A bit of more careful analysis.
Refer to this post that explains the need for initial burping on the Grove Bag: First grow after a 40 yr break, 1 plant, DWC, LED 450W - #163 by MrWizard
After burping to get the humidity back in range I left them alone for 30 days.
Cure 1 = Grove Bags
Cure 2 = Canning Jar
The first red line is where I opened the Grove bag for the 1st time and removed some bud, then resealed.
The 2nd red line is where I open the Canning Jar and removed a bud.
Notice that throughout the 30 days the Grove bag held the humidity very stable, where the humidity in the jar slowly crept up from 64.2% to 66.3%. After pulling the bud, the humidity in jar dropped back down and slowly rose, like you would expect from a burp. Also worth noting, there was only about 15g of bud in the jar, where there was about 70g in the Grove Bag. So I would have expected a lot more available moisture in the Grove Bag.
The bags definitely regulate moisture judging by this. Next time I will do this same test between a jar and the bags using the same weight of bud. Having such different amounts of available moisture I think skewed the results. Had the weights been the same I suspect the delta would have been even more extreme. In fact I bet I would have had no choice but to burp the jar more frequently.
