Chemical Society. 317 



Robert Warington, Esq., Sec. Chem. Soc. This paper will be found 

 at p. 192 of the present volume. 



February 15. — The following communications were read : — 



" On a new Oxalate of Chromium and Potash," by Henry Croft, 

 Esq. For this paper also see pres. vol. p. 197. 



" Some Observations on Brewing," by Septimus Piesse, Esq. 



The author's attention was directed to the subject by the follow- 

 ing inquiry : — " Is it possible to obtain a greater quantity of extract 

 from malt by any other process than that usually followed ? Is any 

 thing left in the grains which ought to be in the wort ? " 



Now from an examination of several samples of the malt taken 

 when supposed to be completely exhausted, and from the circum- 

 stance of the grains affording such a large quantity of nourishment 

 to cattle, I was led to suspect that it was possible to increase the 

 weight of extract ; in fact, the grains were found to contain a nota- 

 ble quantity of starch. 



The non-conversion of this starch into sugar does not depend, in 

 the cases I have witnessed, upon the use of improper temperatures, 

 but arises from a deficiency of diastase (the principle which effects 

 the change of starch into sugar). In the ordinary process of brew- 

 ing, a certain quantity of water and malt are mixed together of a 

 proper temperature. After standing for a time, this water, or as it 

 is then termed, wort, is drained from the malt, and a second portion 

 of water is run on to form the second wort. There can be no doubt 

 but the principal portion of the starch is converted during the first 

 mashing, but it never is all. Now it must be remembered that as 

 diastase is soluble, it is taken up by the first wort, and when that is 

 run off, the diastase passes away also. The improvement consists 

 simply in adding diastase to the second wort, to convert the remain- 

 ing starch into sugar. This is done by the addition of a portion of 

 malt (which contains diastase) previous to mashing a second time. 

 In a brewing of 30 quarters, I should take 29 quarters for the first 

 mash, and add the remaining quarter to the second. There is such 

 an increase as to warrant me in advising its adoption by all brewers 

 and distillers. 



Another improvement in brewing is recommended by the author, 

 to prevent the absorption of oxygen by the wort, and thus in a great 

 measure prevent acidity. 



The wort, as it flows from the tun, passes into the underback, 

 according to the usual practice, where it is exposed to the air ; and 

 that for some time, because the wort must run slowly in order to 

 come bright. The improvement consists in having a float in the 

 back, that is, a surface of wood the size of the bottom of the back, 

 upon which it rests when empty. As the wort runs into the back 

 the float rises with it, and falls again when it is pumped up to the 

 copper, thus effectually keeping it out of the contact of air previous 

 to boiling, when the danger ceases. When this precaution has not 

 been taken, I have invariably found the wort to indicate more or less 

 acid, which may be looked upon as likely to lead to sour beer. 

 March 1 . — The following communications were read : — 



