Kombucha Sugar Calculator
Calculate the right amount of sugar and tea for your kombucha brew based on batch size and desired sweetness.
Kombucha brewing requires a specific ratio of sugar, tea, and starter liquid (from a previous batch) to properly feed the SCOBY (Symbiotic Culture of Bacteria and Yeast) and produce a healthy, flavorful fermented tea. Getting the sugar ratio right is critical — too little starves the SCOBY, too much creates an overly sweet or alcoholic brew.
Standard Kombucha Ratio (per 1 gallon / 3.8 liters):
- Sugar: 1 cup (200 g / 7 oz)
- Tea: 4–6 tea bags or 4–6 teaspoons loose leaf
- Starter liquid: 1–2 cups (240–480 mL)
- Water: remainder of volume
Sugar Concentration: The standard ratio produces approximately 5–7% sugar concentration by weight. During primary fermentation (7–14 days), the SCOBY consumes 60–80% of the sugar, leaving the finished kombucha with approximately 1–3% residual sugar.
Sugar concentration = (Sugar weight / Total liquid weight) × 100
Residual sugar ≈ Initial sugar × (1 - fermentation efficiency)
Sugar Type Selection:
| Sugar Type | Suitability | Notes |
|---|---|---|
| White cane sugar | Best | Clean fermentation, SCOBY favorite |
| Organic cane sugar | Excellent | Slightly more minerals |
| Raw/turbinado sugar | Good | Adds slight molasses flavor |
| Brown sugar | Acceptable | Stronger flavor, monitor SCOBY |
| Honey | Use cautiously | Different microbes, use less (3/4 cup) |
| Maple syrup | Experimental | Unpredictable results |
| Artificial sweeteners | Never | Cannot feed the SCOBY |
Tea Selection: Black tea and green tea are the most reliable bases. The SCOBY needs the tannins, nitrogen, and caffeine from real tea (Camellia sinensis) to thrive.
| Tea Type | Caffeine | Flavor Profile |
|---|---|---|
| Black tea | Highest | Bold, robust, traditional |
| Green tea | Moderate | Light, floral, delicate |
| Oolong tea | Moderate | Complex, between black and green |
| White tea | Low | Very mild, subtle |
| Herbal tea (alone) | None | Not recommended as sole base |
Fermentation Timeline:
- Day 1–3: Sugar consumption begins, slight fizz
- Day 4–7: Active fermentation, increasing tartness
- Day 7–10: Sweet-tart balance (most people bottle here)
- Day 10–14: More tart/vinegary, lower sugar
- Day 14+: Very tart, approaching vinegar territory
Temperature Matters: Ideal fermentation temperature is 75–85°F (24–29°C). Below 70°F (21°C), fermentation slows dramatically. Above 90°F (32°C), harmful bacteria may outcompete beneficial ones. Use a thermometer strip on your brewing vessel to monitor temperature.
Second Fermentation (Carbonation): After primary fermentation, bottle with 1–2 teaspoons of sugar or fruit juice per 16 oz (500 mL) bottle. Seal tightly and leave at room temperature for 2–4 days. This creates natural carbonation. Burp bottles daily to prevent excessive pressure buildup. Refrigerate to stop fermentation and enjoy cold.
Safety Notes: Always use clean equipment. The brew should smell pleasantly tart, never like mold or cheese. If you see fuzzy mold (not the smooth, rubbery SCOBY growth), discard the entire batch and SCOBY. A healthy SCOBY is smooth, tan/white, and may have brown yeast strands underneath.
Scaling Rule: All ingredients scale linearly with batch size. A 2-gallon batch uses exactly twice the sugar, tea, and starter of a 1-gallon batch.