VINEGAR FROM VARIOUS MATERIALS. 159 



One hundred kilogrammes yield, according to theory, 130.4 kilo- 

 grammes of acetic acid; in practice, after deducting a loss of 15 

 per cent, during the formation of vinegar, 110.84 kilogrammes. 



148.665 kilogrammes of alcohol (15 per cent, of loss) yield 

 164.78 kilogrammes of 100 per cent, acetic acid. 



164.78 kilogrammes of (100 per cent.) acetic acid yield in round 

 numbers 1647 liters of 10 per cent, vinegar. 



The above calculation is, however, only approximately correct, 

 as all the losses occurring in practice cannot be determined with 

 complete accuracy. 



Unmalted grain being cheaper than malt and the latter contain- 

 ing sufficient diastase to convert a very large quantity of starch 

 into maltose and dextrin, a mixture of malt and unmalted grain 

 (equal parts of both ; f grain and J malt, etc.) can be used instead 

 of malt alone. The latter is, however, preferable for the manu- 

 facture of vinegar, it yielding a product of a finer taste than un- 

 malted grain. The mode of preparing the mash is exactly the 

 same as for the distillation of alcohol, and as the necessary infor- 

 mation can be obtained from any treatise on that subject only a 

 brief sketch of the operation will be given here. 



The malt carefully ground is mixed with cold water to a thin 

 paste which is stirred until all small lumps are dissolved. This 

 mixing of the ground malt with water, or dougliing in as it is 

 called, can be effected with the assistance of a crutch or rake, but 

 best in a vat provided with a mechanical stirring apparatus. 



Doughing in being finished, water of 140 to 149 F. is per- 

 mitted to run in until the mash shows a temperature of about 

 131 to 133 F. During this operation the mash should be 

 constantly stirred. The at first thickly-fluid mass will soon be 

 observed to become thinly-fluid by the starch paste being con- 

 verted into soluble bodies. Mashing is finished in 2 to 2J hours, 

 and will be the more complete the more accurately the temperature 

 is maintained at 131 to 133 F. The completion of the process 

 is recognized by a filtered sample cooled to the ordinary tempera- 

 ture remaining colorless after the addition of iodine solution. 



The mash having reached this state, sufficient hot water is added 

 with constant stirring to raise the temperature to 140 or 141.8 F. 



