Waring Corporation, Waring Ice Cream Parlor manual… (1970s)
“ The texture of the finished product depends largely on how fast it is processed. The slower the freezing process, the smoother the texture. You can easily control the processing rate, and hence the finished texture, by varying the amount of salt you use in the "freezing mixture." Using about three-fourths of a standard 26-ounce box of salt will result in a reasonably fast-acting freezing mixture, and produce a relatively smooth-textured finished product. Use of more salt, up to a full box, will shorten the processing time and produce a coarser, more granular, "icy" texture. ”
