Old (expired) nuts

Disclaimer: No pun or insult was intended by the subject title ...

What is it about old peanuts, walnuts and perhaps others, that makes them taste like - gasp - kerosene? Has anyone here experienced this? Sometimes when nuts have been laying around too long, they literally become inedible. I'm assuming that something happens to their natural oils, that they break down somewhat. In any case, stale nuts sure can be foul - I recently bit into a granola bar that seems to have gone that way and it was most distasteful.

Any chemists among us?

They go rancid because the oils aren't stable. From our friends at Cornell.

Thanks Howie!

I keep nuts for baking etc in the freezer to combat the rancidity factor.

I keep nuts for baking etc in the freezer to combat the rancidity factor.

We do the same. One of the reasons we need a bigger freezer.


Mike

My wife Beverly has an aunt in Americus, GA. Once visiting her several years ago she just about filled our van with pecans. Upon return home we divided them into one pound packages and froze them. After about five years, those still in there got so hard, you could not cut them with a knife; yes, after thawing.

And rancid oils have reactive radicals that attack healthy cells.