UTILIZATION OF GRAPE POMACE AND STEMS. 17 
than the resulting meal from the solvent extraction. The latter con- 
tains a large percentage of fiber, which practically precludes its use 
as a feeding material, and it could be used only as a fertilizer. 
EXTRACTING TANNIN FROM THE HULLS. 
The astringency of grape seeds is well known. This is due to the 
tannin in the hulls, which is present to such an extent as to affect 
unfavorably the stock-feeding value. 
In order to determine the quantity of tannin obtainable from the 
hulls the ground hulls were macerated with water at 35° to 40° C. for 
O/L FINISHING SOLVENT RECOVERY A 
STILL STILL 
STORAGE | SPACE 
FOR RAW | MATERIAL 
Fig. 10.—Oil-extraction plant, with rotary percolator extractors. 
12 hours, then percolated, and the extract concentrated in vacuo. 
By this means 10 per cent of a soft extract was obtained, which 
showed 47.5 per cent total solids, 45.2 per cent soluble acids, 2 to 3 
per cent insolubles, 15.5 per cent tannin, and 29.7 per cent nontannin. 
This extract was submitted to a large tannery for testing, and the 
results of the test on leather showed good tannage with excellent 
color. 
In view of the present need for tannin extracts, it appears prob- 
able that the hulls resulting from the decortication of grape seeds 
could be thus utilized. The total quantity of hulls available would 
