90 



known original specific gravity. But by a study of the principle 

 involved in this table, and by comparison with standard tables on spe- 

 cific gravity and relative sugar content, and the actual analyses, Table 

 No. XIII has been constructed. By it an operator may determine 

 at any reading, between 1.040 and 1.070 on a standard hydrometer, 

 the probable sugar content present, and the approximate alcoholic 

 strength of the liquor. Thus he is enabled to know how the fermen- 

 tation is progressing. As a cellar guide this will be a very important 

 help, and by reference to it the later discussion on the manipulation 

 of the must will be more intelligible. 



As a basis for this table it was assumed that a must reading 1.040 

 specific gravity, contains 8 per cent of sugar. Kramer says 9 per cent, 

 but this is surely too high for apples. Power says 8.9 per cent, which 

 is also too high, at least for American fruit. Kramer's table then allows 

 1 per cent increase in sugar for each 5 points (0.005) on the hydrom- 

 eter, but this if logically carried out requires that the nonsaccharine 

 solids increase proportionally more rapidly than the saccharine sub- 

 stances. Analytical data are against this theory; hence, it has been 

 estimated that the sugars increase 1.05 per cent for the first 5 points 

 above 1.040, and be3 r ond that at an increasing ratio found by adding 

 an additional 0.05 per cent of sugar for each subsequent 5 points 

 (0.005) on the hydrometer. 



But turning to the subject of relative decrease in sugar content 

 below 1.040 it becomes necessary to allow a loss of 1 per cent for each 

 0.005 on the hydrometer in order to exhaust the 8 per cent of sugar at 

 unity 1.000 on the hydrometer. Yet, as there are solids other than 

 sugar present, it is altogether improbable that this will show the true 

 percentages if the liquid is considered to be water; but it really con- 

 sists of a mixture of two liquids, water which constitutes much the 

 greater part, and alcohol which is lighter than water and which enters 

 into the mixture in a constantly increasing proportion as fermentation 

 progresses. Hence, for a must originally showing 8 per cent of sugar, 

 it is probable that unity (1.000 on the hydrometer) will about bring it 

 to diyness; rt but by the same reasoning richer musts will not come to 

 entire dryness at unity. This the table shows when carried out on the 

 principle that for each 1 per cent of sugar lost, 0.5 per cent of alcohol 

 is formed. This ratio of alcohol for fermentable sugars is only 

 approximately correct. 



In using this table as a cellar guide, one notes in the left hand col- 

 umn the hydrometer reading corresponding with the original density 

 recorded for the must, and then finds in the box heads the present 

 reading of the hydrometer; the figures for sugar and alcohol percent- 

 ages at the intersection of the lines from these two readings will 

 show approximately the present condition of the must as to alcohol 

 and sugar content. 



a In the technical phrase of fermentation work " dryness " means total absence of 

 sugar. 



