TREATMENT OF FRESHLY-PREPARED VINEGAR. 



149 



through it in the direction of the arrows, whereby it is heated. 

 The thermometer t dipping into the hot vinegar indicates the 

 temperature, and the influx of vinegar is accordingly regulated 

 by opening or closing the cock c. As shown in the illustration, 



Fig. 39. 



Apparatus for heating Vinegar. 



the hot vinegar runs through the coil surrounded by cold vinegar 

 into the barrel 6, whereby it is cooled off and the vinegar in the 

 barrel preparatively heated. The pipe k, open on both ends, 

 allows the escape of the gases developed. 



In consequence of the albuminous substances becoming insol- 

 uble by heating, the vinegar running off at g is, as a rule, more 

 turbid than before. It is brought into the storage barrels, which 

 need, however, not be closed air-tight, the further processes taking 

 place in the vinegar being of a purely chemical nature and not 

 caused by organisms. The latter have been killed by heating, 

 and, together with all other foreign bodies suspended in the 

 vinegar, gradually fall to the bottom of the barrel. If the 

 vinegar after heating is allowed to lie for a sufficiently long 

 time, it clarifies completely and can be drawn off entirely bright 

 from the sediment. 



OF 



