64 The Fermentation of Cacao 
was furnished by the bacterial growth, or, what 
is less probable, by the yeast cells. 
The “fermentation ” should not take longer 
in Porto Rico than fifteen to twenty hours, 
while in some sections of Central America, as 
Guatemala, it must be carried on for two days! 
Undue prolongation of the fermentation must 
be avoided, as otherwise a brown colouration 
of the parchment and of the seeds is produced, 
and the seeds would further acquire a disagree- 
able odour—two circumstances which render 
the product unfit for market. 
After the fermentation and washing, the 
parchment coffee is readily dried, either on 
cement floors exposed to sun and air, or better 
in rotating cylinders through which warm air 
passes. At a certain degree of dryness the 
parchment becomes brittle and breaks easily 
in the milling process, which thus removes the 
parchment envelope and silver skin from the 
seeds. In fact the milling must be done 
while the parchment is still warm. 
This milling is in many cases done in 
London and not in the country where the 
coffee is produced. Better preservation of 
the shape and colour of the bean has been 
' When carrying out these investigations Dr. Loew 
was Physiologist: to the Porto Rico Agricultural Ex- 
periment Station, and this essay or report was first 
published in the Annual Report for 1907 of that station, 
and afterwards reprinted separately, as pamphlet 1093 
by the U.S. Dept. of Agriculture. 
