Pet Bottles Not Holding A Seal

[mossyrocks]

2 of my last couple of brews have been bottled in PET bottles. Usually I use 500ml glass bottles.

I have noticed (or should I say wasted) several bottles, after a week or 2, are quite easy to squeeze.
When I do squeeze them I can hear air being sucked in and out.
As a result I have found the beer in the bottles to be flat.

All bottles are capped the same way (with the white caps) and I ensure the caps are on as tight as I can screw them.

Is this an example of older PET bottles becoming more pourous?

 

[Stuster]

If there's air being sucked in and out when you squeeze them, it sounds like the caps aren't fitting right. Might the caps not be the correct thread for the tops? It doesn't sound like the bottles are porous though, because you wouldn't be able to hear air moving through tiny holes in the bottle. :huh:

 

[wyatt_girth]

At the moment, all I use is PET bottles. I have not had any problems as yet. While they are not very old - 6 months - some I have used maybe 3 times with the same lids. I originally bought these as a short term thing but the easiness for capping etc has made me continue with them. I usually give them a slight squeeze as I put the lids on so that I can tell how far along they are in carbonating, by how firm they have become.
Maybe just some new caps will solve your problem. I would have thought that one cap would fit all but, as stuster said, you may need to make sure you get the right ones for your bottles.

 

[mossyrocks]

At the moment, all I use is PET bottles. I have not had any problems as yet. While they are not very old - 6 months - some I have used maybe 3 times with the same lids. I originally bought these as a short term thing but the easiness for capping etc has made me continue with them. I usually give them a slight squeeze as I put the lids on so that I can tell how far along they are in carbonating, by how firm they have become.
Maybe just some new caps will solve your problem. I would have thought that one cap would fit all but, as stuster said, you may need to make sure you get the right ones for your bottles.

I would have thought 1 cap fits all. I must admit that these PET bottles are amongst a batch I received when I bought a second hand fermenter.

Possibly, I might keep the caps from this brew and reuse them. This will give me an idea whether the seal part which breaks off when you unscrew the cap, might have been faulty.

Sometime ago I was using PET bottles exclusively and had no issues.

 

[andrewg1978]

I had a similar issue....

Solution if using a new cap remember to remove ring from old cap first. When you bottle you will think it is on properly but it does not fully seal if the old ring is left on. Luckly I only lost about 4

Hope this helps

Andrew

 

[brettprevans]

ant PET softdrink lid should fit. Ive lost a few to the dog and replaced them with standard lids from 1.25L softdrink bottle (funnily enough it the 'yoy'll love coles' brand, so i have homebrand beer according to the caps!). havent had any problems with them.

re that stupid peice of plastic ring. I rip them off and dont use them. they are just a pain.

 

[trevc]

If you want to be careful, just buy new coopers PET caps. They're cheap, and at least you know the threads and seals will be in good shape. The black Coopers caps fit any soda bottle.

I don't buy this whole "PET bottles becoming porous" theory at all, sounds like BS. I've seen some very old bottles still holding coke with full CO2.

 

[winkle]

I'm pretty sure its a cap isssue. I've bottled batches in both plastic and glass and the PET bottled beers never seem to be as well carbonated (primed the same). I'd try using new caps - the seal should be as good as it gets.

 

[Adamt]

PET is O2 permeable, not CO2 permeable. If sufficiently carbonated PET bottles are going flat its either damaged PET (by chemical attack of some sort) or a lid problem. Carbonated PET bottles should not oxidise either due to the pressure difference.

 

[Cracka]

I don't use PET bottles but if you soak your caps in hot water at capping time, it will soften the seal, thus giving a better seal

on the bottle

 

[mossyrocks]

Thanks guys, looks like I'll dump my current batch of caps and try some new ones.

Or I do something with this keg I've had sitting next to my fridge for sometime.

Cheers

 

[trevc]

Just fill the keg and let it age

 

[Cracka]

Thanks guys, looks like I'll dump my current batch of caps and try some new ones.

Or I do something with this keg I've had sitting next to my fridge for sometime.

Cheers

Just send me the keg & I'll send you some new caps :wacko:

Sorted.