title_body: Blond flakes in espresso grounds
upvoted_answer: I think you're talking about coffee bean chaff, it's pictured after roasting in this blog. These are blonde flakes the come off the beans during the roasting process. In most commercially sold coffee I've seen, the chaff has been removed. When I roasted my own coffee I didn't bother because it's not so easy to separate them from the beans and they are harmless (at least for brewing).
  In your case, it seems some of the chaff was still stuck on the beans after roasting, but it came off when grinding the beans. I wouldn't worry about it too much for brewing coffee, but if you want to use the ground beans in another dish, it might be better to use a sieve to strain the chaff.