I understand that fat gets rancid, so brown rice has more of a chance to get rancid, because (I believe) the outer shell is richer in lipid. For that reason I keep all my brown rices in the fridge.
However I recently got a tin of Acquarello Organic Carnarolli aged rice, opened it about 6 months ago and used some of it, left the rest in the (aluminum?) tin with a plastic cover in a dark closet.
The other night as I opened it, I immediately detected a strong rancid smell. What a bummer. I made the risotto with plain old arborio rice instead.
So what made my Carnarolli rice become rancid so fast? I can keep rice in carboard boxes or plastic bags or glass jars for more than year without having that problem, so I'm wondering if it's the tin? Is that a bad idea to keep rice in an aluminum tin? If yes why would they ship it like that?
It's a horrible feeling throwing out a $20 can of rice.