PRODUCTION OF SIRUP FROM SWEET POTATOES. 31 
Table 10. — Cost of manufacturing sweet-potato sirup in 1-pint bottles. 
Cost items. 
Plain 
sweet- 
potato 
sirup (100 
gallons; 
Artificial- ror ,„ fl „ 
-srsr 
Cost of manufacturing sweet-potato sirup, exclusive of containers . 
Additional labor (3 men at SI. -50 per dav, 
800 pint bottles at $4.17 per 100 
800 caps at $0.35 per 100 
800 wrappers at S0.26 per 100 
800 labels a t $0 . 165 per 100 
66.67 cases at $0.31 each 
3.4 sacks of cottonseed hulls at $0.80 per sack 
888 pint bottles at $4.17 per 100 
888 caps at $0.35 per 100 
888 wrappers at $0.26 per 100 
SS* labels at SO. 165 per 100 
74 cases at S0.31 each 
3.77 sacks of cottonseed hulls at $0.80 per sack. 
$64.31 
4.. 50 
33.36 
2. n0 
2 - 
1.32 
20.67 
2.72 
$73 • 3 
4.. 50 
33.38 
- • 
2. OS 
1.32 
20.67 
2.72 
Total cost 
Cost per gallon 
4.50 
37.03 
3.11 
2.31 
1.47 
22.W 
3.02 
PRECAUTIONS TO BE OBSERVED. 
Although the method used in making sirup from sweet potatoes 
is simple, the following precautions must be taken to insure the pro- 
duction of sirup of fine quality : 
Use pale distillers' malt in the proportion of from one-tenth to 
one-fifth of 1 per cent of the potatoes taken. 12 
Use washed potatoes, free from decay. 
Use kieselguhr as a filter aid. 13 
In cooking, reject the condensed water flowing from the mashing 
tanks. 
Use no wooden equipment in the pores of which potato juice has 
been allowed to decay. 14 
Clean equipment often enough to avoid all danger of spoilage. 
Arrange equipment so that it can be cleaned readily. 
Once the operations are started, complete the process without 
delay. 
Avoid letting the sirup thicken or bake on the evaporator 15 coils. 
12 Investigation of the action of the malt showed that to avoid the strong flavors 
which some kinds of malt impart it was desirable to use a light-colored distillers' malt 
and to reduce the malt requirement to a minimum. The quantity of commercial pale 
distillers' malt required was only from one-tenth to one-fifth of 1 per cent of the weight 
of the potatoes. The principal reason for this very small requirement was that the 
sweet potato has a very active diastase which digests a large proportion of the starch 
while the potatoes are bein^r heated. 
15 The laboratory results indicate that in filtering the kieselguhr (diatomaceous earth), 
used as a filter aid, should be ignited at a low red heat as recommended by Caldwell 
(U. S. Dept. Alt. Bui 1025) as a satisfactory method for eliminating the peculiar flavor 
which the untreated material seems to impart to the sirup. The kieselguhr. if reignited 
between each use, could be used repeatedly. 
14 The laboratory work also showed the necessity of taking care that the hot wort or 
sirup never comes in contact with the wooden BurCaces of racks, pressure platform, or 
other equipment, in the pores of which potato juice has been allowed to decay, as such 
contact is likely to cause contamination in flavor. 
15 The laboratory work showed that color and flavor were injured by allowing the sirup 
to bake on steam-heated surfaces, this work leading to better' evaporating practice. 
