Racked my chocolate stout into the secondary today and wanted to wash the yeast (White labs Irish Ale). Now, as I'm doing this I'm realizing that the sludge at the bottom is really dark and doesn't seem to want to clear up too much. Should I avoid washing yeast from a batch with such a dark beer? Will it impart a lot of flavors to the next batch I use it with?
If you wash it a few times you'll be fine, but don't take any chances, make sure it is clean before you pitch it. I re-used some choco stout yeast in a red ale and was lazy with the cleaning, the flavor came through noticeably... not bad but there.