BEER. 
ing a much larger proportion of saccharine mat- 
ter is more objectionable for diabetic and dyspep- 
tic patients than porter. 
Examination of Beer—The examination of beer 
has principally for its object to estimate the 
quantity of its ordinary ingredients, and to dis- 
cover the admixture of foreign, accidental, or 
designed substances or adulterations. 
Beer ought to be perfectly clear; turbidness 
indicates either that the fermentation has not 
been complete, or that the formation of acetic 
acid has begun. The greater or less colour indi- 
cates the degree of heat to which the malt has 
been exposed and the length of time the wort has 
been boiled. The frothing, when poured out, 
depends on the variety of the beer and the man- 
ner of keeping it in casks or in bottles. Beer 
containing but little carbonic acid has a flat 
taste. The smell of beer depends on the hops, 
the malt, the alcohol, and the carbonic acid. By 
addition of common salt, and gentle heating, the 
smell of the hops is made more apparent, and 
| may be better judged of in regard to its quantity 
and quality. The taste will still better decide as 
to the quantity and quality of the hops employed, 
‘and the body of the beer. 
In examinations of beer, the amounts of the 
following ingredients are generally ascertained : 
malt extract (see the former part of this article), 
alcohol, water, and carbonic acid. The quantity 
of the last does not usually amount to more than 
O'l or 0:2 per cent. ; its exact proportion is there- 
fore often neglected, especially as its relative 
quantity is apparent from the greater or less 
frothing. In general, a quantitative estimation is 
therefore desired only of the malt extract and 
the alcohol, from which, then, the quantity of 
water results by deduction. This, in combination 
with its effect on the senses, will give a good idea 
of the quality of the beer. 
In order to ascertain the amount of malt ex- 
tract, a weighed quantity of beer is evaporated 
cautiously, and the residue weighed. It is, how- 
ever, difficult to obtain it perfectly dry, as the 
last portion of water requires a rather high tem- 
perature for its expulsion, which might cause it 
to commence decomposing. 
The amount of alcohol is ascertained by distil- 
ling a weighed portion of beer in a retort, and, 
from the weight and specific gravity of the dis- 
tilled liquid, determining its content of alcohol. 
It has already been mentioned above that 
solutions of malt extract and of sugar of the 
same spec. grav. contain an equal amount of 
solid matter. If, therefore, a weighed quantity 
of beer be heated until all carbonic acid and al- 
cohol has been expelled, and the remaining por- 
tion again diluted with water until it has attained 
its previous weight, the amount of malt extract 
may be determined from its specific gravity. If, 
moreover, the specific gravity of the beer be pre- 
viously ascertained, the amount of alcohol may 
be estimated from the difference in the two spe- 
ee 
407 
cific gravities. The contained carbonic acid 
affects the specific gravity but very slightly, and 
the greater part may be removed by gently heat- 
ing and shaking the liquid. let the specific 
gravity of a beer be found to be 1:025, and after 
the expulsion of the carbonic acid and the al- 
cohol by boiling, and subsequent dilution with 
water to the original weight of the beer, to be 
1032. The latter specific gravity corresponds to 
8 per cent. of malt extract. The difference be- 
tween the specific gravities 1:032 and 1:025 is 
0°007, which therefore will constitute the differ- 
ence in specific gravity between pure water and 
dilute spirit containing the same amount of al- 
cohol as the beer, or having the specific gravity | 
of 0:993 (1:000—0:007), which corresponds to 4 
per cent. alcohol by weight, or 5 per cent. by 
volume, as the following table will show, which 
we add for convenience : 
Spec. grav. of spirit at 63'5 Fah. 
Per ct. of alcohol. Per ct by weight. 
Per ct. by volume. 
12 ‘98 0:9834. 
1] 09817 0:9846 
10 0:9830 0:9859 
9 0:9844. 0:°9873 
8 0:9860 09887 
7 09878 0-9901 
6 0:9897 0:9915 
i) 0 9914 0 9929 
4 0:9931 0:9943 
3 0:9948 09957 
2 0:'9965 0:9971 
1 0:9982 0:9985 
It may, however, be remarked that this method, | 
in order to yield satisfactory results, requires the 
specific gravities to be taken with great accuracy, 
either by a delicate hydrometer, or a spec. grav. 
bottle, and with due regard to temperature. 
The amount of carbonic acid may be ascertained — 
by heating a weighed quantity of beer, and col- | 
lecting the expelled carbonic acid, with the neces- 
sary precautions, in a pneumatic apparatus, de- 
termining its quantity by volume, from which its 
weight may then be calculated. Another method | 
consists in introducing a weighed quantity of the || 
beer into a bottle or flask, in the orifice of which 
is fitted, by means of a perforated cork, a tube 
containing chloride of calcium, and heating very 
slowly the contents of the flask almost to ebulli- 
tion, by which the carbonic acid is expelled, while 
| 
the vapours of water and alcohol are retained by 
the chloride of calcium. The loss in weight of 
the whole apparatus before and after the experi- 
ment then indicates the amount of carbonic acid. 
If desired, the sugar and gum of the malt ex- 
tract may be separated by moderately strong al- 
cohol. The extract is first made by water into a 
thin syrup, and then alcohol added as long as 
gum precipitates, which by repetition of the 
Same treatment may be freed almost perfectly 
from sugar. The quantity of sugar may also be 
determined by the quantity of carbonic acid 
which it yields by fermentation (see the article 
Sugar). A content in the gum of unaltered starch 
may be ascertained by a solution of iodine, 
The presence of foreign substances, either 
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