Freshly harvested and dried dulse is too tough for most people to chew. The secret of tender dulse is a bit like aging cheese. The dulse is spread out in the early morning hours to soak up a bit of humidity from the air, and then it is packed away tightly for a few weeks. This kicks off an enzyme process that breaks down the cell walls of the dulse, and the flavors slowly change.
Once dulse has been softened, it needs to be used within six months, unless it is kept refrigerated, in which case it can be kept for a year. Most people eat soft dulse as is.