Dilution Reference

Diluting 75% ABV to 40% ABV

How much water to add to bring 75% spirit down to 40% ABV — with worked examples and the formula.

Water to Add: 75% → 40% ABV

Standard volume method. Verify the final strength with a hydrometer before bottling.

Per 1 Litre
875mL water
Per 750 mL bottle
656mL water
Per 1 US gallon
3312mL water
Final volume / litre
1875mL
water to add = volume × (current ABV − target ABV) ÷ target ABV
= 1000 × (75 − 40) ÷ 40 = 875 mL per litre
Open the interactive ABV Dilution Calculator →

About this dilution

75% is near the practical ceiling for many home column stills, while 40% is the legal minimum and standard bottling strength for most spirits. Bringing 75% down to 40% means adding roughly 875 mL of water for every litre of spirit, increasing the batch to about 1875 mL.

For casual reduction the standard volume method above is accurate enough. When bottling at an exact legal strength, switch to OIML Precise mode in the calculator, which corrects for the slight volume contraction that occurs when ethanol and water mix.

Verify before bottling: a calibrated alcoholmeter is the only way to confirm you have hit 40% ABV. Measure at 20°C.

View on Amazon → As an Amazon Associate we earn from qualifying purchases.

Common questions

How much water do I add to dilute 75% ABV to 40%?

Add roughly 875 mL of water to each litre of 75% spirit to reach 40% ABV. The formula is water to add = volume times (current ABV minus target ABV) divided by target ABV.

Why should I verify the result with a hydrometer?

Ethanol and water contract slightly when mixed, so the real strength can sit just under the calculated figure. Always confirm with a calibrated alcoholmeter at 20°C before bottling.
Knowledge Base

Distilling Guides & Reference Articles

In-depth guides written for home distillers and craft producers — from reading a hydrometer to making clean spirit cuts.

Technique
Measurement
Fermentation
Craft & Aging