The first skinless hot dog casings were sold under the brand name Nojax. The name was a shortened form of “no jackets,” referring to the fact that the casing jacket was removed from the cooked sausage before it reached consumers.
Nojax casings were developed by Erwin O. Freund’s new company in Chicago after his 1925 cellulose-casing innovation. The casing acted as a temporary cooking mold: it held the finely mixed meat in shape, allowed the sausage to be processed, and was then stripped away. This made it possible to sell a frankfurter with a smooth surface but no edible outer skin.
The product was initially sold to local Chicago sausage makers, helping establish the production method that became standard for many American hot dogs. The name Nojax was a trade name, not a description of a different sausage recipe.
“Skinless” can be misleading. These hot dogs were not cooked loose in a vat; they were formed and cooked inside a cellulose casing. The difference is that the casing was inedible and removed before sale, unlike a natural sheep casing that remains around the sausage.