Free Mash-Tun Act (1880). More accurately known as the “Inland Revenue Act, 1880 [43 & 44 Vict. Ch.20],” this Act changed the emphasis of brewery taxation in Britain from malt to beer. The changes British Prime Minister (and Chancellor of the Exchequer) William Gladstone made were to influence the behavior of British brewers for over 100 years. Instead of a tax on malted barley (instigated in 1660), the brewer was now allowed far more leeway in choosing his raw materials. (A tax on hops had been removed 18 years earlier.) In his budget speech of June 10, 1880, Gladstone stated the aims of the Act to be:
To give the brewer the right to brew from what he pleases, and he will have a perfect choice both of his materials and his methods. I am of the opinion that it is of enormous advantage to the community to liberate an industry as large as this with regard to the choice of those materials. Our intention is to admit all materials whatever to perfectly free and open competition.
Malt substitutes would henceforth become commonplace, and essential, in years of poor barley harvest. The point of duty now revolved around the volume and strength of wort produced during a brew, and, as a result of experimentation, it was deemed that two bushels of malt should make 36 gallons (one barrel) of wort at an original gravity (OG) of 1057° (approximately 14.9°Plato).
The Act also specified that a brewer had to purchase an annual “license to brew” (£1 for common brewers) and must register his premises and each item of brewing equipment (called “the entry”). Notice of 24 hours was required before a brew could commence, and, after carrying out the “normal brewing procedure,” as evident from the entry, the worts had to be collected in a gauged vessel within 12 hours of mashing. Possession of a saccharometer (used to measure sugar levels;
The OG of the “standard barrel” was reduced to 1055° in 1889 because many smaller brewers had difficulty getting a barrel of 1057° wort from two bushels of malt. With minor tinkering, the 1880 acts held sway until June 1993, when duty became levied on the alcoholic strength of the finished beer (ABV).