346 CHYMISTRY APPLIED TO AGRICULTURE. 



at 20° or 22°, (probably of Reaumur,) (= 77° and 88^° 

 Fahr.) and I take care that the liquor be raised to 15° or 

 16°, {z=i specific gravity of 1.116 to 1.125,) before the yeast 

 is added to it. 



To make the leaven, which must be prepared on the 

 morning of the day in which it is to be used, I form 25 

 lbs. of rye meal into a paste with molasses, and then dilute 

 the paste with boiling water, to which I gradually add one 

 quart of pure molasses, kneading the mass thoroughly till 

 it is of the consistency of porridge : the heat of it in this 

 state should be 20° or 25°, (=r77° to 88° Fahr.) When 

 this leaven is formed for a first operation, a little beer yeast 

 or leaven of wheat flour should be added to it. The bucket 

 is covered over, and set into a place sufficiently warm to 

 produce fermentation : the yeast soon begins to swell, and 

 rises seven or eight inches in the bucket ; at the end of 

 twelve or fourteen hours it is ready for use.* The yeast 

 is thrown by small portions at a time into the vat, the 

 liquor in which is stirred during the whole time. 



Fermentation commences in the course of two or three 

 hours, and continues two or three days. 



The concentration of the liquid is gradually diminished, 

 and at the end of the operation falls to 2°t, (=: specific 

 gravity of 1.014.) 



The next process is that of distillation : the liquor is 

 poured into the boiler of the alembic through a cloth 

 strainer, by which all the meal and bran contained in it 

 are separated ; without this precaution, the liquor would 

 often ascend during distillation into the worm. 



Wheii distillation is carried on in the improved alem- 

 bics, the fi^rst alcohol which passes marks 36° (±= 0.847) 

 of the hydrometer ; it becomes gradually weaker till it 

 stands at only 10° or 12°, (= specific gravity of 1.000 to 

 0.987;) the operation is then arrested. The mixture of 

 the products forms spirit marking from 22° to 25° {zzz spe- 

 cific gravity of 0.932 to 0.906.) 



The after-taste of this spirit is so bitter as to diminish 

 its value in commerce : I have been able to correct this 



* Before making use of this j'^east, about one sixth part of it is 

 poured into a separate vessel, to be used in the next preparation of 

 yeast that may be needed ; so that in the subsequent operations only 

 20 lbs. of meal are required instead of 25 lbs. 



t Those substances foreign to the saccharine principle contained 

 in beets do not ferment ; they therefore prevent the degree of concen- 

 tration from being less than 2°. 



