Barrel Ageing Loss Calculator

Work out barrel ageing loss instantly with clear inputs, formula shown and shareable results.

About Barrel Ageing Loss Calculator

Barrel evaporation, the angels' share, compounds geometrically: remaining volume is initial volume times (1 - annual rate) raised to the years. At 3.5% a year, a fifth of the cask is gone after five years and over a third after twelve. Rates depend on warehouse humidity, temperature cycling and cask size.

Formula

Angels' share

Remaining volume = initial volume x (1 - annual loss rate)^years

Worked example

With the default values below, Barrel Ageing Loss Calculator returns Volume Remaining of 167.366. Change any input above and every figure here is recalculated in your browser.

Inputs used

Volume Filledminimum 0 L: 200 L
Annual Evaporation Lossaccepts 0–20 %: 3.5 %
Ageing Periodminimum 0 years: 5 years
Initial Alcohol By Volumeaccepts 0–100 %: 63 %

Results

Volume Remaining: 167.366
Volume Lost To Evaporation: 32.634
Total Loss: 16.317%
Pure Alcohol Remaining: 105.440

Step by step

1Values used
2Angels' share
3Volume Remaining= 167.366
4Volume Lost To Evaporation= 32.634
5Total Loss= 16.317
6Pure Alcohol Remaining= 105.440

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Does alcohol strength rise or fall during ageing?

It depends on humidity. In dry warehouses water evaporates faster and strength rises; in humid conditions alcohol is lost preferentially and strength falls. Scottish warehouses typically see strength fall, Kentucky rickhouses see it rise.

Why do smaller casks lose more?

Surface area to volume ratio is higher, so both evaporation and wood extraction proceed faster. Small casks mature quickly but lose a much larger proportion of their contents.