Leftover yeast into Bread Starter

I know this sounds crazy, but has anyone made bread from the left over yeast from the primary fermenter? I am an avid bread baker and after racking a pils from the primary to the secondary, I looked at all that yeast in the bottom of the fermenter and thought "bread starter."

I have mixed a tablespoon of it with 1 cup of water and 3/4 cup of flour and it's bubbling away on my counter.

I was wondering if it's safe to consume since there is probably spent grains and hops mixed in with it.

Thanks

That's not crazy at all! There was a thread on this topic not too long ago. I'll try and search for it and get back to you.

I'll make pizza dough quite frequently with yeast from the primary...

Yeah, I've done this a few times, and it works fine. In my limited experience the dough seems to take longer to rise than when I've used bakers' yeast or sourdough, but that might just be my own post-brewing impatience.