Water Kefir Soda

Why this method

Water kefir (tibicos) is a self-propagating community of bacteria and yeast bound in translucent, jelly-like grains. Drop the grains into sugar water and they ferment it fast — yeasts make ethanol and CO₂, lactic- and acetic-acid bacteria make acid — yielding a tart, lightly fizzy, lightly probiotic soda in 24-72 hours. Unlike kombucha, there is no surface SCOBY and no long acid build; the grains do the work and are strained out and reused indefinitely. Carbonation is finished in a separate sealed second ferment, which is where pressure (and the need to burp) comes in.

Parameters

Parameter	Value
Grains	~3-4 tbsp (about 50-80 g) per liter
Sugar	50-80 g per liter (1:20 sugar:water is a reliable start)
Water	non-chlorinated; grains like minerals (unrefined sugar helps)
Primary (F1) temperature	21-27°C / 70-80°F (about 25°C is ideal for fizz)
Primary duration	24-72 hours (1-2 days typical)
Second ferment (F2, sealed)	21-27°C, 12-48 hours
Cold storage / arrest	2-4°C

Equipment

• Glass jar, breathable cloth and band for F1 (never reactive metal — it harms the grains)
• Plastic or wood strainer (avoid prolonged metal contact)
• Pressure-rated swing-top bottles for F2
• Non-chlorinated water; chlorine and chloramine stress the grains

Method

Feed the grains

Dissolve 50-80 g sugar in 1 L non-chlorinated water, cool to room temperature, and add the grains. A pinch of unrefined sugar or a small piece of dried fig adds the minerals tibicos prefer.

Primary ferment (F1)

Cover with cloth and hold 21-27°C for 24-72 hours. It is done when the liquid tastes less sweet and faintly tart and shows fine bubbles. Going too long starves and stresses the grains.

Strain and reserve

Strain out the grains with a plastic or wood strainer. Start a fresh batch with the grains immediately, or rest them in fresh sugar water in the fridge.

Second ferment for carbonation (F2)

Bottle the strained liquid into pressure-rated bottles with a little fruit or juice (leave ~2-3 cm / about an inch of headspace). Seal and hold at room temperature 12-48 hours. The residual yeast ferments the added sugar in the closed bottle, trapping CO₂.

Burp, then chill

Once bottles feel firm, refrigerate at 2-4°C to slow the ferment and lock in the fizz. Chill before opening — cold liquid holds CO₂ and gushes less.

Caution

Sealed second ferments build real pressure and can over-pressurize or burst, especially in warm rooms or with sugary fruit. Use pressure-rated bottles only, leave headspace, and burp daily — briefly crack the lid to release gas. If a bottle feels rock-hard, open it slowly over a sink with a towel over the cap. Refrigerate to arrest once carbonated.

Note

Water kefir is mildly acidic, not a high-acid preserved product — treat it as a fresh beverage, keep it refrigerated, and drink it within a week or two. Like all sugar ferments it carries a small amount of alcohol (usually below ~1% ABV); longer, warmer, sealed ferments produce more.

Tip

Cloudy water, healthy grain growth, and a clean yeasty-tart smell are normal. A surface scum on a sealed F2 is unusual; off, rotten, or moldy smells mean discard the batch and rinse the grains.

💧 Sugar in fermentation

💧 Water and minerals

See also

• Kombucha and Jun — the other carbonated culture drinks
• Sugar in fermentation — what feeds the grains
• Water and minerals — why chlorine-free, mineral-bearing water matters
• Time and temperature — tuning fermentation speed