My wife bought espresso beans for baking chocolate muffins (Unicorn Blood, chosen because of the cute label), so we ended up with most of a bag to be used for drip.

When I grind the beans, there are blond flakes in the grind, as if someone dusted the grounds and kitchen counter with the remains at the bottom of a Corn Flakes box. The whole beans look uniformly dark.

What causes the blond highlights in the grounds? Are they associated with a different taste or condition of the beans? (The coffee I've made with the beans tastes dark, a bit malty or woody, like chicory, but not bitter.)

2 Answers 2


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.

  • 1
    Thanks @JJJ, the color is like chaff from the picture. I don't see any chaff on the bean before I grind it. Maybe there are bits of chaff hiding in the bean cleavage that I've overlooked.
    – jlb
    Commented Oct 28, 2020 at 17:38
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    @jlb yea, I think some tend to get trapped there. If you take just one bean and split it (push your nail in) then you might find it too. I haven't noticed one in my espresso grind, but I think I can see them too if I'd grind a bit coarser for, say, a French press, even with store-bought beans where you don't see any chaff in the bag.
    – JJJ
    Commented Oct 28, 2020 at 17:56

I roast with a Fresh Roast SR540 and most of the chaff comes off, but I have noticed that when I grind (for drip) there are light colored flakes as you have described. That is chaff that has stuck to the center cut of the bean. I, like you, was wondering what it was until I roasted some Kenya AA. The photo below compares the Kenya AA (top) Full City with some Ethiopian City. You can clearly see the chaff remnants on the KAA, but not so much on the Ethiopian. After grinding either, one can clearly see the chaff.

Maybe I'll try using the Fresh Roast (on cool) to try to clean the beans, but that might be more harm than good (fresh oxygen exposure?). enter image description here

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