Laboratory notes. Sanitary chemistry and water analysis .. by Richards Ellen H

Author:Richards, Ellen H[enrietta (Swallow)] "Mrs. R. H. Richards," 1842- [from old catalog]
Language: eng
Format: epub, pdf
Tags: Food, Water
Publisher: [Boston
Published: 1896-03-25T05:00:00+00:00

23 EXAMINATION OF FERMENTED LIQUORS.

WINE.

Effervescing wines should, before analysis, be vigorously shaken in a large flask, to remove carbon dioxide.

Specific Gravity. — Specific gravity is taken by means of the pyk-nometer or Sprengel tube at 15.5° C.

Alcohol by Weight. — About 50 cc. of wine are weighed in a 150 cc. wide-mouth stoppered bottle, and transferred with 100 cc. water to a 500 cc. round bottom distilling flask. Free acid is neutralized with sodium hydrate, and 0.5 gram tannin added to prevent frothing. About 100 cc. of liquid are distilled over into the 150 cc. flask, which should be provided with a cork, perforated to receive the condenser-tip, and carrying a mercury valve to prevent loss of alcohol. The distillate, after being thoroughly mixed, is weighed, the specific gravity taken, and the percentage of absolute alcohol by weight corresponding to it found in the tables.

Calculation of Results. — Calling A the percentage of absolute alcohol in the sample, a that in the distillate, W and w their respective

weights, then A = ^^. If the specific gravity of the wine is known,

weighing may be avoided by carefully measuring both sample and distillate at 15.5° C. The corresponding percentage of alcohol by volume may be found in the tables.

Extract — Dry Wines. — About 50 cc. are weighed in a small flask, transferred to a platinum dish having a flat bottom, and evaporated on the water bath to the consistency of sirup. The residue is then heated in the oven at 100° C. for two hours and a half, cooled in a desiccator, and weighed.

Sweet Wines. — Of these only 10 cc. are weighed, diluted to 100 cc, and 50 cc. evaporated as above described.

Ash. — Ash maybe determined by igniting the extract at a very low red heat and weighing.

Free Acids — Total Acidity Calculated as Tartaric Acid. — 10 cc. of wine are titrated with ^\ sodium hydrate. The end-point is reached when a drop of the liquid placed upon faintly red litmus paper produces a blue spot in the middle of the portion moistened. Number of cc. y'ij sodium hydrate used X -0075 = weight in grams of all acids reckoned as tartaric acid.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.