PET Bottles

[Paul B 77]

Hi all. I've only recently bought the Coopers craft brew kit. I love the craft brew kit for its handy size and simplicity. I'm brewing a simple craft brew (Diablo) every week, carbonating in the PET bottles (which I've never used before) for a couple of weeks and drinking within a week. The Diablo generally produces a nice head. I've noticed though recently, after having used the PET bottles 6 or 7 times each, that I'm getting 1 or 2 bottles in a batch that are dead flat. I'm wondering whether this could be because of the PET bottles. My questions are - how long do the PET bottles last? How do you know that they have passed their use by date? Is the flat beer an indication that the PET bottle is no good? Appreciate any insights.

[Lab Cat]

I used PETS for well over a year and they were fine. I use mostly glass now, but always bottle a few PETs in each batch too. I would get the odd dud, and it's probably just that bottle. The cap might have leak or the bottle thread might have an issue. Some bottles might just fail after a while, so I bin them.

[Malter White]

Hi @Paul B 77.
The PET bottles are all I use. I get the occasional dud as well. My first reaction if I get a flat one is to ditch the lid. It's not often the bottles are faulty. They can be but it's usually the lid.
If you get a dud bottle, just check the rim to ensure there's no glitches in it. A good seal = bubbles.  

[Paul B 77]

Thanks guys. Appreciate your help. I marked the latest bottle that went flat so I can see if it fails again. Didn't think to mark the cap though!

[iBooz2]

@Paul B 77 I use both the Coopers PET and some glass 345 ml 150 lashes stubbies.  Good idea to mark any flat bottles and lids to see if there is a pattern in your case.  Might also be a good idea to get some more PET bottles into your collection and leave the batches a little bit longer, try for a month before drinking and see if that improves things.  That is if you are not forgetting to put the required 2 x Coopers carb drops into some bottles.  Get a fool proof system going here with the bottling sugars so you don't overlook any on bottling day.  See following tip.

Someone posted a pic a while back re a nick in the top rim of one of his PET bottles and got me thinking how this would occur.  When I opened my last couple of boxes of new Coopers PET bottles it dawned on me.

If using a box cutter, Stanley knife and the like, it is possible to nick the top rims of some bottles if the blade extends too far into the box when slitting the tape that runs down the middle of the box.  This would make all the bottles in the middle row of the box vulnerable to damage by possibly having their top rims nicked by the blade.  Its far better to slit the side edge tapes first then lift up the two centre cardboard sections slightly then do the final slit length-ways down the middle of the box.  Do this with a blade that is just long enough to cut the tape and nothing else inside the box.  Just an idea and possible tip for anyone else.

Also don't forget to use the"@MUZZY method" of 1 x Coopers carb drop and 1 x white CSR sugar cube per PET as this make a big difference with carbonation.

Cheers - AL

 

[Barramullafella]

I have read that Coopers PET bottles are lined inside to help keep contents from going flat. Sounds good. I was wondering if Morgan's PET bottles have same lining. Anyone know? Cheers.

[Classic Brewing Co]

I have used 3 types of PET bottles over the years & I feel they all produce good results, I for one always use new caps for each brew.

I start with removing the break off section that sits on the bottom of the rim & of course as @MUZZY  & @iBooz2  say it pays to check the condition of the bottle before using.

Since I have been using new PET CAPS for each new brew, I haven't had a dud. I always use extreme care with the bottles so although some may disagree about the new caps each brew

all I am saying is - it works for me. I figure $3.00 is not much when you can knock out 2 x cartons of beer for about $20.00.

Cheers.

[ozdevil]

personnaly i have never liked  pet bottles  for brewing   mind you i have never even bothered with long necks  when i have bottled just stubbies

i just don't know why  i don't like pet bottles,  but have  seen similar things discussed elsewhere and other mates having issues

what they have told me that the mangrove jacks  caps are not great  on coopers and vice versa

i also think   if ya cross threaded a cap (not saying a person does this)  on the pet bottle this may not help you getting a good seal  and allows the  co2 to escape resulting in flat beer


the only time i have had flat beer in a stubby is on the screw top stubbies  , but you can easily overcome that with them

 

[Malter White]

@Barramullafella I sometimes wonder where certain information comes from.  I'm not going to dispute the lining theory but even Coopers own description on their online store (below) doesn't mention it.  

COOPERS DIY BEER PET BEER BOTTLES AND CAPS (15 X 740ML)

1622

15x Coopers DIY Beer 740ml PET bottles and reusable screw-on plastic caps.

Bottles are also reusable, lightweight and shatterproof.

[Journeyman]

A quick Google shows plenty of refs to Coopers PET's using 'Ox-bar' construction, a barrier layer between 2 x PET layers. But most of them seem to refer to 500ml bottles - maybe @Coopers DIY Beer Teamcan add more?

[Barramullafella]

57 minutes ago, MUZZY said:

@Barramullafella I sometimes wonder where certain information comes from.  I'm not going to dispute the lining theory but even Coopers own description on their online store (below) doesn't mention it.  

COOPERS DIY BEER PET BEER BOTTLES AND CAPS (15 X 740ML)

1622

15x Coopers DIY Beer 740ml PET bottles and reusable screw-on plastic caps.

Bottles are also reusable, lightweight and shatterproof.

I found this bit of info, Muzzy.   How Long Do Plastic Pet Bottles Last? | The HomeBrew Forum

[jamiek86]

The only trouble I have had with brand new pet bottles is why using carbonation drops provided with Mr beer pack. Otherwise using correct doses of priming sugar bottles should easily be ok for a dozen or more uses before replace a lid. Also should be able to store for over 6 months before loose carbonation. Coopers tell you yourself they are short term storage and recommend ageing most of there beers for 3 months. Anything intended long term use glass.

[Malter White]

3 hours ago, Barramullafella said:

I found this bit of info, Muzzy.   How Long Do Plastic Pet Bottles Last? | The HomeBrew Forum

Thanks for that. I use PET bottles exclusively but if I'm honest I do prefer the aesthetics of glass. However I love the practicality of plastic more than aesthetics. Light, safe (no bombs) and reusable lids. I can't say plastic has affected the quality of my beer drinking experience because I haven't used glass in decades so I can't compare any differences. 

[Journeyman]

55 minutes ago, MUZZY said:

and reusable lids

I re-use my crown seals. Just make sure you have an opener with a 'bar' type lifter and not a corner type and if they don't crease they work next time perfectly well.

[bambooze]

I have been using PET bottles for 20 + years with minimal failures, perhaps 1in 200.

Occasional bottle splitting, some bottles 5-6 years old. Some cap failures, usually reused up to 5 or 6 times.

The big issue is the style of caps available on the market now, my failure rate has suddenly jumped to 1 in 10 or more.

The old style caps had a plastic seal which rarely failed to seal. My supply of these older caps is now exhausted and I can't find a source any longer.

The new caps with a raised ridge to effect the seal between bottle and cap just don't cut it. Have tried them with different breeds of bottles.

If any one knows where to find a supply of the older style, please let me know. 

[Classic Brewing Co]

I prefer Coopers Longnecks & I like Grolsch bottles, I have used Corona stubbies with success over the years there are pretty much PET bottles involved. I have rarely had an issue with them only one now & again that lacked fiz. I will gradually fade the out & eventually go all glass as to me it tastes better when poured into a glass. I agree with their storage life as the hardness slowly starts to diminish & you end up with flat beer.

[Aussiekraut]

I'm generally not a friend of 750ml bottles, glass or PET. I have glasses that hold stubbies, half litres and litres but not a single glass for 750ml. My "drinking" beers go into stubbies with the occasional PET for carbonation testing and my wheat beers go into 500ml (glass or PET). "sipping beers", so in essence dark ales, porters, stouts etc I usually bottle into the Coopers PETs. These are beers I can use a small glass to fill and then put it away until the next refill. Not sure why but that's how I've always handled it. 

As for the PETs, the 500ml water bottles are fine, however the lid isn't particularly sturdy and seems to bend outwards a little when under pressure. I guess "lightly sparkling" water has a lot less pressure than a beer carbed to 2.8vols. They do hold ok though and aren't used for long term storage or maturation. The Coopers plazzies are pretty good though. You get the odd dud, I agree. but generally, they hold pressure well over a year and longer. Whenever I get a dud, I usually throw the lid out and replace it with a new one. I get maybe two or 3 a year, regardless whether the beer is a year old or 2 months. While it is two or three too many, I can live with that.

 

 

[jamiek86]

14 hours ago, bambooze said:

I have been using PET bottles for 20 + years with minimal failures, perhaps 1in 200.

Occasional bottle splitting, some bottles 5-6 years old. Some cap failures, usually reused up to 5 or 6 times.

The big issue is the style of caps available on the market now, my failure rate has suddenly jumped to 1 in 10 or more.

The old style caps had a plastic seal which rarely failed to seal. My supply of these older caps is now exhausted and I can't find a source any longer.

The new caps with a raised ridge to effect the seal between bottle and cap just don't cut it. Have tried them with different breeds of bottles.

If any one knows where to find a supply of the older style, please let me know. 

Have to agree with this statement i also have 2 lots of the new lids without the plastic lining in them and with different bottles get a few more duds than usual even after replacing multiple times.  A brand new box of bottles is fine for ages the trouble i have had is newer lids on older bottles that to the eye look fine. Perhaps this is the problem built that little bit different and so are the lids.

[Classic Brewing Co]

I have found a slight difference between Morgan's & Coopers PET bottles & even the ones you can get from Brewcraft.

However as @Aussiekraut says occasional PET for carbonation testing    

this is a good practice to have a few on hand to check progress, when reaching the bottom of a brew I usually save these for last fill.

[jamiek86]

3 hours ago, CLASSIC said:

I have found a slight difference between Morgan's & Coopers PET bottles & even the ones you can get from Brewcraft.

However as @Aussiekraut says occasional PET for carbonation testing    

this is a good practice to have a few on hand to check progress, when reaching the bottom of a brew I usually save these for last fill.

I used to do same if split a batch between glass and PET. Now im kegging i usually do a few PET bottles first then Keg the rest so not tipping FV at end for bottles.

[Classic Brewing Co]

Sounds good, I would love to have a keg set-up as since I have moved here I met more people & made more more friends I am entertaining more.

[BlackSands]

I'm another that has been using PET's for years, although I also have some 500ml glass swing-tops.  Some of my PETs and lids have been in service for quite some years - 6 years at least I'd say.  Only now am I starting to have occasional seal failures - one, maybe two flat beers per batch.  And it seems to be roughly 50/50 bottles or lids.  I just remove the lid, pop in a sugar cube to re-carb and then reseal with a different lid.  I then give it a good hard squeeze test and listen for air escaping...   that usually tells me if it was indeed the lid at fault.  If not, i.e. I hear air escaping then it's pretty certain that it's a dodgy bottle.  It get's tossed and sadly I lose the beer as well.  Though, I guess if you were really tight you could carefully pour the contents into another bottle!  

I actually prefer the 500ml swing-tops, the volume suits a lot of my larger glassware: in practice 1 bottle = 1 full glass.  I have around 100 750ml PETs which I will steadily replace, perhaps just keeping a dozen or so of the newer ones.  I also have a dozen 1lite PET's which I never use.  Bought those back when there was more than one beer drinker in the house! 

[Classic Brewing Co]

2 minutes ago, BlackSands said:

I'm another that has been using PET's for years, although I also have some 500ml glass swing-tops.  Some of my PETs and lids have been in service for quite some years - 6 years at least I'd say.  Only now am I starting to have occasional seal failures - one, maybe two flat beers per batch.  And it seems to be roughly 50/50 bottles or lids.  I just remove the lid, pop in a sugar cube to re-carb and then reseal with a different lid.  I then give it a good hard squeeze test and listen for air escaping...   that usually tells me if it was indeed the lid at fault.  If not, i.e. I hear air escaping then it's pretty certain that it's a dodgy bottle.  It get's tossed and sadly I lose the beer as well.  Though, I guess if you were really tight you could carefully pour the contents into another bottle!  

I actually prefer the 500ml swing-tops, the volume suits a lot of my larger glassware: in practice 1 bottle = 1 full glass.  I have around 100 750ml PETs which I will steadily replace, perhaps just keeping a dozen or so of the newer ones.  I also have a dozen 1lite PET's which I never use.  Bought those back when there was more than one beer drinker in the house! 

I use them but now following other members comments re: using for them just for early checking of carbonation I am about to reduce the amount I use. I prefer Coopers Longnecks & Grolsch Swing Tops - these are my favorite & I could easily use them all of the time, in fact I am going to try the larger 750ml as well. 

I want a pop when I open the bottle & I like a lingering head. 

[BreweyMcHops]

On 3/3/2021 at 6:29 AM, Malter White said:

@Barramullafella I sometimes wonder where certain information comes from.  I'm not going to dispute the lining theory but even Coopers own description on their online store (below) doesn't mention it.  

 

I will ! There is no WAY a plastic coopers bottle is constructed of two separate layers, with the inner one being a lining. ( lookup how PET bottles are made , it's a hot single lump of plastic injected with air)  Thats modern CANS , nowadays there is a plastic lining inside cans and there are videos about it . 

Even if it has a bulletproof magic wonderful lining , bottles don't leak through the sides they leak at the join between cap and bottle  

 

I think that bloke is trolling us