Aids to the analysis of food and drugs / by T.H. Pearmain and C.G. Moor.

  • Thomas Hames Pearmain
Date:
[1895]
Catalogue details

Licence: Public Domain Mark

Credit: Aids to the analysis of food and drugs / by T.H. Pearmain and C.G. Moor. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    67/166 page 65
    Beers differ largely in their composition, according to the nature and quantity of material used in their manu- facture and the manuer in which the fermentation has been conducted. Two methods of fermentation are in use, the ' Hish' and ' Low.' _ . The ' hidi' or surface fermentation is used in England. It takes place at a higher temperature, and is of shorter duration than the ' low ' or ' sedimentary process. The ' low' or « bottom ' fermentation is largely employed in Germany. The yeast is a different variety to that used in English breweries. The beer is fermented at a low temperature, the yeast remaining at the bottom of the vat. Beers prepared by this process are highly charged with gas, and contain a much larger quantity of extractive matter and less alcohol than those prepared by the high, or Enolish process. These beers are very liable to undergo a secondary fermentation unless kept at a very low temperature. The best-known varieties of malt liquors are : 1. Pale and bitter ales, made from the finest pale malt, and bitter derived from hops in excess. _ _ 2. Mild ales, rather sweet, and containing Jess bitter and more alcohol than the pale ales. 3. Porter, a rather weak liquor coloured and flavoured with roasted malt, which gives it its black colour. 4. Stout, a stronger variety of porter. 5. Lager or German beers, prepared by the low fer- mentation process, and, as before stated, containing more extractive and less alcohol than English brewed beers. Analysis of Beer. Alcohol—Alcohol is estimated by direct distillation, or by the indirect method. Direct Distillation.—About 100 cc. of the sample is rendered just alkaline with caustic soda, a little tanuiu added (to prevent frothing), and the liquid distilled until about 90 cc. of distillate have collected. A small piece of pumice-stone or platinum-wire placed in the distillation flask will prevent bumping. The distillate is cooled to 15-5° C, made up to the 100 cc. mark with distilled water, mixed, and the specific gravity taken with a bottle or
    digitised image 1
    digitised image 2
    digitised image 3