get FermentCalc

Kombucha Dilution Calculator

Brewed double-strength or ended up with a too-tart concentrate? Enter the volume and strength you have plus the strength you want, and get exactly how much water to add.

ml

The volume of the strong brew you are starting from - a double-strength batch stored in the fridge, an over-reduced sweet tea, or any brew you want to cut before drinking.

x

How many times stronger than drinking strength the brew is: 2 means double-strength, 3 means triple. Leave it at 1 if the brew is already at normal strength and you only want to lighten it.

x

The strength you want after dilution. 1 is standard drinking strength; a lower value such as 0.5 gives a lighter, more diluted drink. It must be weaker than or equal to the concentrate.

Results

Water to add
500ml
Final volume (ml)
1,000 ml
Final volume (L)
1 L

How the dilution math works

Dilution follows C1V1 = C2V2: the concentrate volume times its strength equals the final volume times the target strength, so final volume = concentrate x strength / target, and the water to add is that final volume minus the concentrate. The same math covers cutting an over-tart batch with fresh sweet tea or topping up a double-strength brew stored in the fridge.

final (ml) = concentrate (ml) x C1 / C2; water (ml) = final - concentrate

Sizing the brew you are cutting? The kombucha batch calculator gives the full 1F recipe ratios, and the sugar intake calculator shows what a diluted glass actually contains.

Frequently asked questions

Why would I brew double-strength kombucha?

Concentrated brew saves fridge space and stretches a batch further: store 2x kombucha and cut it half and half with water or fresh sweet tea right before drinking. It also helps when a batch came out unusually tart and needs softening rather than more fermentation.

Can I dilute with something other than water?

Yes - fresh sweet tea, juice or sparkling water all work and the math is identical. Remember that sweet tea and juice add sugar of their own, which restarts a gentle second fermentation, so chill those drinks and finish them sooner.

Why can the target not be stronger than the concentrate?

Dilution only ever lowers strength: adding liquid cannot remove water or concentrate flavor. To end up with a stronger brew you need to start from something stronger - less water in the next batch, a gentle reduction, or blending in a genuinely concentrated brew.