Let’s see…
A leafy aroma, reminiscent of forest breezes. The flavor starts slowly, mainly because it takes a minute to chew through the crunchy outer layer, before flowering into overwhelming bitterness, with strong notes of sawdust and tannin. A hint of weird mustiness and a certain je ne sais quoi … dead bugs, perhaps?
The finish is a lingering astringent taste. Very lingering - I’ve rinsed my mouth out twice and I can still taste it :P
Verdict: It’s actually worse than chewing raw acorns or oak leaves. Perhaps the galls concentrate the tannins as a defensive tactic?