in Clearing Malt Liquor. 107 



(the one-fourth of an ounce, for instance), are to be cut into 

 very small pieces, and each one-fourth of an ounce put into 

 half-a-pint, (imperial measure) of hard or sour beer, and 

 the several vessels containing the different samples put into 

 an apartment, at from 65° to 75° F., and allowed to remain 

 there for three days, stirring each sample very well, once or 

 twice a-day. 



At the expiration of that time, there will be an evident 

 difference in the strength of each jelly, provided different 

 qualities of Isinglass had been submitted to the experiment, 

 and when the thickest jelly has a small quantity of the 

 tincture of galls applied to it, and stirred through it, it will 

 separate the gelatine from the sample of Isinglass in the 

 form of a thick jelly. The other samples which afforded a 

 less solid jelly, will give, with tincture of galls when stirred 

 through it, a smaller quantity of gelatine in the form of 

 thick jelly. 



From the strength of the jelly given, by any sample of 

 Isinglass steeped in the above proportion of sour beer, (such 

 as brewers use in making clearings), and submitted to a 

 temperature not exceeding 75° F., may be ascertained the 

 relative value of that sample, as upon the strength of the 

 jelly, and, consequently, the quantity of gelatine contained 

 in any Isinglass, depends its value in clearing malt liquor. 

 The best short-staple Isinglass is always soluble in boiling 

 water to about ^ residue. 



In the preparation of brewers' clearings, Isinglass, of a 

 good quality, is steeped in acid beer, in an apartment of 

 about 50° F. temperature. After some time, the Isinglass 

 is converted into a jelly by the acidity of the hard beer, it 

 being one of the qualities of gelatine to be soluble in dilute 

 acids. 



An advantage arises to the brewer, in always making his 

 clearings from sour beer of an uniform strength of acidity, 

 by which means he is protected from any disappointment 

 resulting from the strength of the clearings he uses, pro- 

 vided he was previously aware of the good quality of the 

 Isinglass, he submitted to the action of the sour beer. 



A simple method may be taken to try the acidity of malt 

 liquor, of which a brewer intends to make clearings. Make 

 a standard liquor of one part (by weight) of the bi-carbonate 

 of potash, dissolved in sixteen parts (by measure) of water. 



