Good to know. I also have a 5 gal bucket with Gamma Seal lid filled with brown sugar. In this case, no O2 packet because I use that bucket to re-fill my smaller pantry container when needed. That's only been in use for 2 months but it's still moist. But I'm trying to decide what to do with the 12 half gallon jars that I sealed with the O2 packs.

In the future I think I will store all my bulk brown sugar in a 5 gal bucket with sealed lid and no O2 pack. I was just trying to avoid that because opened bulk foods are not ideal IMO. My intention with the jars was that I would just be able to grab a new one from storage anytime my pantry canister ran low instead of refilling it from a bulk supply.

I package a lot of foods this way. For example, instead of bulk packaging oatmeal in a giant Mylar and 5 gal bucket, I package it in smaller 1.5 gallon zip top Mylar bags. When my pantry runs out, instead of refilling some container, I just go grab and new bag from storage. That way I never have to open a big bulk supply just to fill a small container. I only have smaller usable portions open at any one time, the rest stays sealed for long-term storage.