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HMRC internal manual

Cider Guidance

Cider production: cask conditioned cider: strength

The strength of cask cider can rise after it has been packaged.

Cask cider is racked into cask when fermentation is judged to be sufficiently complete. Secondary fermentation in cask may cause the actual abv to increase.

Duty is charged on the finished cider and the cider maker must account for duty on the strength at which the cider is expected to be when it is consumed. The cider maker can establish the strength that the cider will have attained at the optimum time for consumption by monitoring the strength in his sample cellar.