Jg BULLETIN 1 
L58 V. S. DEPARTMENT OF AGRICULTURE, 
potalnslrap experimental plant 
Fitzgerald, Ga 
of the crude sirup was then added and thoroughly mixed, and this 
mixture was pumped into the cooling tank in which the crude sirup 
was stored. The sirup was then pumped into the filter press. The 
filtrate was usually clear from the start. A small belt-driven pump 
was attached to the delivery tank, with valves so arranged that the 
nitrate could be sent either to the cooling tank or to the evaporator, 
as desired. The pressure used in filtering was allowed to build up 
gradually during the filtration to about 25 pounds. 
Fifty pounds of kieselguhr proved to be nearly enough to fill the 
18 frames of the filter press. The filter cake was washed by pumping 
cold water in through the feed ports. Laboratory experiments, using 
a small filter press of the same type, showed that it was practicable to 
reignite and reuse the kieselguhr. This, however, was not done in the 
field trials at Fitzgerald. 
EVAPORATION OF FILTERED SIEUP. 
After being filtered, the sirup was evaporated to the desired 
density, using the evaporator employed for crude sirup, thoroughly 
cleaned, of course. As the dilute filtered sirup in boiling foamed 
more than the crude wort, a special procedure was evolved to over- 
come this difficulty. Unless the level of the sirup was kept rather 
low in the evaporator, it had a tendency to foam over every time 
the freshly filtered sirup was added. When a low sirup level was 
maintained, however, the steam gauge at the head of the evaporator 
coils became a convenient guide in indicating when to add a por- 
tion of the freshly filtered sirup. As the contents of the evaporator 
approached the density of the finished sirup, the steam pressure in 
tl i e „ 1 c l 0lls gradually increased to 40 or 45 pounds. As the stream 
of filtered sirup was slowly added by means of the pump, this pres- 
sure fell promptly to 30 pounds or less, owing to the greater rate 
of heat transference from the steam coils to the sirup as it became 
diluted. When the gauge indicated 30 pounds the supply of fresh 
sirup was cut off. The pressure was then again gradually built up 
to 40 or 45 pounds when the operations were repeated, the cycle of 
operations requiring about 10 minutes. The sirup was discharged 
at frequent intervals, care being taken, however, never to let the 
steam coils become exposed to the air. 
As in the case of the crude sirup, the approximate concentration 
at which to stop evaporation was shown by the flaking of a test por- 
tion poured from the testing dipper. This procedure gave a sirup 
more dilute than desirable, the Brix when cold being only about 
62.5, so that the flaking indication, although very convenient, is by 
no means as exact an indicator for the density of the hot sirup as 
the Brix spindle recommended by Dale 9 and others. The sirup 
should be concentrated to about 70° Brix (cold). 
CANNING AND BOTTLING THE SIKUP. 
The finished hot sirup was either allowed to flow from the evapo- 
rator directly into the cans or bottles and sealed or it was trans- 
ferred to a steam- jacketed copper kettle. Here it was reheated to 
the boiling point and drawn off into cans or bottles. The containers 
were washed immediately before use and the bottles were heated m 
hot water before being filled. When filled they were capped with 
the aid of a foot-power capping machine and placed on their sides 
to cool, the object being to sterilize the inner surfaces of the seals 
hy keeping them in contact with the hot sirup. 
•tl. S. Dept. Agr. Cir. 149, 1920. 
