Why and how fast does rice get rancid?

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Joined Sep 5, 2008
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.
 
Last edited:

phatch

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Metals promote rancidity in many cases. Cast iron accelerates rancidity in the oil coating it and it wouldn't surprise me for aluminum to do so.
 
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Could be bacillus spores- Spores are bacteria's way of surviving harsh environmental conditions. They stay dormant when they couldn't survive, then spawn when environmental conditions are right, presence of oxygen, lower isotonic solution etc.

Not familiar with the canning process of aged rice, rancidity if I'm not mistaken is the result of oxidation of oils.

Is the can aluminum or tin? Aluminum is far less reactive than tin. Put a magnet on it, if it sticks it's not aluminum.
 
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It might be because of the fact that it IS organic and the bran is still in the kernel. It has a finite shelf life.
 
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I live a good distance from grocery stores, but I know that brown rice, has a limited shelf life.  In order to have a good supply on hand,  I do it up in food saver bags and store it in the freezer.  I also store other dry goods such as flour, in the freezer.  If something comes packaged in tin,  I transfer it to some other container such as glass or plastic with a screw lid.  This was something I inherited from MOM,  but never knew why she did it. 
 
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Thanks guys. A magnet approached to the can immediately sticks to it, so ... that means it's tin then?
 

The rice is not brown rice, it's white rice, but it's organic, I'm not sure exactly how much of the outer shell remains on the grain, but it's whiter than Uncle Bens (which has some of the outer shell I believe?).

Anyway, next time I'll transfer the rice to a glass jar and keep it in the fridge.
 

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