Page:A Practical Treatise on Brewing (4th ed.).djvu/223

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Saccharometers now in use are graduated to a scale of barrels containing 36 imperial gallons each. If gravities, therefore, be reckoned by barrels containing only 32 gallons, the calculations must be very erroneous. An Irish barrel contains only 32 gallons, and yet many brewers in Ireland, in calculating the gravities obtained from the malt, multiply by their own barrels, and thus persuade themselves that they are getting much greater lengths than the malt could possibly produce. Thus, suppose brewing 30 qrs. of malt, they have 100 Irish barrels in the gyle-tun at 30 lbs. gravity per Long’s instrument (which is equal to 83.4 by Bate’s), they reckon they have 3,000 lbs., or 100 lbs. per qr. Instead of this, however, they have 400 gallons less than 100 barrels, leaving only within a fraction of 89 imperial barrels; they ought, therefore, to multiply 89 by 30, which would make only 2,670, instead of 3,000 lbs. Divide, therefore, 2,670 by 30, which will give the true gravity per qr., or 89 lbs., instead of 100 per Long’s instrument (or 247.4 by Allan’s or Bates’).

Saccharometers which have been long in use will, from the friction used in cleaning them, become lighter, and consequently show considerably higher