SUGAR-CANE SIRUP MANUFACTURE 65 
not advisable. Although the cost of invertase is small, sirup con- 
- centrated to a higher aencite than customary contains less water 
and is therefore worth correspondingly more per gallon. If the 
sirup producer does not care to pack his sirup in cans and market 
it himself, and if he has no satisfactory market for shipment in 
barrels at the time the sirup is made, it is sometimes desirable to 
barrel the sirup at a higher density than customary so that it will 
keep for a longer time without danger of fermentation—until such 
time, for instance, as it is anticipated that sirup will command a 
better price. The use of invertase in this manner offers an economical 
alternative to cold-storage warehousing. 
Experiments have shown that at a density of 43° Baumé (79.8° 
Brix), measured at ordinary temperature, cane sirup does not readily 
ferment in warm weather. At this density the sirup contains 21 to 
22 per cent of water; at ordinary density it contains 28 to 30 per 
cent of water. A sugar-cane sirup containing as little as 21 per 
cent of water, however, will usually crystallize to a pronounced 
degree. The use of invertase makes it possible to concentrate such 
a sirup to the density required to retard fermentation without the 
attendant danger of excessive crystallization. Wor sirup having a 
water content of 21 to 22 per cent the “apparent purity” should be 
about 45. The production of sirup of unusually high density, while 
not recommended as the best everyday practice, may prove advisable 
at times for holding sirup in bulk for a better market. 
La Cuite, a product closely resembling sirup, is highly esteemed in 
Louisiana and would doubtless be in much more extensive demand if 
manufactured in such a way as to prevent excessive sugaring. As 
this product is made on a comparatively large scale in Louisiana, the 
customary process of clarification with sulphur dioxide and lime is 
employed. A sufficient quantity of invertase is added to the semi- 
sirup to reduce the apparent purity from approximately 70 to 30 in 
the 12-hour period. ‘The sirup may then be evaporated to a density 
of 86 to 87 per cent solids, or a water content of 13 to 14 per cent, 
when it is known as La Cuite. The proper application of invertase 
events excessive sugaring, even in products of this extremely high 
ensity. 
e USE OF INVERTASE BY CANNING PLANTS 
The variation in quality of farm-made sirup is a serious obstacle to 
the successful marketing of any surplus sirup remaining in the local 
market, unless the surplus sirup is barreled and sold to large packers 
and sirup distributors (p. 2). 
The invertase method, with certain modifications, is useful at 
canning plants in case the sirup received undergoes crystallization 
when packed at the density preferred by the market. The equip- 
ment used in an ordinary sirup-canning plant may be used, and the 
cost of operation is but little greater. Figures 18 and 19 show the 
floor plan and sectional end view of such a canning plant, designed by 
the Bureau of Chemistry, which has been in successful operation. 
The essential difference between this plant and the usual canning 
plant consists in the installation of three large mixing tanks instead 
of only one. In both cases space is required for storing barrels of 
sirup and for grading, for installing the canning machinery, process- 
| ing pan (or evaporator) and cooling tanks, and for storing empty 
| cans and canned and crated sirup ready for shipment. 
56750° —257 5) 
