Abbreviation: OG
Summary: In HMRC's Alcohol Duty glossary, original gravity is the specific gravity of wort before fermentation.
Reference: Alcoholic products technical guide (opens in a new tab)
HM Revenue and Customs · Reference checked 21 July 2026
Where to look: Section 30, Original gravity
The summary above is a concise paraphrase of the cited material. It is not a quotation or a complete statement of law.
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