274 HOPS. 



pulous dealers make a practice of sulphuring old, and 

 even spoiled hops, in order to give them a handsome ap- 

 pearance, and sell them either alone or mixed with good 

 hops, thus deceiving the purchaser. Consequently, in so 

 far as its use by such persons is concerned, sulphuring is 

 certainly not a commendable practice. 



Sulphured (fresh) hops can often be detected by their 

 feel and smell, and are also indicated by uniformity of colour 

 in bracts and strigs, the latter being naturally the darker of 

 the two. On the other hand, they are more difficult to 

 recognise after prolonged storage, or when mixed with 

 unsulphured hops. 



A primitive test for the presence of sulphured hops 

 consists in enveloping a clean silver spoon in a portion of 

 the suspected sample and exposing it in this condition to 

 moderate warmth for a short time. The presence of grey 

 to brown specks on the surface of the metal will indicate 

 sulphuring. 



For greater certainty, however, the method proposed 

 by Konig ^ is ' preferable, viz. : 10 grams of the hops are 

 moistened and stirred up with sufficient distilled water to 

 cover them, and are left for an hour, the stirring being 

 repeated at frequent intervals. The extract thus obtained 

 is placed in a flask with a few lumps of granulated zinc 

 and a few drops of 20 per cent, hydrochloric acid in order 

 to produce evolution of hydrogen, the formation of sul- 

 phuretted hydrogen being tested for with a strip of paper 

 moistened vyith an alkaline solution of lead acetate, which 

 turns brown in presence of the gas in question. A check 

 experiment should be made with the re-agents without the 

 hop extract. It should be remarked that only a portion 

 of the sulphurous acid absorbed by hops in the sulphuring 



' Dr. J. Konig, Die Untersuchung landwirthschaftUch und gewerblich, 

 wichtiger Stoffe, Berlin, 1898. 



