COFFEE. 153 



6. Moisture. 

 Proceed as directed under " VI. General Methods," on page 38. 



7. Soluble Solids Winston's Method. 



Place 4 grams of the sample in a 200 cc flask, add water to the mark, and 

 allow the mass to macerate for eight hours, with occasional shaking; let stand 

 sixteen hours longer without shaking, filter, evaporate 50 cc of the filtrate to 

 dryness in a flat-bottomed dish, dry at 100 C., and weigh. 



8. Ash. 

 Proceed as directed under " VI. General Methods," on page 38. 



9. Soluble Ash. 

 Proceed as directed under "X. Saccharine Products," on page 68 (c). 



10. Ash Insoluble in Acid. 

 Proceed as directed under " XXIV. Spices," page 162. 



11. Chlorin. 

 Proceed as directed under " III. Inorganic Plant Constituents," page 23. 



12. Alkalinity of Soluble Ash. 

 Proceed as directed under "X. Saccharine Products," page 69 (d). 



13. Soluble Phosphates in the Ash. 



Determine phosphoric acid (P 2 O 6 ) in soluble ash, as directed under " I. Fer- 

 tilizers," page 1. 



14. Insoluble Phosphates in the Ash. 



Determine phosphoric acid (P 2 O B ) in the insoluble ash as directed under 

 " I. Fertilizers," page 1. 



15. Protein. 



Determine nitrogen in 3 grams of the sample by the Kjeldahl or Gunning 

 method (page 5, under "I. Fertilizers"). This gives the total nitrogen due 

 to both the proteids and the caffein. To obtain the protein nitrogen, subtract 

 from the total nitrogen the nitrogen due to caffein, obtained by direct determina- 

 tion on the separated caffein or by calculation (caffein divided by 3.464 gives 

 nitrogen). Multiply by 6.25 to obtain the amount of protein. 



16. Caffein Hilger and Fricke Method. 



To from 5 to 10 grams of coffee add 100 cc of water and boil, filter, and treat 

 the residue twice more with boiling water. Add to the united filtrates an excess 

 of lead acetate, filter, and wash. Treat the filtrate with hydrogen sulphid to 



a Arch. Pharm., 1885, p. 827. 



