brew systems and commercial-scale operations.
Common Questions
My kombucha tastes like vinegar. Did I ruin it?
Not ruined, it's over-fermented. Kombucha that's been in F1 too long at warm temperatures becomes very acidic (pH below 2.5) with a harsh, vinegary flavor. It's technically safe but unpleasant to drink. Use it as starter liquid for the next batch (it's extremely potent starter) or as a cleaning rinse or salad dressing. To prevent this: taste starting at day 7, keep fermentation temperature below 78°F/26°C, and err toward bottling earlier rather than later, F2 adds more flavor development time.
Can I use honey instead of white sugar?
Honey works but has trade-offs: raw honey contains antimicrobial compounds (hydrogen peroxide, phytochemicals) that can stress the SCOBY culture, especially in the first few batches. If using honey, use pasteurized honey rather than raw, reduce quantity by 25% (honey is sweeter by weight), and expect slower fermentation. Experienced brewers who know their culture handles honey well can use it successfully, but white cane sugar is the standard for a reason, and it's what the culture evolved to process most efficiently.
Why is my SCOBY floating sideways or sinking?
SCOBY position doesn't affect fermentation quality, it's not an indicator of health. SCOBYs float, sink, grow sideways, or form strange shapes based on CO₂ bubble attachment, temperature gradients in the vessel, and the particular culture's morphology. A sinking or sideways SCOBY ferments identically to a floating one. The liquid ferments because of the full culture (SCOBY plus the yeast and bacteria dispersed throughout the liquid), not just the cellulose mat. As long as the kombucha is tasting right and the pH is dropping, ignore the SCOBY's position.