That your powder has gone bad? I have a few canisters of opened powder that have been sitting in storage where the climate is not controlled for a year or so and I was wondering what the best way to tell if it's still ok to use. Thanks for the help!

If they were sealed, that would be good. I look for any yellowish tint and the bad ones small funny as compared to good/new ones.

Sealed and controlled they will last for YEARS.

Unsealed and uncontrolled they will still last for several years. I don't know that I have really had any the was BAD. I had some 12 yr of 4350 that smelled different than the new bottle. But I tested a couple of loads and my accurate load was still accurate and velocity was basically the same.

I'm sure powder does go bad I'm not sure I've had any and I doubt a year or so would be an issue.

I've seen some that looked like it had powdered red rust in it.

Pour it into an open container is you see red dust when pouring or left in the can the coating on the kernels has begun to oxidize, which means your can of whatever is no longer the powder it says it is and you are using it at your own risk.

1. A very acrid odor.( not solvent)
2. Powder has turned white or off-yellow
3.Kernels are out of shape
4.Powder looks like mush
Smokeless powder,if properly made, has no lifetime.
I have smokeless powder from 1914 that is still good ( Cordite) and use it all of the time.
I have several pounds of powder from the 1940's that is as good as new.
The only wartime powder I have ever seen that was "bad" was Italian WWII,slave labor made. It was from 7.35 Carcano ammo. Nasty,dangerous stuff.
I have also seen .50 BMG powder loaded in 1972 that would "smoke" if you opened the can. (Fumes)
The fumes corroded the projectile in the cases.
I reload several thousand rounds a month. I have never seen a bad modern powder in 45 years of reloading that was stored in a reasonable way. My shop goes from freezing to 100 degrees F over the year. No problems what so ever with the stored powders.

8 pounds of mil. surp 4895 was the only powder I've had that deteriorated. It was red brown in color and had a heavy nitric acid odor. From what I learned this deterioration was due to not having been rinsed properly during WWII.
In 57 years of reloading I have never seen any other powder go bad. roger

I've had exactly two cans of powder go bad. In both cases the powder turned rusty and dusty. Its probably just a fluke, but they were both 3031 in the old square can. Odd, since I use that one so seldom.

Thanks for all the help! It's still appears to be just fine. Going to load a few and punch some paper.

In over 50 years of reloading I had 1 1lb can go bad.. If I remember right it was some surplus 4831 who knows how old it was.

The can had rusted through the powder had a reddish color.

It became fertilizer.

A year or so is nothing; it will last for many decades. I have ww2 surplus powder that is still good. You can tell by the ether smell if good, and as stated above, it will have a red powder in it and won't smell like ether any more, if bad. I have never had any powder go bad but I bought a can of it once at a gun show from a widow. Black powder will last forever as it is not a chemical composition.