WHAT IS WINE? 
43 
influence on the character of the wine. Glycerine, however, 
besides being present in larger quantity (about one fourteenth 
part of the amount of alcohol) has a well marked sweetish taste, 
and may account for the like taste possessed by many wines that 
are perfectly free from sugar. Besides this, it seems to mitigate 
the harshness of taste belonging to several of the other consti- 
tuents of the wine, and thus to render it milder than it other- 
wise would be. On account of these properties, and not being 
liable to fermentation, it is now used extensively for the adul- 
teration of wine. 
Albumenoid Svibstances . — Grapes contain a not inconsider- 
able amount of some albumenoid substance which, like all such, 
is extremely liable to decomposition, and to induce decomposi- 
tion in other substances in contact with it. Accordingly, when 
exposed to the action of the air by the crushing of the berry, it 
absorbs oxygen and yields the ferment under the influence of 
which the sugar is transformed into carbonic acid and alcohol, 
whilst the latter may even be converted into acetic acid, the 
ferment, or yeast, absorbing the albumenoid substance and, by 
rendering it insoluble, removing it from the wine. In all white 
v ines, properly fermented, this albumenoid substance is almost 
entirely absent, having been precipitated during fermentation. 
Such wines are accordingly but little liable to further change. 
In imperfectly fermented wines, on the other hand, some albu- 
menoid substance remains dissolved, rendering the wine liable 
to fresh fermentation if not protected by an addition of spirit. 
All red wines, owing to their having fermented on the husks, 
contain, when young, much albumenoid substance, which, how- 
ever, in their case, is preserved from change by the tannin 
present. In the course of time the greater part of it is thrown 
down with the colouring matter and tannin. 
Mineral Substances , or Ash . — When wine is evaporated, and 
the dry residue left is heated for some time to a dull red heat, 
there remains a greater or smaller proportion of mineral con- 
stituents, called ash. The nature and quantity of ash left by 
a wine is one of its most characteristic features. Generally 
speaking, the total amount of ash ranges in pure natural wines 
between 1*5 and 2*5 parts per thousand. Under normal con- 
ditions this ash consists of carbonate,* sulphate and chloride of 
potassium, chloride of sodium, phosphate and carbonate of cal- 
cium, with traces of silica, magnesia, and iron ; frequently there 
are also minute traces of lithium, and sometimes of manganese. 
In many southern countries it is the custom to add plaster of 
Paris to the must ; one effect of this addition is a great increase 
* This carbonate is not contained as such in the wine, but is produced by 
the decomposition of a salt of potassium with an organic acid, such as the 
tartaric or malic acid, duriug ignition. 
