20 BULLETIN 1158, TJ. S. DEPARTMENT OF AGRICULTURE. 
Sweet-potato sirup made in this manner is bland and sweet, with 
a distinctive flavor. It is not as sweet as cane sirup, cane-sugar 
sirup, maple sirup, honey, or high-grade molasses. A satisfactory 
degree of sweetness is secured, however, by mixing 100 parts of the 
sweet-potato sirup with from 10 to 15 parts of any one of the fore- 
going sirups. Other flavoring materials, such as imitation maple 
flavor and vanillin, were less satisfactory for this purpose. 
In flavoring various lots of sweet-potato sirup, the freshly-made 
hot sirup was poured into a steam- jacketed copper kettle, the flavor 
was added, and the mixture was heated, with stirring, to the boiling 
point, when it was drawn off into the containers and sealed. 
YIELD. 
In the six runs made at Fitzgerald during the spring of 1921, in 
which a total of 8,892 pounds of warehoused Porto Rico potatoes 
were used, the average yield of crude, unfiltered sirup was 1.55 gal- 
lons to each 50-pound bushel of potatoes. This yield was calculated 
in terms of 72 per cent solids in the sirup. During the first part of 
1922 the yield of finished sirup in the final containers on the same 
basis was 1.37 gallons to each 50-pound bushel of potatoes. As no 
special pains were taken to secure high yields, this yield no doubt is 
low. Attention was paid mainly to the production of sirup of 
uniform high quality. In the practical production of sweet-potato 
sirup the two most important factors were (a) the use of the proper 
quantity of water in mashing, and (b) the technique of the pressing. 
Water is required to facilitate the mashing of the potatoes into pulp 
by the action of the stirrer arms and to give the pulp the necessary 
fluidity so that it will flow from the mash tank and press readily. 
All things considered, the best quantity is the equivalent of the 
weight of potatoes taken. For best results, the press cakes should 
be thin, not more than 3 inches thick when laid up, and should be 
of uniform thickness. Sufficient time for drainage while under high 
pressure should be allowed. 
PRODUCTION OF SWEET-POTATO SIRUP ON THE COMMERCIAL 
SCALE. 
Although the cost of manufacturing sweet-potato sirup at the ex- 
perimental plant at Fitzgerald, Ga.. was naturally too high for com- 
mercial purposes, the data thus obtained formed the basis for esti- 
mates on the cost of manufacturing sweet-potato sirup in an im- 
proved plant. The proposed plan for a sweet-potato sirup plant 
makes use of the ideas based on improved practices and on the data 
and information secured in the experimental semicommercial plant. 
The capacity of the proposed plant was set at 100 gallons of plain 
sweet-potato sirup per 10-hour day, which is the common working 
day in the sweet-potato sections of the South. A plant of this ca- 
pacity was taken because in general it would seem to be most prac- 
tical with the sweet-potato curing house of average size. Sirup 
plants are probably most practical in connection with sweet-potato 
curing houses where culls can be utilized for making the sirup. 
