The role of moisture in coffee during storage.

The subject of fixing suitable and optimum moisture
limits in cured coffee based on scientific data, is important
in the interest of both the producer and the
consumer. This will vary with the climatic conditions
especially humidity, temperature and time. Various
studies on the different aspects of storage of coffee
have been carried out at the Institute and reported earlier
(1, 2, 3, 4, 5). These studies established that wetprocessed
coffee, if allowed to pick up moisture above
10 %, will show definite changes in appearance depending
upon the time and temperature at which it is stored
under the influence of high humidity. Even though
changes in appearance will be readily noticeable in the
case of wet-processed coffee, they will not be so in
unwashed coffee, since the colour of unwashed coffee
is already affected during drying. The figures quoted
for optimum moisture level for coffee in the literature
vary widely and often recommendations are being made
on the basis of the highest moisture content reported.
A figure of 12 % in cured coffee has also been recommended.
Our earlier studies have indicated that
optimum moisture should be based on climatic
conditions, types of storage, temperature and period
during which coffee should be stored. With high
humidity and high temperature, the appearance is
affected faster than with low temperature and low
humidity. Systematic data have been obtained by us
by storing lots of about 10 tons in a dry place as well
as in a high humidity place. This note reports the observations
made.