le of the water-soluble
material.[180]

TABLE IV--ANALYSIS OF SANTOS COFFEE EXTRACT
(DRY BASIS)

Ether extract, fixed 1.06%
Total nitrogen 3.40%
Caffein 5.42%
Crude fiber 0.25%
Total ash 17.43%
Reducing sugar 2.70%
Caffetannic acid 15.33%
Protein 7.71%

It is difficult to make the trade terms, such as acidity, astringency,
etc., used in describing a cup of coffee, conform with the chemical
meanings of the same terms. However, a fair explanation of the cause of
some of these qualities can be made. Careful work by Warnier[181] showed
the actual acidities of some East India coffees to be:

TABLE V--ACIDITY OF SOME EAST INDIA COFFEES

Coffee from Acid Content
Sindjai 0.033%
Timor 0.028%
Bauthain 0.019%
Boengei 0.016%
Loewae 0.021%
Waloe Pengenten 0.018%
Kawi Redjo 0.015%
Palman Tjiasem 0.022%
Malang 0.013%

These figures may be taken as reliable examples of the true acid content
of coffee; and though they seem very low, it is not at all
incomprehensible that the acids which they indicate produce the acidity
in a cup of coffee. They probably are mainly volatile organic acids,
together with other acidic-natured products of roasting. We know that
very small quantities of acids are readily detected in fruit juices and
beer, and that variation in their percentage is quickly noticed, while
the neutralization of this small amount of acidity leaves an insipid
drink. Hence, it seems quite likely that this small acid content gives
to the coffee brew its essential acidity. A few minor experiments on
neutralization have proven that a very insipid beverage is produced by
thus treating a coffee infusion.

The body, or what might be called the licorice-like character, of
coffee, is due conceivably to the presence of bodies of a glucosidic
nature and to caramel. Astringency, or bitterness, is dependent upon the
decomposition products of crude fiber and chlorogenic acid, and upon the
soluble mineral content of the bean. The degree to which a coffee is
sweet-tasting or not is, of course, dependent upon its other
characteristics, but probably varies with the reducing sugar content.
Aside from the effects of these constituents upon cup quality, the
influence of volatile aroma