Lutefisk came up during the podcast and people asked how soaking fish in lye would be a good idea.
The history of lutefisk as I heard it. Fishing villages in Norway typically caught fish during the summer months and dried the fish on racks for winter food. One of these villages was raided near the end of the fishing season, and a portion of the village was burned. The racks of drying fish were toppled into the ashes. As you mentioned in the podcast, lye is produced from ash. When the survivors returned, they saved as much of the fish as they could, but a lot of it was soaked in the lye from the ashes. They lived on this lye soaked fish that year and commemorated surviving that winter by making the fish in later years.