UTILIZATION OF GRAPE POMACE AND STEMS. 5 
oil, the meal and tannin extract being of secondary importance in 
point of actual value. 
of this waste material 
to the various com- 
mercial products men- 
tioned. 
CREAM OF TARTAR 
FROM GRAPE 
STEMS. 
The method of ex- 
tracting the cream of 
tartar from the stems 
consisted in boiling 
the ground stems with 
an excess of water, 
running off the water 
extract, and concen- 
trating it at atmos- 
pheric pressure or by 
means of a vacuum 
pan to the consistency 
ofathin sirup. When 
allowed to stand, this 
extract deposited crys- 
tals of cream of tar- 
tar, which were 
thrown on a force 
filter or into a centri- 
fuge and washed with 
cold water, in which 
the crystals are oniy 
shehtly soluble. In 
this manner about 2 
per cent of crude 
cream of tartar was 
obtained. The washed 
crystals were readily 
The diagram (fig. 3) illustrates the reduction 
Odes temming 
: 660 TONS 
Hea cing 
Extractsn 
PLESSING 
Dry/ng ANT 
Separa cing 
DRY SKINS SLEDS 
/650 7ONS /100 TONS 
HEN aba 
Manuka ctusing EXtracty/. 1G 
y \ poo \ 
O/L 
132 TONS } 
Fic. 3.—Diagram showing the products obtainable from 
grape waste. 
purified by recrystallization from a hot-water solution. 
The total quantity of wet stems (660 tons) would yield, therefore, 
about 13.2 tons of crude cream of tartar, which, at 40 cents a pound 
(a conservative figure for the crude crystals), would bring a gross 
revenue of $10,560. 
* All estimates and prices quoted hereinafter, unless otherwise specified, are based on 
prices obtaining in the winter of 1919-20. 
