What does it mean when chia seeds are bitter?
This might be the reason that last bunch were nasty bitter: they can go rancid. I smelled them: OFF! http://www.chiaseedspot.com/do-chia-seeds-go-rancid/

I purchased from bulk and consumed just now.  Yuck!!! I've NEVER had chia with any bitter chemical taste before, and now I must discard a big bag of it bought at a Smart &amp; Final' Superstore's bulk section, on sale at a good price, but sold at 1/2 the normal price because  being so substandard in truth. Wish I had tasted it first, because I didn't save the receipt. :(