Who invented the 1925 process used for skinless hot dog casings?

Erwin O. Freund invented the 1925 process used to make skinless hot dog casings. In Chicago, Freund was developing cellulose casings as a practical substitute for animal-intestine casings. The cellulose tube could be stuffed, linked, smoked, and cooked like a traditional casing.

The key discovery was that the casing could be removed after cooking while the sausage retained its shape. That accidental observation created the modern “skinless” frankfurter: the sausage is cooked inside a casing, but the casing is peeled away before packaging rather than eaten by the customer.

Freund founded the company that became Visking, later Viskase, and the innovation helped standardize mass-produced hot dogs. The process did not mean that skinless hot dogs were made without any casing at all; they still required a temporary cellulose casing during manufacture.

A common mix-up is to credit famous hot-dog sellers such as Charles Feltman, Oscar Mayer, or Nathan Handwerker. Those figures are associated with selling, branding, or popularizing hot dogs—not with inventing the 1925 skinless-casing process.