I found two 1 pound containers of Titegroup that I forgot I had stashed in my reloading room. One container has never been opened, the other has been opened and about .25 pounds have been used. Handwritten purchase date on the container shows this to have been purchased about 4 years ago. Does anybody see any reason why I can't use this powder?
Going to be on my soapbox for a bit. The shooting community has been lacking adult supervisor for so long on gunpowder, that certain myths have developed and one of them is that powder will not go bad if the seal is unbroken. I think that comes from the warning to keep bottles sealed.
Air is full of water, it is called humidity. Water is a polar covalent molecule and the "ionic" end attacks the double bonds on nitrocellulose. All ionic compounds attack those double bonds, like rust in those old powder cans. But, and this is a big but, gunpowder is still deteriorating whether or not you break the seal.
So, break the seals, break them regularly, and take a sniff of your powder stocks.
remove from the house, and pour all powder out that smells vinegary/bitter. I believe the bitterness in what I smelt was nitric acid gas, in small concentrations. When gunpowder breaks down it releases NOx and I don't know what each molecule smells like, but I doubt any of them smell good.
This is gunpowder at a very dangerous condition.
That red is either nitric acid gas, or nitrogen dioxide, which will become nitric acid gas when it encounters a water molecule. Gunpowder that deteriorated is ready to autocombust and burn your house down. No joke! Old gunpowder is dangerous as all heck, and if you ever google ammunition dump explosions, (which happen about once a month) the primary reason for the big kabooms, is the autocombustion of old gunpowders.
If you ever smell that red vapor you won't forget it. It will knock your socks off, it is horrible.
So, if your powder smells fine, go shoot it. A good rule of thumb is use it up before it is ten years old. When powder is 20 years old it really starts to fail. But sometimes sooner.
I write on my bottles the lot date, or the purchase date, if I can't figure out when it was made. And I keep my eyes on the old stock and use that up first.
So, to repeat, inspect your powder frequently, break the seal and sniff. If it smells bad, get rid of it before it burns your house down.