Sausage making originally developed as a means to preserve and transport meat. Primitive societies learned that dried berries and spices could be added to dried meat. By 600-500 BC we have mention of sausages from China, Rome and Greece. Sausages come in two main types: fresh and cured. Cured sausages are subdivided into cooked and dried. Most cured sausages are smoked however this is not mandatory. The curing process itself changes the meat and imparts its own familiar flavors. An example is the difference in taste between a pork roast and a ham.

All smoked sausages are cured. The reason for this is the threat of botulism. The bacterium responsible, Clostridium botulinum, is ubiquitous in the environment, grows in the anaerobic conditions created in the smoke house and thrives in the 40 °F to 140 °F (5 °C to 60 °C) temperature range. Thus, for safety reasons, the sausages are cured before smoking.

[21] Wurst (Kochwurst)

Both nitrites and nitrates are used in curing meats and making sausages. Nitrites are used for all types of sausages and are the most common. Nitrates are used only in the preparation of the cured dry style of sausages. Over a period of time the nitrates are converted into nitrites. Nitrites themselves are very common in our food supply and for instance are found at levels up to 3,000 ppm by weight (w/w) in foods like beets, lettuce, potatoes, and radishes.

The human digestive system manufactures nitrites and this is likely what prevents botulism which would thrive in the anaerobic conditions and temperature range of the digestive system (gut). Cured meat products typically contain less than 40 ppm w/w nitrites.

Potassium nitrite and potassium nitrate allow sausages with lower levels of sodium. When using the potassium form, it is necessary to include other ingredients to mask the more bitter flavours imparted. Sodium and potassium nitrite are quite toxic to humans with the lethal dose being about 4 grams. As little as 22 mg/kg of body weight can cause death. This is about 2.2 grams for a body mass of 100 kg. Thus, there is enough sodium nitrite in 2 ounces of Prague powder #1 to kill a person.

 

[22] Wurst (Rohwurst)

These are simply seasoned ground meats that are cooked before serving. Fresh sausages normally do not use cure (Prague powder #1) although cure can be used if desired. In addition fresh sausages typically do not use smoke flavors, although liquid smoke can be used. Fresh sausages are never smoked in a smoker because of the danger of botulism.

The primary seasoning agent in fresh sausages is salt and sugar along with various savory herbs and spices and often vegetables including onion and garlic.

A British Fresh sausage typically contains around 10% Butcher's Rusk, 10% Water, 2.5% Seasoning, and 77.5% meat.[1] At point of sale British sausages will often be labelled as "actual meat content X%". As meat can be fatty or lean the X% is calculated using reference tables with the intention being to give a fairer representation of the "visual lean" meat content.
 

[20] Wurst (Bruehwurst)

Cured sausages differ from fresh sausages by including 2 teaspoons of cure (Prague powder #1) per 10 pounds of finished product. This is usually interpreted per 10 pounds of meat. This works out to 4 ounces of cure for 100 pounds of sausage.

Next the product is typically hot smoked. However similar effects can be achieved by incorporating liquid smoke in the recipe. Smoking temperatures vary and are typically less than 155 degrees Fahrenheit (68 °C). At a temperature of 152 °F (67 °C) these sausages are fully cooked.

In some cases a cold smoke is used. If so - then the sausage may be cooked in a water bath held at the proper temperature. An example of this process is the preparation of Braunschweiger. In this style of sausage, after stuffing into 2.75 inch to 3 inch hog buns or fiberous casings, the sausage is submerged in 160 °F (70 °C) water for 2 to 2½ hours until the internal temperature reaches 152 °F (67 °C). At this point the sausage should be chilled in ice water, then cold smoked at a temperature of 115 to 120 °F (46 to 49 °C) for 2-3 hours.

Cured dry sausages are prepared in a similar fashion to cured cooked sausages. The major difference is that Prague powder #2 will be used in place of Prague powder #1. In addition certified meats must be used. Since these products are never heated to a temperature that can kill trichinosis it is necessary to accomplish this by other methods. The usual method is via freezing. Pork may be rendered acceptable for use in dry sausages by freezing it using the following guidelines: 5 °F 20-30 days /  -10 °F 10-20 days / -20 °F     6-12 days.

The specific regulations are quite complex and are beyond the scope of this article. They depend on the thickness of the cuts of meat, the packaging method, and other factors. In addition there are very specific requirements as to the times in the drying rooms and the temperatures in the smoke rooms.

While it is quite feasible for the small sausage kitchen or hobbyist to produce excellent cured dry sausages, a great deal of technical information is required. Alternatively certified pork can be simply purchased.

This article uses material from the Wikipedia  article " Sausage making" and is licensed under the GNU Free Documentation License.