Plastic will let in oxygen. You would need to use a Mylar bag laminated to aluminum to get the gas and moisture resistance needed for long-term storage.
This is the method I prefer now, although I still have beans, cornstarch baking soda, etch, stored in glass jars. But they are heavy to transport and breakable, so I’ve decided I like storing dry goods in Mylar with oxygen absorbers and save the jars for canning meats and such.
Speaking of oxygen absorbers, I’d skip vacuum packing over an oxygen absorber any day. Vacuum packing will not remove all the oxygen and throwing in an oxygen absorber couldn’t be any easier.
This is near the top of my list—how to minimize the use of O2 absorbers with repeated access to buckets of food items.
I know what is needed, but have yet to find it. It is a combination of both the absorber AND pulling air from the container before sealing the lid. The solution is a simple vacuum pull on a zip-lockable plastic bag, the bag big enough to insert the bucket in side.
The process is to remove the food item (e.g., scoop of beans) from the bucket, insert the bucket and lid in a suitable plastic bag (that can be sucked down), replace the expended absorber in the bucket with a new absorber, set the lid loosely on the bucket, close the bag, suck it down, from the outside of the bag press or close the lid on the bucket, inflate the bag, and remove the now capped bucket with new absorber inside. Waalaa.
But I cannot find the bag and vacuum big enough to do this.