The preserve of lead, copper, or zinc, sometimes observed in malt liquors, is due usually to the use of brass faucets or lead pipes by the retailer in drawing off the liquor or in filling bottles. The amount of these metals taken up by acid liquors in this way is quite small usually, but may be considerable if they are long left in contact with the metallic surface. Thus the first glass drawn from a faucet in the morning is apt to contain considerable copper and zinc in solution. In Paris the apparatus used for drawing beer is subject to supervision, and a frequent cleansing and proper kind of material is insisted on. The Brooklyn Department of Health issued an order in 1886 prohibiting the use of unprotected brass faucets in drawing beer, but its enforcement has not been insisted on.1 Analyses made for the board by Otto Grothe of ales drawn through pumps showed small quantities of copper, zinc, and lead in every case.2

Alum is sometimes used as a clarifying agent in the brewing of beer. The method of detecting the presence of the metals in liquors need not be dwelt on here. It is best performed in the ash from a large quantity of the suspected sample.

1Annual Report Dept. Health, City of Brooklyn, 1886, p. 87; and 1887, p. 63. 2 Ibid.

4450 - No. 13, pt. 3----4