XXI. METHODS FOR THE ANALYSIS OF TEA. PROVISIONAL. 



1. Detection of Stems, Dust, and Foreign Leaves. 



Place 1 gram of tea in a 300 cc casserole, add 200 cc of water, and boll for 

 fifteen minutes. This treatment will cause the leaves to unroll, and a megascopic 

 examination will reveal the presence or absence of stems or dust, while the 

 leaves will be in condition for examination as to their form and structure. 



2. Detection of Pacing. 



Tea is faced by treating it with pigments, graphite, catechu, etc. Mineral 

 pigments can be detected in the ash, or the tea may be shaken up with a large 

 volume of water, and the water separated from the leaves by a sieve, when the 

 insoluble mineral substances used in facing will settle, and can be removed by 

 filtration for further examination, the catechu and other soluble substances 

 being in the filtrate. 



3. Preparation of Sample. 



Grind the material and pass it through a sieve having perforations 0.5 mm 

 in diameter. 



4. Moisture. 

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



5. Soluble Solids Krauch Method. 



Treat 20 grams of tea with 400 cc of water and heat on a boiling-water bath 

 for six hours. Filter through a tared filter, wash with water until the filtrate 

 measures 1,000 cc, dry, and weigh the residue. Determine the water soluble 

 substance by difference. 



6. Ash. 



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



7. Soluble Ash. 

 Proceed as directed under " X. Saccharine Products," 3 (c), page 68. 



8. Ash Insoluble in Acid. 

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



9. Alkalinity of Ash. 



Proceed as directed under "X. Saccharine Products," 3 (d) (e), page 69. 



149 



