some bottles flat others ok

[paulgf]

I have brewed three or four lots using the supplied plastic bottles .  After bottling i ensure the caps are tightened, however with this last batch every other bottle is flat, the others are good,

Do you think its the bottles or know how long the plastic bottles should last?   As some are good and others flat i am thinking it cant be the brew.

Previously i have washed them in warm not hot water and a mild bleach solution.

Many Thanks Paul

[ozlizard]

I always get a few duds in each batch even though I tighten the lids as much as I can.

[iBooz2]

@paulgf  After bottling my PET batches, rinse them down and dry off with a clean tea towel. before boxing them up always give one last tighten whilst they are wrapped in my tea towel.  sometimes I get a little bit more torque and some snug up just that little bit more using this method.  Wet hands and wet bottles/lids deceive sometimes.

Give that a go next time.  Have not had any bottles lack fizz yet even with re-used lids.

Are you rinsing all the bleach residue out properly as any left over may kill your yeast?  Rinse well then sanitize them with a no-rinse sanitiser, drain well and they should be good?

Cheers - AL

[Shamus O'Sean]

Hey @paulgf, welcome to the forum.  I have been using the same PET bottles for over three years now and apart from a handful, they are all doing fine.  I always tighten the caps with a teatowel to protect my soft hands.

With the bleach treatment make sure you rinse the bottles well and allow them to dry before refilling.

Maybe see if you can get a-hold of some glass bottles (swing tops or crown seal type) to do a side by side comparison.  Having half of the batch end up flat is hard to explain.

Cheers Shamus

[Malter White]

Hi @paulgf

As mentioned above, use a tea towel to give you added grip and ensure a tight seal. Also, how are you priming your bottles? Are you using 2 carbonation drops per long neck? If you are using more than recommended you could be increasing the amount of carbonation which can cause the seals to fail ie. too much gas. PSSSSSHHHHH!

[Marty_G]

Teatowel shmeetowel get rid of that. Hand tighten then with a pair of multigrips do a last 1/4 turn to really crank those babies. Never fails.  Now that is tightening. 

Edited March 8, 2020 by MartyG1525230263

[Worts and all]

Never had a problem with the plastics over many cycles. A firm hand grip tighten, and a final check of all bottles before storage has always been sufficient. Of course if you don’t have a firm hand grip, or tend to limpness of the wrists ,you may need some assistance- - -

[Aussiekraut]

2 hours ago, MartyG1525230263 said:

Teatowel shmeetowel get rid of that. Hand tighten then with a pair of multigrips do a last 1/4 turn to really crank those babies. Never fails.  Now that is tightening. 

Multigrips for tightening, very very frightening me. Galileo....  

SWMBO is the bottler in the family and she hand tightens the PET bottles, without towels or anything and very, very rarely do we get a dud. And the's not the strongest wench out there.

 

[Malter White]

Multigrips?!! There phrase "sledgehammer to crack a walnut" springs to mind.  

[iBooz2]

4 hours ago, MartyG1525230263 said:

Teatowel shmeetowel get rid of that. Hand tighten then with a pair of multigrips do a last 1/4 turn to really crank those babies. Never fails.  Now that is tightening. 

I think Marty was "taking the piss" with multigrips.  He was thinking of stillson wrench!  Or was the stillson's for undoing the lids?

Cheers - AL

[BlackSands]

My daughter has the same issue but she has a mix of Coopers and Mangrove Jacks PETs.   She's mixed up the lids between the two brands and is now starting to think it's maybe a problem with MJ lids on Coopers bottles. 

In total contrast however, I have well over 100 PET's of mixed brands (not Coopers though), some of which are years old and I find, like @Worts and all the lids don't need to be super tight to ensure a good seal.  

[Marvin]

You can re prime the flat bottles.

[Waynealford]

I found that the white Morgan's lids developed splits from my first batch of GB, and the ones that haven't split are bulging on the sides and top.  Have swapped over to Cooper's black lids, no further issues, much stiffer plastic and a bit thicker too.  I agree that recranking with a teatowel for grip is a good idea.

[James Lao]

We have that rubbery material that you get in supermarkets and Bunnings for lining the bottom of cupboards and drawers etc.

I use a small piece for undoing pickle jars , jam jars and to give the bottles a final nip up when bottling.

Have used Coopers bottles for about 5 years, got new caps about 2 -3 years ago , no issues with carbonation.

Some brews take longer but they are usually all squeeze tight after a week.

Cheers

James

[Journeyman]

Only issue I have had with under-carbed beers is when I go browsing before time - some brews even 2 weeks isn't enough to carb properly - but I have had no beers that are under-carbed at 4 weeks.