To the OP for future reference - I always bottled one “sacrificial” plastic bottle to simply observe how well the carbonation was progressing. The plastic bottle would be squeezed a bit to have the liquid completely fill the collapsed bottle space, which would then create headspace and a stiffness to the plastic as the CO2 was created in the carbonation process. That way I knew where the carbonation level was at for all of the other glass bottles.
I’ve done this once. Not for the logical reason you are explaining but out of desperation on bottling day. So much pressure built up that the cap blew 20 feet in the air when I opened it. Be careful, a silly way to lose an eye!
Carbonation has never been an issue before, this is the first batch that does.
I use 2 domino sugar cubes (1/2 teaspoons each) for a 22 oz glass bottle.
Carbonation is either right on, or a tad too much. I dislike plastic/pet bottles,
discarded them a while ago.
Variables
First batch using lager W-34/70 yeast
First time using yeast so close to expiration (4 months to go)
First under pitch (slightly) by manufacturers recommendations
I am assuming you brewed a lager style beer? If you went through the lager phase at 34-35F a lot of your yeast dropped out. I think Denny‘s comment is correct is that if you shake what yeast is left in the bottle up and let it warm up it will carbonate as much as it can I don’t think you’re going to get an ideally carbonated product but close.
In the past bottle conditioning this style of beer brewers would add a little bit of yeast back to the product after the lager phase and then package.
Page 177 in Palmer’s book provides instruction
Used W-34/70 as if it were an ale yeast, didn’t do a lager phase.
3 weeks ferment, 2 weeks bottle condition/carb @ 73 degrees, stored at 60 degrees unit placed in fridge is my standard protocol.
When bottles where flipped upside down twice, there was sediment on the bottom swirling about.
Haven’t seen this before in any other ale all-grain batches.
Attempted the short/easy/lazy mans way of doing a lager.