140 U. S. BUREAU OF FISHERIES 
TABLE 12.—Loss in weight of ‘‘quarter-oil”’ herring in air at different temperatures. 
Velocity 1,900 feet per minute 











; Time in minutes : Time in minutes 
Air tem- Air tem- 
Experiment No. perature, 7 Experiment No. perature, 
F. 15 20 ¥. 15 20 
iho Se Seat eee ee 22019 Fa eee = AZAON ELS (Dee: 3 22 Se eee 300 ZALS) | ees 
182b 250) |= hotels 20: 4a NS hen ee 325 30:08) ae 28223 
TPG. = ak TO a a es rai eee ee LES ESCA 17-0, 1] 0 ee a eee a 275 22:0.) soa 
12779 les ee Soe a 300) 222s 22 2456 ll\ DOG oe Re eee eye es 1356 25. Olea ee 
iy G2e' == eee 275 Osa: | EAs = eis 
|! 



1 Air velocity 800. 
Smoking.—Extensive smoking experiments were not carried out. 
Enough, however, were made to show that the method employed was 
entirely | practical. A good flavor and light brown color were given 
to small and medium-size quarter-oil fish simply by adding hard- 
wood smoke to the hot air used in cooking the fish. The high- 
velocity air brought about rapid smoking. Other conditions being 
equal, large fish will smoke more slowly than the smaller ones. 
In the experiments the concentration of the smoke was not as 
high as it should have been. The smoke generated was discarded 
after it had passed over the fish once. In a correctly designed 
plant most of the air that passes over the fish will be recirculated. 
This will quickly build up and maintain a heavy concentration of 
smoke, which will cure the fish rapidly. Nevertheless, the experi- 
ments made were quite successful. 
Sticking to the wire flakes and to each other—Maine herring did not 
tend to stick to the flakes and to each other to as great an extent as 
California pilchards did. Throughout the experiments the fish were 
spread upon the flakes, even for fancy packs, in the same general 
manner as they are spread by the flaking machine. Many of the 
fish, therefore, touched other fish. There was some marring and 
some breaking. It was no greater, however, than that obtamed with 
steamed fish. For “standard” goods and ordinary fancy packs no 
problem is presented. For very fancy goods it probably would pay 
to place the fish on the flakes, as now and then a tail will become 
glued to the skin of another fish and be broken off if they are 
scattered about. 
Toughening the skins of the fish prior to their being cooked had 
little, if any, beneficial effect as far as preventing sticking is concerned. 
Drippings from the fish—As with California pilchards, dripping 
occurred (although only to a small extent) with quarter-oil fish. 
It probably would have been advisable, however, had one flake been 
cooked over another to protect the lower flake with a drip pan. 
Cooling.—Most of the fish cooked were placed in the cooler and 
treated with outdoor air having a velocity of about 2,000 feet per 
minute and ranging in temperature from 65° to 70°. In all cases they 
cooled sufficiently to be handled for packing in 10 to 15 minutes. 

QUALITY OF PRODUCTS 
Fish prepared by the new process were better in appearance and 
taste both before and after canning than fish from the same lots pre- 
pared by the steaming process, Steaming removes much salt, oil, 
