Nothing improves the flavor of a sausage in a such a rapid and inexpensive way as submitting it to a smoking process. In countries such as Poland and Germany smoked meats account for 60% of all ready to eat meat products. In the USA the variety of sausages carried in supermarkets pale in comparison with their European counterparts. Statistically, smoked sausages control a large share of the American market but most of the credit goes to emulsified and lightly smoked sausages such as hotdogs, frankfurters or bolognas. Today, the manufacture of smoked sausages conforms to different criteria and smoke is added purely for the love of the flavor. Many products are not smoked with hardwood at all but receive liquid smoke instead. This is accomplished by adding liquid smoke during mixing or showering sausages with a liquid smoke spray. As the synthetic casings can be ordered in mahogany color, to the untrained person such a liquid smoke enriched sausage can easily pass as the original.
In the past sausages were smoked for different reasons. Our ancestors did not care much about the flavor of the meat or the sausage. What they needed was a method that would preserve food for later use. They tried different ways to preserve meat and this eventually lead to methods like salt curing, drying, smoking and fermenting. It was discovered that salted meats could be air dried and would keep for a long time. Soon two different methods of drying developed. In Northern European countries, winters were cold and the only way meat could be dried at low temperatures was placing them close to the fire. Originally that took place in caves where fire was the center of all social activities, then separate enclosures (smokehouses) were built for drying and storing meats. As the temperature had to be higher than freezing temperatures outside, the fire was slowly burning on the ground providing suitable temperatures for drying. It is common knowledge that fire produces smoke and the meats and sausages were dried and smoked at the same time. They were just flavored with cold smoke for long time which not only further preserved the product but gave it a wonderful aroma. In addition it prevented molds from growing on the surface. Those advantages of applying smoke were not ignored by our ancestors and smoking became the art in itself. This does not deny the fact that the main method was drying and the benefits of smoke was just an added bonus.
This can be easily observed by studying drying methods in Southern Europe. The moderate climate was less humid, the slightly blowing winds were ever present and meats were easily dried in the open air for most of the year. There was hardly any need for burning fires and hams and sausages were produced by drying. Spanish chorizos or Italian salamis were made by drying and meat smoking never became so popular as in the North.
For more information, see the smoked sausage type.