Spirit Blending Calculator

Blend → ABV uses simple weighted average of alcohol volumes. Since you are mixing two spirits (both containing ethanol), volume contraction is minimal compared to spirit + water blending:

Target ABV → Volumes uses the Pearson's Square method — a classic blending calculation used in commercial distilleries. Given two spirit strengths and a target, it finds the proportion of each needed:

If you provide a total volume, the calculator converts this ratio into exact volumes. If not, it gives you the ratio so you can scale to any batch size.

Blending batches from the same still — Two runs may come out at slightly different ABVs. Blend them to create a consistent spirit before diluting to bottling strength.

New make + aged spirit — A high-ABV new make blended with a lower-ABV aged spirit to hit a target strength while preserving barrel flavour.

Neutral spirit + flavoured base — Blending a neutral high-ABV spirit with a lower-ABV fruit or botanical distillate to reach a final bottling ABV.

Adding water (ABV = 0%) — For pure water addition, use our ABV Dilution Calculator which applies OIML density correction for precise results.

Blending is used in two situations: hitting a target bottling ABV, and combining batches or spirit cuts to balance character. The calculator handles both. For ABV targeting, you are almost always adding water to a higher-strength spirit to bring it down to a standard bottling strength such as 40% or 46%. For batch blending, you might be combining hearts from two runs at slightly different ABVs to produce a consistent bottling.

The Pearson Square method used here assumes that volume is additive, which is accurate enough for practical blending. In reality, mixing ethanol and water causes a small volume contraction due to hydrogen bonding. At 40% ABV the actual contraction is approximately 3% of total volume. For home distilling purposes this is negligible, but if you need OIML-precise dilution calculations, use the ABV Dilution Calculator which applies the full density correction.

If you are running multiple batches of the same recipe, the hearts from each run will come off at slightly different ABVs depending on charge volume, still temperature and cut points. Blending these into a single tank before bottling produces a more consistent product than bottling each run separately.

The procedure is straightforward: measure the volume and ABV of each batch, enter them into the blending calculator, and the output tells you the final ABV of the combined volume. From there, use the ABV Dilution Calculator to work out how much water to add to reach your target bottling strength. This two-step process handles any combination of batch volumes and strengths.

Consistency also benefits from resting. After blending, allow the combined spirit to sit for at least 48 hours before final measurement and bottling. The ABV reading immediately after mixing can be slightly off as the ethanol and water have not fully integrated. This is especially noticeable with high-proof blends above 60% ABV.

Some distillers add a small proportion of tails back into hearts before bottling to increase body and congener complexity. This is common in pot still whisky production. The blending calculator works for this use case too: enter your hearts volume and ABV as Spirit A, and your tails volume and ABV as Spirit B. The result shows you the combined ABV of the blend.

The practical limit for tails addition is usually 5 to 10 percent of total volume. Above this the fusel character becomes detectable. Start at 3 to 5 percent, taste the blend, and adjust on the next batch. Heads are rarely added back due to their aldehyde content, but small additions of late heads can contribute fruity notes to some spirit styles such as brandy and agricole rum.