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Worthog

Old PETs. End of life, or temporary blip?

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I've been saying on here that I'm moving to All-Glass as bottling receptacles.

I'm there now, I've only needed 4 weeks of finished goods inventory to keep me happy "as a Worthog in mud", over summer.

Over the last 2 months I have changed from Carb Drops to a measured Dextrose carbonation regime.

I have found the reducing number of PET bottles in inventory are lacking carbonation compared to the glass longnecks of the same batches, all of which are sub 4 weeks bottled.

The question is;

  • Are my ageing PETS, 10-15 cycles, finding their limit (always new caps)?
  • Has it got something to do with Dextrose carbonation?
  • Is it that nightime ambient carbonation temps are getting to low teens here in NE Victoria?

Thoughts and Cheers

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What measurement/weighting system are you using for the Dextrose? Are you bulk priming or measuring an amount into each bottle?

Many people have used the PET bottles/caps on many more then 15 brews with no issues but for the price maybe it could be the safe option to replace the caps and see how you go?

Lower temps will definitely have an effect too, it should still carbonate, but depending on the yeast being used, if it gets very cold it may go dormant and cause some issues. Lower temps will generally cause longer carbonation times.


Cheers, Mitch.

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Yeah but lower temps would affect the whole batch, not just the portion in plastic bottles. All other things being equal, the only thing I can think of is that the plastic ones aren't sealing properly. 

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Posted (edited)

I slowly cycle through my PET bottles by discarding 3 or 4 "rejects" (based on colour and stress marks) each time I bottle. If I have a really over-carbonated batch I might chuck out significantly more than that, which is always sad and annoying.

Chucking them out involves putting them into another box which holds 60 bottles, and when it's full I put them in the recycling and buy 60 more to replace them.

Edited by King Ruddager

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I no longer refill my PET's I have been selling  off 75 at a time for $30.00 the only ones however, I am keeping currently have 1 year aged Stout and Dark Ales in them and they have been brilliant for that ... but as they empty they will go too ... 

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Sorry to hear I am not the only one having lost faith in PET's, on my most recent post I expressed my dismay at finding my stout that I bottled in may last year was flat, the bottles were all new as were the caps, there was a problem with these bottles a couple of years back with a batch leaking through holes in the bottom, I have a few cartons with stains to remind me! My change to sparkling water bottles continues to be a success, important that the original caps are reused as PET caps do not seem to seal as well. 

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3 hours ago, King Ruddager said:

I've never had an issue with flat beer in PET bottles for what it's worth

Neither have I until recently. The efficiency of these PETs must have a life span which I think some of mine have reached as I have had no replacement plan over the years.

I would recommend PETs to any brewer, although I personally prefer glass.

Cheers

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3 hours ago, King Ruddager said:

I've never had an issue with flat beer in PET bottles for what it's worth

me either, mine have had multiple brews thru them, changed the caps tho 

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Posted (edited)

I have always used new caps, 100%

It may be the dextrose. I use the same volume measure as for sugar, for 750ml.

But that does not gell with glass of the same batch being ok, maybe a tiniest amount reduced.

Cheers

Edited by Worthog

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I use a mixture of glass and PET's.  Probably have about 60 PET's on rotation over 50+ brews.  Mostly use the same caps.  I have chucked two PET's and their caps in that time due to no carbonation.  I feel sorry for them because it was probably my fault for not tightening them enough in the first place.

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Posted (edited)
On 3/28/2019 at 3:48 PM, King Ruddager said:

I've never had an issue with flat beer in PET bottles for what it's worth

Likewise, and some of my PET's are over 4 years old and I've never had to replace a single cap.   However I recently helped my daughter get through her 2nd batch and we stumbled across a several bottles that were partially flat to a greater or lesser degree, and one that was totally flat.  (I have a hunch she may have missed priming that one!).  She has a mix of PET's - Coopers and Mangrove Jacks but it was only the Coopers bottles where the occasional beer was flat.   😟

Edited by BlackSands

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I put my PET bottles in the dishwasher to sterilize them. That royally screwed them, even though they looked ok. Since I stopped that my PETs have never given me an issue, except for cleaning them. 

 

The only issue I have is the dimples at the bottom. Hard to clean. Has anyone seen non dimpled PET bottles?

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9 hours ago, Potatoes said:

I put my PET bottles in the dishwasher to sterilize them. That royally screwed them, even though they looked ok. Since I stopped that my PETs have never given me an issue, except for cleaning them. 

 

The only issue I have is the dimples at the bottom. Hard to clean. Has anyone seen non dimpled PET bottles?

PETs are really simple to clean. Rinse immediately after pouring. Then later, put a pet-cap-ful of non-scented bleach in, fill with cold water and let stand over night.

Rinse in the morning for crystal clear PETs. I used this procedure successfully for past 18 months on the advice of PB2. 

Cheers.

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The only non dimpled ones I've seen are the still water ones which aren't any use for beer. Either that or those really old ones with the black plastic thing at the bottom. Good luck finding any of those anymore 🤣

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17 hours ago, Worthog said:

 I used this procedure successfully for past 18 months on the advice of PB2. 

Cheers.

Yep, I’m doing the same now after reading your post a few months back. Works a treat.

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I just had another dead PET, which is 3 from one batch, even though about 50% of the bottles in that batch were glass with no flat glass bottles.

Previously I have had 2 dead PETs in 1000 bottles. So I believe there is an end-of-life factor after many usages.

This was one of my first batches bottled with measured Dextrose rather than carb drops.

I am now convinced that those PETs have either reached end-of-life as containers, or less likely, the lids have failed due to dextrose debris, which I am sure is not the case as I always clear the top of the bottle if I have spilled 'sugar'.

I have used PETs for more than 2 years with no problems, always capped with new tops.

There is absolutely no doubt now, that my glass is pouring better beer than my plastic. More consistent carbonation, better longevity in the bottle, slightly better taste.

I am about to dump all my old PETs, although this is not a statement degrading the usefulness, reusability and effectiveness of PETs which have taken my brewing to where I am now.

Cheers

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4 hours ago, Worthog said:

I am about to dump all my old PETs

going rate or fair price on gumtree is $5 for 15 .... I usually bundle them with something I got with other stuff I have bought .... like a FV or something .... next lot I sell will be 6 boxes of 15 with an old temp controller i have just updated will ask $50 for that ... 

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19 hours ago, Worthog said:

I just had another dead PET, which is 3 from one batch, even though about 50% of the bottles in that batch were glass with no flat glass bottles.

Previously I have had 2 dead PETs in 1000 bottles. So I believe there is an end-of-life factor after many usages.

This was one of my first batches bottled with measured Dextrose rather than carb drops.

I am now convinced that those PETs have either reached end-of-life as containers, or less likely, the lids have failed due to dextrose debris, which I am sure is not the case as I always clear the top of the bottle if I have spilled 'sugar'.

I have used PETs for more than 2 years with no problems, always capped with new tops.

There is absolutely no doubt now, that my glass is pouring better beer than my plastic. More consistent carbonation, better longevity in the bottle, slightly better taste.

I am about to dump all my old PETs, although this is not a statement degrading the usefulness, reusability and effectiveness of PETs which have taken my brewing to where I am now.

Cheers

Bottled a brew of Stout this morning, I was fortunate that I decided to take them from the carton and put them in a cupboard as one of them had stared to leak through the bottom, this is the first leak I have had for about three years, before I ditched the bottle I filled it with with water to see where it was leaking from, it appears to be from one of the lobes on the bottom not the centre. I think I will ditch the lot and stay with the water bottles. 

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17 hours ago, MartyG1525230263 said:

going rate or fair price on gumtree is $5 for 15 .... I usually bundle them with something I got with other stuff I have bought .... like a FV or something .... next lot I sell will be 6 boxes of 15 with an old temp controller i have just updated will ask $50 for that ... 

I wouldn't sell my 90 odd PETs as I am convinced they have reached the end of their reliable life, so these will all go into the recycle bin.

Cheers

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Posted (edited)

I think you are on the right track Worthog. You will never catch a craft brewery putting its beer in PET bottles. Heck, you don't even find the cheapest mega swill packaged in PET.  The reason is PET is porous....Loss of carbonation is only one of three possible problems with PET bottles. The other issues are staling and loss of hop aroma. 

Frankly I don't understand why a serious home brewer would use PET bottles....

Cheers,

Christina. 

Edited by ChristinaS1
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Posted (edited)

I don't ferment in plastic anymore either (although I have never bottled in PET). Glass all the way.  Sorry Coopers.

Cheers,

Christina.

Edited by ChristinaS1

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8 hours ago, ChristinaS1 said:

I think you are on the right track Worthog. You will never catch a craft brewery putting its beer in PET bottles. Heck, you don't even find the cheapest mega swill packaged in PET.  The reason is PET is porous....Loss of carbonation is only one of three possible problems with PET bottles. The other issues are staling and loss of hop aroma. 

Frankly I don't understand why a serious home brewer would use PET bottles....

Cheers,

Christina. 

That is interesting, where did you get your info on the 3 possible issues with PET bottles is that published as i would love to read over it ... as far as loss of carbonation every PET bottle of soft drink i have opened over the last 4 decades has been highly carbonated ... surely if it was problem PET bottles would not be used by drink manufacturers ...  so using that logic they can't be porous ... 

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I am getting out of PET bottles not because they go flat, or because the beer is inferior I just hate the instability of the actual bottle shape whether full or empty ....   

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Posted (edited)

All plastics are porous. PET is one of the better ones, although PET is better at blocking CO2 (larger molecule) than O2.  Beer is very sensitive to staling from oxygen, more so than soda is. If you Google it there are many possibly links, albeit most are from the plastics and recycling industries.

They are working on technology to improve PET bottles with various liners, impregnating the resin with oxygen scavengers, and UV blockers....Soft drinks bottles are ordinary PET.

One issue is that amber PET is it difficult to recycle. Recyclers don't make much money on coloured PET. They prefer clear or light blue.

Another possible issue is that PET is not heat stable. It can leach a chemical called antimony into water or beer that is stored at temperatures of 60C or higher, such in an enclosed shed or car.

https://www.ncbi.nlm.nih.gov/pubmed/17707454

Cheers,

Christina.

Edited by ChristinaS1

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