What's wrong with my paint?

Bought different glosses of BM paint, eggshell, pearl, & semi-gloss. Have made some touch ups during my punch list. Every time I open the semi-gloss paint, it sounds like I'm opening a pop can. Paint appears to be ok, but is there any reason why it should sound under pressure?

If you live at a high altitude and the paint was sealed by manufacture at an low altitude this can happen. I had this happen when I lived at 10,000 feet for many years. Some cans of coffee were very noisy when opened. Due to atmospheric pressure change. WW

WW wrote the following on 12/7/2012 10:17 AM (ET):

Coffee cans are filled under vacuum. The noise you hear is air going in, not coming out.

The only thing I can think of is that some of the air in the can has been used up and you hear air filling that partial vacuum when you open the can. I've had that happen on oil base paints after they have sat a while and formed a thick skin.

Have you used more of the semi-gloss? That is, is there less in the can?

Exactly! Not much of the semi-gloss left.

It's latex btw.

I've had potato chip bags explode in the MH due to altitude changes.

Steve

Oxygen plays a part in the way oil based coatings cure, but not in latex paints. The only oxygen to dissolve in wet latex paint would be whatever oxygen goes into solution in the water the paint is thinned with, and that's not gonna change while the can is in storage.

So, there is no good reason I can think of for the semigloss paint to be under any kind of pressure. And, to be honest, I've never experienced that with any kind of paint can I've opened; oil or latex, glossy or flat.

I suspect it's just the can you're using. Home Depot sells empty paint cans. I suspect that if you transfer your semi-gloss paint to another can, the problem will disappear.