CANNING SARDINES 105 
method of preparing the fish.°* The general results of this work are 
discussed here. 
In this section and elsewhere in this document procedures are out- 
lined for carrying out certain steps in the preparation of the fish for 
canning. It will be noted that these directions seldom are explicit. 
It is not practicable to make them so, as too many widely varying 
factors enter into the matter. The fish may be small or large, 
lean or fat, good or in poor condition, and fish falling into two or 
more of these classes may be mixed together, so that it does not 
pay to separate them. Many other factors also must be considered. 
The sauce for packing may be thick or watery; an important con- 
sideration is the sort of final product desired. One canner may 
desire the fish to be especially dry and firm and another may wish 
them otherwise. Knowledge gained from actual experience alone 
will teach how best to modify the method of preparation so as to 
obtain the desired result. 
EXPERIMENTAL RESULTS 
The first experimental packs were prepared for canning in the same 
way as fried fish, except that they were cooked in a boiling, 100 per 
cent saturated salt solution instead of in oil. Excellent results were 
obtained in this way. Experiments, however, to determine the best 
conditions for preparing the fish were not carried out at that time. 
Cooking in a strong salt solution brings about changes in the fish 
similar to those brought about by cooking in hot oil. The tempera- 
ture of boiling brine is abottt 227° (if saturated). This is almost as 
high as the average temperature of the oil used in many cases for 
frying. Fish, therefore, cook approximately as quickly as they do 
in the oil. Some fat is rendered and water and soluble extractives 
removed as in oil. In addition, the strong salt solution abstracts 
water by osmosis. 
The experiments showed that it is advisable to toughen the skins 
by drying the fish before cooking them in brine, as is done before 
frying fish in oil. 
The fish should not be brined, because salt diffuses into the tissues 
during cooking and some brine clings to the fish when they are 
removed from the cooking vat. The more concentracted the solution 
and the smaller the fish the more pronounced is the salting effect. 
Cooking in saturated brine salts pound-oval size fish about the right 
amount. Quarter-oil fish, however, have such a large surface, 
compared to their size, that they easily become too salty when cooked 
in strong brine. Lowering the concentration of the cooking solution 
prevent excessive saltness. Rinsing with fresh water does likewise. 
Both of these practices, however, are to be avoided. Lowering the 
concentration also lowers the boiling point of the solution, and the 
fish do not cook as quickly or lose water as readily as when high 
concentrations are used. Kinsed fish tend to stick to each other and 
to the wire baskets more than unrinsed ones. 
Tressler * showed that impurities, such as calcium and magnesium 
compounds in salt (sodium chloride), used for curing fish produced 

% Data on the experiments and packs produced are summarized in Table 29, p. 171. 
3% “Some Considerations Concerning the Salting of Fish.’ By Donald K. Tressler. Appendix V, 
Report U.S. Commissioner of Fisheries, 1919 (1921). Bureau of Fisheries Document No. 884, 55 pp., 
8 figs. Washington, 1920, 
