108 U. S. BUREAU OF FISHERIES 
qualities, but how to minimize the difficulties that had been met in 
preparing the fish for canning. The general results of these experi- 
ments are discussed here.* 
EXPERIMENTAL RESULTS 
Brining.—During cooking much steam condenses on the fish and 
some juices run from them. These liquids remove salt, necessitating 
heavy brining if the cooked fish are to retain enough salt to flavor 
them. The heavy brining also helped a little in toughening the skins 
of the fish. Other than this, it had no pronounced effect upon the 
manner in which the fish withstood steaming. 
Drying.—I\t is advisable to toughen the skins by drying before 
steaming the fish. In the experiments this helped considerably in 
preventing breakage, both during steaming and later when the fish 
were packed. Drying also removes some water, and this aids in 
getting the fish in good condition for canning. 
Cooked fish lose considerable water when they stand on flakes 
exposed to the air for several hours. Ten lots of various-sized 
steamed fish, some partially dried after steaming, lost, when allowed 
to stand overnight on different nights, from 7.1 to 14.2 (average 
10.9) per cent of their original weight before being steamed. Under 
similar conditions 16 lots of fish that had been cooked in a current of 
hot air averaged 6 per cent loss in weight. 
Most people connected with sardine canning believe that partially 
dried fish absorb water when exposed to air containing much mois- 
ture, as on a rainy day. Weber makes this mistake. On page 58 
of his paper (see footnote, p. 72) he writes of dried fish, particularly 
on rainy days, absorbing enough water to make their handling 
dificult. The only way “partially dried, steamed fish can become 
moist from water in the air is for vapor to condense upon them. 
This can not take place unless the temperature of the fish is below 
the air temperature, and this seldom happens in sardine-canning 
practice. What really takes place is this: The surface of fish com- 
ing from the drier is dry to the touch and remains so as long as water 
is removed from the surface faster than it diffuses from within. 
When the relative humidity of the air is high, as on a rainy day, a 
condition is soon reached in which water diffuses to the surface more 
rapidly than it is removed. The fish then appears as if it had taken 
up water from the air. Even under such adverse conditions the fish 
continues to lose some water upon standing. 
Some experiments were carried out on the drying of steamed fish 
of sizes suitable for the half-oil and quarter-oil packs. Complete 
data are given in Table 31, page 180. The drying of steamed fish is 
discussed in detail elsewhere (pp. 121 to 129). 
Steaming.—Cooking with steam removes some water from the 
fish. Even when “wet” steam at 212° and atmospheric pressure 
were used there was some loss in weight. With ‘‘wet”’ steam under 
pressure the loss was greater and in a current of superheated steam 
still greater. In ‘“‘wet’’ steam the loss in weight comes from the 
cooking effect, which renders some oil, destroys the cellular structure, 
and thus causes juices to drain from the fish. Superheated steam 


87 Details are given in Table 30, p. 175. 

