This section is from the book "Alcohol, Its Production, Properties, Chemistry, And Industrial Applications", by Charles Simmonds. Also available from Amazon: Alcohol: Its Production, Properties, Chemistry, And Industrial Applications.
Fifty c.c. of the distillate are titrated with decinormal soda solution, using one drop of phenolphthalein solution as indicator. The acid is calculated as acetic (c.c. N /10 soda used x 0006 X 2 = acetic acid in grams per 100 c.c. of distillate). To express the result in the customary form as milligrams per 100 c.c. of absolute alcohol, it must be multiplied further by the factor
1,000 x 100 / per cent. of alcohol by volume in distillate