Water Kefir Batch Calculator
Calculate sugar, mineral, and water ratios for water kefir fermentation based on grain quantity and batch size.
What is water kefir?
Water kefir (also called tibicos) is a fermented probiotic beverage made by culturing sugar water with water kefir grains — translucent, gelatinous colonies of bacteria and yeast. Unlike milk kefir grains, water kefir grains feed on sucrose and produce a mildly sweet, slightly fizzy drink in 24–48 hours.
Base ratio formula:
The standard ratio for water kefir is:
Sugar = Batch volume (ml) × 0.04 to 0.08 (4–8% sugar by volume)
Grains = Batch volume (ml) × 0.03 to 0.06 (3–6 tablespoons per liter)
Mineral source = 1/8 tsp per liter (or one dried fig, or a pinch of sea salt)
Recommended ratios by ferment style:
| Style | Sugar % | Grains/Liter | Ferment Time | Result |
|---|---|---|---|---|
| Mild (beginner) | 4% (40 g/L) | 3 tbsp | 24 hours | Slightly sweet, mild fizz |
| Standard | 6% (60 g/L) | 4 tbsp | 24–36 hours | Balanced sweet/tart |
| Strong | 8% (80 g/L) | 5 tbsp | 36–48 hours | Tart, more probiotic |
| Extra fizzy | 6% (60 g/L) | 4 tbsp | 24 hrs + 24 hrs 2F | Very carbonated |
Sugar types and their effects:
| Sugar Type | Grain Health | Flavor | Notes |
|---|---|---|---|
| White cane sugar | Good | Neutral/clean | Most common, reliable |
| Raw/turbinado | Excellent | Mild molasses | Extra minerals feed grains |
| Brown sugar | Good | Rich, caramel | Use for darker kefir |
| Coconut sugar | Moderate | Earthy, complex | Low glycemic but slower ferment |
| Honey (pasteurized) | Fair | Floral | Antibacterial properties slow ferment |
| Maple syrup | Fair | Distinct maple | Expensive, interesting flavor |
Example batch (1 liter, standard style):
- Water: 1000 ml (filtered, non-chlorinated)
- Sugar: 60 g (about 4 tablespoons)
- Grains: 4 tablespoons (~60 g)
- Mineral: 1/8 tsp unrefined sea salt or 1 dried fig
- Ferment: 24–36 hours at 20–25°C (68–77°F)
Second fermentation (2F) for carbonation:
After straining out grains, bottle the liquid with a splash of fruit juice (10–20% of volume) in a swing-top bottle. Seal and leave at room temperature 12–24 hours. The residual bacteria consume the fruit sugars and produce CO2. Burp bottles daily to prevent over-pressurization.
Temperature and fermentation speed:
Every 5°C increase roughly doubles fermentation speed. At 30°C, a batch finishes in 12–18 hours. Below 18°C, fermentation stalls. Ideal range is 20–25°C.
Grain health:
Healthy grains grow 5–10% per batch. If grains shrink, they need more minerals — add a pinch of baking soda, a drop of molasses, or a dried fig. Avoid metal utensils and chlorinated water, which damage the grain colony.