I dry mine out in the microwave by doing 20 second intervals on high and stirring between each. About 2 minutes is all it takes then I overfill the whole tray and level them off with my hand, slightly tamping them below the dividers so the flame doesn't jump rows. Works every time.
When I dry them in the microwave oven, I do the same thing. I go for 30 seconds max, take them out and stir, then go for another 30 seconds. I can feel and see the moisture coming out of them as I stir them each time, and once I stop feeling/seeing the steam coming out of them, I know they're ready to go.
Alternately, I put a bunch of them in a thin layer in a large pan and cook them in a convection oven for a few hours at 225° to 275°F. Then I put them in a jar with a good seal and they stay very dry until the next time I need some.
I've found that the pellets absorb moisture if they're just stored in the baggies in which they arrive. For them to burn well at my elevation, in the
AMNPS, I need them to be bone dry and have everything else just right. Technically, the elevation here is too high. But with improved airflow (which I now have due to some modifications to the MES), getting and keeping the pellets very dry, and making sure they're lit well at the start, I've been having 100% success with them.
Something people need to realize is that thin polyethylene (as in ziplock bags) is not moisture proof. It's waterproof, but doesn't stop the individual water molecules of water vapor. This is also true for a lot of flavor compounds. Just put a sliced onion in a ziplock bag and then smell it. You can smell it easily through the walls of the baggie. So many molecules are able to go through a thin layer of polyethylene. Thicker layers may block moisture, but thin layers really don't.
It's kind of like Gore-Tex. It stops liquid water, but allows water vapor to pass. It's not as porous as Gore-Tex, but you get the idea.
So the point is, that to keep something dry, you can't just use a baggie for long-term storage. This is also the reason that the vacuum-sealing bags are made of a multi-layer arrangement. We hope the vacuum bags do a better job of blocking water vapor and flavor molecules. They'd probably work OK for storing dried pellets, too. But I just use old pickle jars with the rubber seals in their lids or mason jars, etc. Thick plastic jugs can work well, too. Just not thin ziplock bags.
Further, when the pellets are shipped in a thin bag, small holes likely get punched in the baggie as they're jostled around. So even if the baggies did block water vapor, you'd still need to dry them to get them to work at this elevation. Folks who live at lower elevations have enough oxygen in their air that small concentrations of moisture in the wood probably don't affect the burning very much. But up here, you really need every advantage you can get!
I've been using a small computer fan, held in my hand, to blow on the pellets when lighting them. That steady air blowing gets them going so well that they burst into flames and I have a hard time getting them to go out again (going back to just the smoldering mode). I have to close the door on the smoker and let the flame deplete the oxygen somewhat, and then I can open it and quickly blow out the flames. After that, they're really glowing well, and I've had no problems, even with some recent cold smoking where there's not much draft through the MES.
I often forget to mention that when I'm helping somebody with their
AMNPS, but You're right----I try to keep my pellets 1/4" to 3/8" from the top, and I usually tap the whole tray to get them to settle in more tightly. At that height, it won't jump rows, but will keep burning, if everything else is done properly.
Bear
Up here, I need to go even higher. I let them sit at least level, and often humped up slightly above the top of the
AMNPS, but I just clear a little path at the peaks of the separators so they can't quite touch to prevent short-circuiting of the fire. There's not much chance of the cherry jumping even a tiny gap at this elevation.
At a lower elevation, I might be having short-circuiting, but up here, doing it this way works great.
So maybe people who are having problems need to go higher, and those who are getting good burning can go with (or even require) a lower fill.