Bags that actually keep tobacco fresh for a while?

So I've got my car kit that I take with me when I run errands, etc...

I keep my baccy in a little "snack size" ziploc. I always put the baccy I don't use back in the mason jar when I get back home. Well this time, I forgot my baggie of pipe tobacco in my pouch, it was only in the bag for about 24 hours and it was so dry it disintegrated upon touching it. Does anyone know of a baggy I can use to throw in my "travel for the day" pipe pouch that won't dry up for a few days to a week? It's kind of a drag, and a waste of bags to have to remember to re-jar the tobacco I don't use.

I don't want anything hard sided because it all goes in a nice waxed canvas rollup that I have for my pipe/accessories, etc..

Thanks!