I rinse mine after I cook them. Why? Because I prefer to eat them in savory dishes, like one would eat rice. (i.e. With beans, as a bed for fish or chinese dishes, etc.)
I, too, have wondered if any of the fiber is being rinsed away.
If i rinse my steel cut oats after i cook them am i rinsing away all the soluble fiber?
Why would you rinse them? I cook them in the crock overnight and quite simply, and just add a bit of creme fresh and honey. Some people toast them in the oven or in a skillet, as did my mother, but I don't care for them that way. I put water a pinch of sea salt and 1 cup of SCO's in the crock and set to low. I use about 3 to 4 cups of water, just depends on how I want them, loose or thick. You can let them just sit in the crock til morning and cook on high for an hour if you're afraid of sleeping with them cooking, and to be honest the smell tends to wake you.