Ii6 



Journal of Agricultural Research 



Vol. XV. No. 3 



ACIDITY IN THE WATER AND THE ALCOHOLIC EXTRACTS OF SILAGE, 

 TITRATING TO PHENOLPHTHALEIN 



Twenty- five cc. of the water or the alcoholic extract, representing 5 

 gms. of silage were pipetted into a 500-cc. Jena Erlenmeyer flask, and 200 

 cc. of carbon-dioxid-free water were added. One cc. of phenolphthalein 

 as indicator was used. The extract was then titrated to a faint pink 

 with N/20 sodium hydroxid. The results obtained are presented in 

 Table III. 



TablS III. — Acidity in water and alcoholic extracts of silage 



[Results expressed as cubic centimeters of Nho sodium hydroxid on the extract from 5 gm. of silage titra- 

 tion with phenolphthalein as indicator] 



Ace of silage. 



Days 



o 



I 



2 



3 



4 



6 



7 



8 



10 



13 



15 



17 



21 



29 



43 



64 



Alfalfa alone. 



Water. 



3-3 

 9.0 



10. 4 



11. 4 

 9. I 



10. 6 

 14.4 

 "•5 

 13-4 

 17.8 

 18. 5 

 16.6 

 18. I 

 20. 8 

 26.6 



25-7 

 26. 7 



Alcohol. 



7-7 



11. 7 



12. o 

 12. 9 



13-5 

 14.9 



15-4 

 15-0 

 16. 9 

 19. o 

 19.9 

 20.8 

 22. 4 

 25. 2 

 28.4 

 30-4 



Sweet clover alone. 



2.8 



4.6 



3-4 

 6.3 

 8.7 

 8.0 



6.4 



11. 6 



II- 3 

 10.3 



12. 2 

 13-8 

 13.0 

 II. 7 

 12.6 

 12.8 



Alcohol. 



3-6 

 6. I 

 7.2 

 8.7 

 10. I 

 9.4 



9 9 



12- S 

 12. 8 



13.6 

 14.7 

 15-5 



16. 5 



16.5 

 17.7 



18. 5 



Sweet clover and corn- 

 chop. 



Water. 



13. 2 



9-3 



13.2 



14-3 

 14.8 

 16.6 

 17. o 

 16.8 

 18.9 

 18.6 



Alcohol. 



3-8 



5-7 



6.9 



7.6 



10. o 



10. 9 



14. 8 

 13.2 

 16. I 

 17-3 

 17-3 



20. o 



21. o 



22. 4 

 25. 2 

 26.3 



The figures in Table III show the following results: 



(i) The acidity in the alcoholic extract appears to be uniformly 

 greater than in the water extract. The silage made from sweet clover 

 alone and from sweet clover plus com meal show the same relative 

 differences in the acidity of the alcoholic and water extracts as the silage 

 made from alfalfa alone. That the alcoholic extract from com silage will 

 give a larger percentage of acidity than will the water extract when 

 phenolphthalein is used as the indicator has been shown in a previous 

 publication from this laboratory.^ A suggestion was reported in that 

 joumal that the greater acidity of the alcoholic extract is due to fatty 

 acids liberated by lipases which are active in silage formation. That 

 this explanation is probably not correct will be shown in a subsequent 

 part of this paper. 



' SwANSON, C. O., Calvin. J. W., and Hungerford, Edwin, aodity in silagb: method op 

 DBTERMiNATiON. Jour. Amer. Chem. Soc, V. 35, no. 4, p. 476-483. 1913. 



