372 
equal depth of colour equal quantities of chlorate of potash 
he gradually added, the malt first becomes a much paler 
orange, and then pale yellow ; whereas the liquorice turns to 
an orange, which does not become pale until very much more 
chlorate has been added than suffices to make the malt very 
pale. Though they can thus be easily distinguished, yet 
when mixed together, as in porter, it is not easy to obtain 
decided results. The change of colour is very similar in 
kind, and differs only in degree ; so that the addition of too 
much chlorate may make the liquorice as pale an orange as 
the malt ; and when not much liquorice occurs mixed with 
malt, it becomes very difficult to recognise it. Still, how- 
ever, with care its presence may be detected in ordinary 
porter. 
That colouring matter of porter which is soluble in strong 
alcohol behaves with reagents like a mixture of those from 
beer and dark malt. Hypochlorite of soda turns the solution 
in suljfiiuric acid to a red, but of a less deep tint than in the 
case of beer. 
The sweet wort obtained in brewing contains the colour of 
malt, already described, and, after boiling with hops, the hop 
colour; but after fermentation a change is found to have 
occurred, which proceeds still further when the beer is kept 
in the barrel. This change is best shown by the addition of 
hypochlorite of soda to the solution of the colouring matter 
in sulphuric acid. The gum, &c., should be removed by 
means of alcohol, in the manner already named when de- 
scribing malt. Taking two experiment- cells, and dissolving 
in one the colour of the unfermented wort, and in the other 
an equal quantity of the colour of beer that has been kept 
some months in barrel, the general tint is seen to be very 
similar. Since the solutions are otherwise apt to be turbid, 
it is best to fill the tubes three fourths with the sulphuric 
acid diluted with an equal bulk of water, and then to fill up 
with alcohol, after which the coloured syrup can be added on 
a platinum wire, and made to dissolve by stirring. On adding 
little by little hypochlorite of soda to such a solution of the 
unfermented wort, it first turns it a little more orange, and 
then pale yellow ; whereas, in the case of the beer kept in 
barrel, it is first gradually changed to a deep pink-red, 
which, when strong, is 3 . - 4 — , and when seen to the greatest 
advantage is 5 - - 74- ... 9-£ - - 10 — , having, therefore, a 
broad absorption-band at 6}. On adding more hypochlorite 
it becomes more orange, and finally an orange-yellow. The 
fermented wort behaves in an intermediate manner; and 
hence it should appear that the change begins during fer- 
