The traditional method involves wringing the potato water from the grated potatoes into a bowl, waiting about 30 minutes to allow the starch to settle at the bottom of the liquid, pouring off the liquid and saving the starch to mix back into the boxty batter (the starch acts as a binder and helps make the boxty crispier). Many Irish chefs still do this and others don't. You can decide which end result you prefer. If you skip this step you may need to cut back a little on the buttermilk.