THE PRESERVATION OF FISH BY SMOKING AND DRYING 397 



Surprisingly enough it was not until the development in the last few years of 

 modern controlled smokehouses that any real advances have been made over 

 these primitive methods. In fact, in as progressive a country as the United States, 

 it is safe to say that the majority of its smoked fish products are still being pre- 

 pared by empirical methods. Except for the addition of roof and walls around 

 the fish and fires these processes do not show great improvement on those used 

 by the aborigine. 



About the time man was learning how to barbecue fish, or perhaps earlier, he 

 discovered the possibilities of drying fish in the open air. Like his modern counter- 

 part ancient man found that one of the hazards of open-air drying was the de- 

 velopment of maggots in his finished product. If the prevailing winds failed him 

 before his fish could dry and form a firm crust, the ever-present flies were ready 

 for action. Possibly by chance he discovered that a wood smudge burning under 

 his hanging fish not only eliminated the peril of fly-blowing, but imparted a 

 smoky flavor. 



With certain types of fish the smoke flavor was preferred; thus a smudge fire 

 under the drying fish became an essential part of the process. Use of proper wood, 

 regulation of the heat of the fire, and density of the smoke, together with a 

 preliminary salting or brining, completed the evolution of what is known as cold- 

 smoking. As in hot-smoking, the only appreciable advance modern man has made 

 over these primitive open-air smokeries is the addition of a roof and walls around 

 the fish and fire. Controlled processes based on scientific principles are just be- 

 ginning to come into use in fish smoking. 



In the United States production by this method of preservation has never 

 equaled in value or quantity that preserved by other methods, such as salting, 

 canning, and freezing. Figures for 1945 (Anon., 1945), as shown in Table 91 

 (p. 398), indicate a total output of smoked fishery products in the United States 

 and Alaska of almost 30 million pounds, valued at more than 8 million dollars. 



Principles of Smoke Curing 



The production of a so-called smoked fishery product actually involves far more 

 than the application of smoke. In general four interrelated processes are necessary: 

 (1) salting, (2) drying, (3) heat treatment, and (4) smoking (Shewan, 1945). 

 The quahty of the final product depends upon the proper care and control of each 

 of these processes. The final quality depends also upon the species of fish to be 

 smoked and the freshness of the original raw material. 



Salting. Salting the product prior to smoking is usually accomplished by soak- 

 ing the fish in a brine for a definite length of time. The strength of the brine used 

 will vary with the type of cure, and may vary with the species of fish and the 

 length of the salt cure. 



Brining aids in several ways. First of all it tends to firm the fish by removal of 

 moisture and by some denaturation of the proteins. In certain concentrations salt 

 tends to inhibit the growth of bacteria, and at times fish may be salted prior to 

 smoking and held in this condition until the smoking process is applied. Salt also 

 imparts a flavor to the product. In cures, such as used with herring and in the 

 mild-curing of salmon, the fish are held in a brine of a definite salt concentration 

 and at a suitable temperature so that the desirable "cured" flavor may be ob- 

 tained. The duration of the brining process and the concentration and purity of the 



