Kombucha Sugar Ratio Calculator Formula

Understand the math behind the kombucha sugar ratio calculator. Each variable explained with a worked example.

Use the Kombucha Sugar Ratio Calculator

Formulas Used

Sugar Needed

sugar_grams = batch_ml / 1000 * sugar_ratio

Sugar (cups)

sugar_cups = batch_ml / 1000 * sugar_ratio / 200

Tea Bags

tea_bags = ceil(batch_ml / 1000 * tea_bags_per_liter)

Starter Liquid (10%)

starter_ml = batch_ml * 0.10

First Fermentation

ferment_days = 10

Variables

VariableDescriptionDefault
batch_mlBatch Size(mL)3785
sugar_ratioSugar Level70
tea_bags_per_literTea Bags per Liter4
litersDerived value= batch_ml / 1000calculated

How It Works

How to Calculate Kombucha Ingredients

Standard Ratios

Sugar: 50-90 g per liter of water (standard is about 70 g/L or 1 cup per gallon)

Tea: 3-5 tea bags per liter (black or green tea)

Starter: 10% of batch volume (mature kombucha from a previous batch)

Process

1. Brew strong sweet tea and cool to room temperature. 2. Add starter liquid and SCOBY. 3. Cover with a cloth and ferment 7-14 days at 68-85°F. 4. Taste every few days; when the balance of sweet and tart suits you, bottle it.

The SCOBY

The SCOBY (Symbiotic Culture of Bacteria and Yeast) is the living culture that ferments the sweet tea. It consumes the sugar and produces organic acids, CO2, and a small amount of alcohol.

Worked Example

A 1-gallon (3785 mL) batch with standard sugar and 4 bags per liter.

batch_ml = 3785sugar_ratio = 70tea_bags_per_liter = 4
  1. 01Sugar = 3.785 x 70 = 265 g (about 1.3 cups)
  2. 02Tea bags = ceil(3.785 x 4) = 16 bags
  3. 03Starter liquid = 3785 x 0.10 = 379 mL (about 1.5 cups)
  4. 04Ferment for 7-14 days, then bottle for second fermentation.

Frequently Asked Questions

Does the sugar remain in the finished kombucha?

No. The SCOBY consumes most of the sugar during fermentation. A 7-day ferment typically reduces sugar by 60-80%. Longer fermentation produces a more sour, lower-sugar drink. You can test with a refractometer.

What type of tea should I use?

Black tea and green tea work best because they provide the nutrients the SCOBY needs (caffeine and tannins). Avoid herbal teas (which lack these) for primary fermentation. You can blend in herbal teas as a secondary flavoring.

How do I get carbonation?

After first fermentation, bottle the kombucha in swing-top or other pressure-safe bottles and let it sit at room temperature for 2-4 days. The trapped CO2 carbonates the drink. Burp bottles daily to prevent over-pressurization.

Ready to run the numbers?

Open Kombucha Sugar Ratio Calculator