11. There shall be charged, collected, levied, and paid for the use of Her Majesty in respect of beer brewed in the United Kingdom, a duty calculated according to the specific gravity of the worts thereof; that is to say,
Upon every thirty-six gallons of worts of a specific gravity of one thousand and fifty-seven degrees the duty of six shillings and threepence;
and so in proportion for any difference in quantity or gravity.
