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 ])e 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 



OIL r/msHiMG soLvsAn-/!Ecot'£Rr A*- 



'mmm:nrnmmmm)mm>iiwm)m)iw//. 



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. v>hich 

 showed 47.5 per cent total solids. 45.2 per cent soluble acids, 2 to 3 

 per cent insolubles, 15.5 jier 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 



