Kombucha Priming Sugar Calculator

For a standard 16 oz (473 ml) bottle at medium carbonation (~2.5 vols CO₂), you need approximately 2.5–3.5 grams of white sugar (about ⅔ teaspoon) per bottle. This can vary based on your brew temperature and sugar type. Use the calculator above with your specific parameters for a precise measurement. For honey, you'd need about 3–4.5 grams per bottle due to its lower fermentable sugar content.

Absolutely! Different sugars have varying fermentable sugar content:
• White sugar (sucrose): ~100% fermentable – the baseline
• Brown sugar: ~95% fermentable – adds subtle molasses notes
• Honey: ~80% fermentable – contains water and complex sugars
• Maple syrup: ~65% fermentable – adds rich flavor but needs more volume
• Fruit juice: Varies widely (5–15% sugar content) – adds both sugar and flavor
Our calculator automatically adjusts the amount based on your chosen sugar type using efficiency coefficients.

Temperature plays a crucial role in carbonation. Warmer kombucha at bottling time retains less dissolved CO₂ from the primary fermentation. At 20°C (68°F), residual CO₂ is about 1.0 volumes; at 26°C (79°F), it drops to ~0.75 volumes. This means warmer brew needs slightly more priming sugar to reach the same final carbonation level. Our calculator accounts for this by estimating residual CO₂ based on your input temperature and adjusting the sugar recommendation accordingly.

Bottle explosions are dangerous and preventable:
1. Use proper bottles: Only use fermentation-grade flip-top bottles or heavy beer bottles rated for pressure. Never use square bottles or thin glass.
2. Don't over-prime: Stay below 3.5 vols CO₂ for most home setups. Our calculator warns when you're in the danger zone.
3. Monitor F2: Check carbonation after day 2. Refrigerate bottles once desired fizz is reached – cold halts fermentation.
4. Burp bottles: For high-carbonation brews, briefly open one test bottle daily to release excess pressure.
5. Leave headspace: Fill bottles to about 1–1.5 inches from the top.

"Volumes of CO₂" measures how much carbon dioxide is dissolved in the liquid. 1 volume means the liquid contains its own volume in dissolved CO₂ gas (at standard pressure). Here's what different levels feel like:
• 1.5–2.0 vols (Light): Gentle sparkle, soft mouthfeel – like a lightly sparkling water
• 2.0–2.7 vols (Medium): Classic kombucha fizz – pleasant and refreshing, similar to most commercial kombuchas
• 2.7–3.3 vols (High): Bold carbonation – like soda or champagne
• 3.3–4.0 vols (Extra High): Intense fizz – approaching beer/soda levels, requires sturdy bottles

Several factors can cause flat kombucha:
• Insufficient sugar: The most common culprit. Use this calculator to ensure you're adding enough.
• Cold temperature: F2 below 18°C (64°F) slows yeast activity dramatically. Aim for 22–26°C (72–79°F).
• Not enough yeast: If you filtered out too much sediment, you may have removed active yeast. Include some F1 sediment in your bottles.
• Bottle seal issues: Check that flip-top gaskets are intact and sealing properly.
• Too short F2: Give it at least 2–5 days. Cooler temps require longer.

Yes! When you add fruit, puree, or flavored syrups, they contribute additional fermentable sugars. If you're adding fruit in addition to priming sugar, reduce your priming sugar by roughly 30–50% to avoid over-carbonation. For fruit-only F2 (no added sugar), most fruits at 15–20% of bottle volume provide enough sugar for medium carbonation. Our "Fruit Juice" sugar option gives an estimate, but fruit sugar content varies – berries, pineapple, and mango are higher in sugar than citrus or cucumber.