How much airspace in the plastic tester bottle?

[Ike]

OK... I'm obviously doing it wrong.

I'm on my third iteration of using a plastic tester bottle to confirm depth of bottle carbonation in backsweetened ciders/rootbeers and keep having the same problem: the tester bottle is HOLY CRAP hard to touch but when I crack a glass bottle to test: it's as flat as a board.

SO, I think the issue I have is the amount of headspace I'm leaving in the plastic bottles. How much is right? Since my last batch I seem to recall someone saying "70-80%" full in a post, but can't recall where I saw that. I only left about 1.5 inches in a 20oz bottle, so if that's the case then I can see why my bottle would be feeling tighter than one only filled 3/4 full.

So, what gives?

Ike

 

[MaxStout]

Bad caps on the glass bottles? Otherwise, I can't see how there would be such a disparity between the two types, just on headspace alone.

 

[z-bob]

My 1L plastic pop bottles carb faster than glass bottles; I don't really know why. (I leave about 1 inch of headspace) Have you opened one of the plastics?

 

[Ike]

My 1L plastic pop bottles carb faster than glass bottles; I don't really know why. (I leave about 1 inch of headspace) Have you opened one of the plastics?

Yes, on previous batches. Not so far on this most recent batch.

In the past, by the time I gave up on them and opened them, the plastic ones were bottle bombs: they were definitely carbing up like a champ.

ALSO, your suggestion that they carb up faster for some reason MAY be why others suggest to only partially fill the bottle. The larger head space would allow the bottle to harden slower.

 

[Ike]

Bad caps on the glass bottles? Otherwise, I can't see how there would be such a disparity between the two types, just on headspace alone.

In past batches, I've written it off to an infected plastic bottle or sluggish yeast. Now, I'm starting to see a trend. The caps seem to be doing well, over all my other brews.


So far, I've only opened one on this most recent batch, two days ago. When I opened it I got an anemic but definitely present hiss. A hard pour into the glass yielded no head, but both my wife and I detected that effervescent tingle on the tongue. SO, something is happening, it's just happening a lot slower than it is happening in plastic.

Ike

 

[MaxStout]

Are you adding the priming sugar to the whole batch before bottling, or dosing each bottle individually? If the latter, maybe there's inconsistencies in the amount of sugar bottle to bottle.

 

[Ike]

Are you adding the priming sugar to the whole batch before bottling, or dosing each bottle individually? If the latter, maybe there's inconsistencies in the amount of sugar bottle to bottle.

Priming the whole batch with the transfer into the bottling bucket. I tried carb tabs once and hated the results; I've always kept the idea of using corn/table sugar in each bottle but have never tried it.

Ike