4 BULLETIN 538, U. S. DEPARTMENT OF AGRICULTURE. 
a hydrometer graduated in salt percentages, Baumé scale, or specific 
gravity. Hydrometer readings should be taken only in cool brines, 
the temperature of which is as near 60° F. as possible. With these 
instruments the packer can determine readily by a few experiments 
the best brine and the best temperature as related to time of cook- 
ing. Cooking for 15 minutesina 15 per cent brine might be used > 
a starting point in these experiments. 
The following table shows the approximate relationship be ween 
the boiling points, densities, and specific gravity of the brines, and 
the amounts of salt needed to make a brine of given percentage. In 
ordinary practice, however, it is necessary to have from 10 to 20 per 
cent more than the specified amount of salt. As commercial salts 
vary in impurities and moisture content, this table is suggested only 
asaguide. It must be modified after experiment to fit the particular 
salt used. 
TaBLe 1.—Approximate relationships between bowling points and strength of brine. 
| 
| : Dry salt 
| Boilin epee Density | required 
Salt. | point of | SV" ¥ | of brine | for 100 
| brine. at 60° F. | 2t 60° F.| gallons 
| of brine. 
Per cent. I De ° Bau A Pounds. 
5.0 214 1.035 5.0 43 
7.5 216 1. 054 7.4 65 
10.0 217 1.073 9.8 86 
12.5 219 1. 092 12.2 113 
15.0 221 1.112 14.5 139 
17.5 223 1.131 16.7 165 
20.0 225 1.152 19.0 191 
25.0 228 1.192 23.2 | 230 
COOKING WITH LIVE STEAM. 
Live steam, occasionally used for cooking headed shrimp that are 
intended for drying, may also be employed in cooking shrimp for 
ordinary purposes. The shrimp are sprinkled evenly with salt and 
allowed to stand ashort time. They are then placed in a steam-tight 
box and subjected to the action of live steam for half an hour. This 
process, aside from obviating the necessity for making and handling 
brines, requires less salt, prevents soaking out of flavors, and results 
in less loss in weight. Where brine is used, chemical analysis of the 
scums and brines after cooking shows that considerable amounts of 
albuminous and mineral matter have passed from the shrimp into 
the brine. The albumin coagulates upon boiling in much the same 
manner as does the white of an egg. This loss in albuminous and 
mineral matter means that the shipper loses, since he has fewer 
pounds of shrimp to ship, and that the consumer does not receive 
the full food value of the product. 
