I've been using Ischia successfully for about 16 months now and Camaldoli for about 4 months. When I need to feed them, I use 1:1:1 ratio starter:water:AP flour. Lately I've noticed that when I add the starter to the water in my formula and whisk it, the entire starter does not dissolve into the water. Instead, there's this boogery (technical term?) residue that remains on the whisk. It doesn't seem to affect the performance of my dough but wondered if anyone knows what it is?