A Practical Treatise on Brewing/Saccharometer

2030021A Practical Treatise on Brewing — SaccharometerWilliam Black

SACCHAROMETER.

The late Mr. Richardson, of Hull, was the inventor of an instrument for ascertaining on scientific principles, the real value of malt. Before his time, many rude means had been resorted to for that purpose. Equal quantities, for instance, of wort and water were weighed against each other, but this method was found to be both troublesome and uncertain, and was only practised by very few. Since his time, various instruments have been introduced for the same purpose; but for real utility in practice, it has not as yet been excelled by any; and having only one pound gravity on the stem, fewer mistakes can occur than when there are 10 or 20 lbs. in the same space. These instruments are still manufactured and sold by Mr. Joseph Long, Hydrometer-maker, &c., 20, Little Tower Street, London. For his scientific knowledge, and accuracy in all matters of this kind, we can vouch. The Saccharometer sanctioned by government, is that constructed by Mr. Bates, which shows the specific gravity of the worts, as compared with water at unity, or 1000; thus progressing to 1020, 40, 60, 80, to 1140, which is quite enough for the specific gravity of worts, for beer of every description. Richardson’s instrument shows the increase of weight of the worts according to the actual number of pounds of saccharine matter, held in solution by the said worts. For instance, if 50 lbs. specific gravity by Bates’s or Allan’s instruments were held in solution by the worts, thirty pounds of water would be displaced. Hence Bates’s or Allan’s instruments would show 50 lbs. per barrel, while Richardson’s would show about 18.3; the difference being as 1 to 2.78.

Long has invented an instrument with only one weight; one side of the stem without any weight, indicating to the extent of 25 or 26 lbs. gravity; the other with the weight, going to the extent of 50 or 52 lbs. gravity. We would, however, recommend the instruments made by him on the late Mr. Richardson’s principle, as being much less liable to error than those having so many pounds indicated on one stem. The indications, however, of any Saccharometer, if accurate, may be easily compared and reduced to the scale of others by recollecting that the saccharometer indicating specific gravity per barrel, is founded on the fact that a barrel of water at 62° F. weighs 360 lbs., while the saccharometer of Allan or Bates, indicating specific gravity, has 1000 for its unit. Dividing 1000 by 360, we obtain the factor 2.78, near enough at least for practical purposes. The rule, therefore, in comparing the indications of instruments marking specific gravity to lbs. per barrel, is simply to divide the gravity shown by 2.78, and the lbs. gravity by Long’s saccharometer; or to convert Long’s gravity to the specific gravity of Allan or Bates, multiply by 2.78. Richardson’s instrument, as made by Long and other accurate makers, is sufficiently delicate for all ordinary purposes; although some may prefer an instrument indicating specific gravity, as Allan’s of Edinburgh, the invention of Professor Thomson of Glasgow College, and which is generally used by the Scotch ale brewers. The range of Allan’s or Bates’s, being 2.5 times at least, that of a saccharometer where minute attention in noting the progress of the attenuation is required, the specific gravity scale may be adopted. (See in Appendix some further remarks on an erroneous mode of taking gravities in Ireland.)