150 CASEIN. 



tion of the liquid contents, or at any rate against their 

 acquiring a flavour due to the cask. In the case of beer 

 barrels, it has long been the practice (in some parts of the 

 Continent) to line them with pitch, which, however, is liable 

 to crack and peel off, so that not only is the beer contam- 

 inated with fragments of pitch, but the cracks in the coating 

 afford an excellent harbouring place for the development of 

 bacteria. It is true that shellac dissolved in spirit has also 

 been used for varnishing the interior of these casks ; but that 

 process in turn has drawbacks which preclude its employ- 

 ment in many cases. 



It is an essential condition of the good cask lining that 

 the coating shall adhere strongly to 'the wood, and be in- 

 soluble in any of the liquids coming under consideration. It 

 must not impart to them any taste or smell, and, finally, 

 must form a smooth coating resembling glaze, without any 

 tendency to crack or peel. 



Such a preparation has been made by the Union Aktien- 

 gesellschaft fur Chemische Industrie, of Vienna, in the form 

 of a solution of casein and formaldehyde, which is claimed to 

 be an efficient substitute for pitching, paraffining or varnish- 

 ing beer and wine casks. 



According to this patented process, the casks are lined 

 with a small quantity of an ammoniacal solution of casein 

 (glue and gelatine), containing a little formaldehyde, this 

 mixture being shaken up in the cask for a short time and 

 then allowed to drain. The casks are next dried by the 

 admission of heated air, and are finally swilled out with 

 formaldehyde solution, in order to render the film of casein 

 perfectly insoluble. 



Exhaustive experiments have demonstrated that the beer 

 will keep, in the casks so treated, quite as well as in those 

 lined with pitch. 



The absolutely staunch casein coating prevents any loss 



