Kombucha Flavoring Calculator

Plan your second-fermentation flavoring: enter your bottles and what you add to each one, and get the total juice, fruit and sugar to prepare for the whole batch.

Number of bottles

Count every bottle you will fill in this batch, including any smaller taster bottles - the totals scale linearly with the count.

Bottle size

The fill volume of one bottle. Standard swing-top bottles hold 500 ml and larger ones 750 ml; use the volume you actually fill, not the nominal size filled to the brim.

Juice per bottle (% of volume)

10-15% juice is the classic ratio for flavor and carbonation - about 60-75 ml in a 500 ml bottle. Strongly flavored juices such as ginger or berry work well at the low end.

Fruit pieces per bottle

Fresh or frozen fruit weighed per bottle, about 20-40 g for 500 ml. Fruit adds flavor and fermentable sugar at the same time, so lower the sugar below when using it.

Sugar per bottle

Granulated sugar per bottle. Sugar here feeds carbonation, so 5-10 g per 500 ml bottle is plenty - skip it entirely when your juice or fruit is already sweet.

Results

Total juice

360ml

Total fruit: 180 g
Total sugar: 48 g
Batch volume: 3 L

Every addition feeds the yeast: stacking sugar on top of sweet juice or fruit can build enough pressure to burst bottles. Stay near the classic ratios, use pressure-rated bottles and chill before opening.

How the flavoring math works

Each addition is planned per bottle and multiplied by the bottle count: juice is a percentage of the bottle volume (bottles x ml x pct / 100), while fruit and sugar are weighed per bottle. The batch volume is simply bottles x bottle size, so a six-pack of 500 ml bottles is 3 liters to flavor.

juice (ml) = bottles x bottle (ml) x pct / 100; fruit (g) = bottles x fruit per bottle; sugar (g) = bottles x sugar per bottle

Working out the ferment itself? The kombucha sugar calculator sizes 2F additions by sweetness level, and the second fermentation time calculator tells you how long the bottles need to carbonate.

Frequently asked questions

How much juice should I add per bottle?

10-15% of the bottle volume is the classic range - 50-75 ml in a 500 ml bottle. That is enough sugar and flavor for solid carbonation in 3-7 days. Very sweet juices can go lower, and tart ones such as cranberry can go a little higher.

Can I use fruit pieces instead of juice?

Yes. About 20-40 g of diced fresh or frozen fruit per 500 ml bottle works well, and frozen fruit breaks down and releases more flavor. Fruit brings its own sugar, so cut the added sugar to 0-5 g per bottle to avoid over-carbonation.

How do I avoid bottle bombs?

Do not stack sweet additions - pick juice, fruit or sugar rather than maximum amounts of all three, keep total added sugar near 5-10 g per 500 ml bottle, and refrigerate as soon as the fizz is right. Use pressure-rated bottles and open the first tester over the sink.