Kombucha Recipe Calculator

Frequently Asked Questions

What are the standard kombucha ratios?

A typical 1-gallon batch uses about 1 cup (≈ 200 g) of sugar, 8 tea bags (or 2 tbsp loose tea), a SCOBY, and 1–2 cups of mature starter tea. The starter's acidity protects the brew from contamination.

How much starter tea should I add?

Use roughly 10–20% of the batch volume as starter tea - about 1.5–2 cups per gallon. This drops the starting pH below ~4.5 to keep harmful microbes from establishing.

How does sugar scale with batch size?

Keep the ~1 cup sugar per gallon ratio: a 2.5-gallon batch needs about 2.5 cups (≈ 500 g) of sugar and 20 tea bags. Most sugar is consumed during fermentation, leaving a tart, lightly sweet brew.

Why is the SCOBY and pH important?

The SCOBY (symbiotic culture of bacteria and yeast) ferments sugar into acids and a trace of alcohol (usually under 0.5%). Maintaining low pH and clean equipment is the main safeguard against mold or spoilage.

Provided by AllCalculators.io
Free online calculators for everyday. No registration required.

Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

JavaScript is required to use the interactive calculator above. The questions and answers below remain readable without JavaScript.

How This Calculator Works

Enter your batch size and, if you like, adjust the sugar and starter-tea amounts per gallon. The calculator scales sweet-tea ingredients for a healthy kombucha ferment: sugar, starter (mature) tea, sweet tea water, and an approximate tea-bag count. It is built for home fermenters scaling a recipe up or down.

This is an informational fermentation tool, not medical or drinking advice. Kombucha contains trace alcohol from fermentation; ferment in clean conditions, know your limits, and enjoy responsibly.

Formula / Method

The standard ratios are about 1 cup of sugar and 1–2 cups of mature starter tea per gallon of finished kombucha, with the rest made up of brewed, sweetened tea. One cup of granulated sugar weighs roughly 200 g, and a gallon is 16 cups, so sugar grams = cups × 200 and sweet-tea water = 16 × gallons − starter cups. Starter tea (and its acidity) protects the batch by lowering pH quickly, which is why the 10–20% starter share matters as much as the sugar.

Worked Example

For a 1-gallon batch at 1 cup sugar and 1.5 cups starter: sugar = 1 cup ≈ 200 g, starter = 1.5 cups (≈ 0.35 L), and sweet-tea water = 16 − 1.5 = 14.5 cups. Steep enough tea for that water - roughly one bag per two cups, so about 7–8 bags - dissolve the sugar while hot, cool to room temperature, then add the starter and SCOBY. A wide jar where the SCOBY can spread across most of the surface ferments more reliably than a tall, narrow one.

Common Mistakes

Skimping on starter tea - too little acidity invites mold; keep at least one cup per gallon.

Adding the SCOBY to hot tea, which can kill the culture; always cool to room temperature first.

Using a narrow vessel - surface area drives the ferment, so favor a wide-mouth jar.

Sealing the jar; first-ferment kombucha needs breathable cloth cover, not an airtight lid.

Cutting sugar to "make it healthier" - the yeast eats most of it, and starving the culture stalls fermentation.

Tips & FAQ

How long should I ferment? Typically 7–14 days; taste from day 7 - longer means less sweet and more tart. Why does brew time change sweetness? Yeast convert sugar to acids over time, so a shorter ferment is sweeter and a longer one is sour. Does temperature matter? Yes - 75–85°F (24–29°C) is ideal; cooler slows everything down. Is there alcohol? A small amount (usually well under 0.5% in first ferment); a long or bottle-conditioned second ferment can raise it. Treat ratios as a starting point and adjust to your taste and climate.

Kombucha Recipe Calculator

Frequently Asked Questions

Related Beverage & Brewing Calculators