Plastic bottles

[Yen]

I have started using Coopers Plastic bottles for my brews for the first time and most of my stout turned out to be really flat in these bottles, the few that I have put in glass bottles with caps are fine. I have checked the screw caps and they seem fine. Anyone can shed a light why beer is flat? 

Edited June 6, 2020 by yselcuk41@googlemail.com

[Malter White]

How much priming sugar did you use per long neck? How long has the beer stored before drinking and at what temperature were they stored at?

[Yen]

1 tsp of Muscavado per bottle, 1st bottle opened after 2 weeks from priming finished. The bottles stored in spare bedroom on shelf around 17-18C.

[iBooz2]

YEN Just a tip:  Probably not a good idea to use an email address as a login, that is unless you love spam (my absolute pet hate).  Every web site gets trawled by web bots, spiders, scanned, read, etc. so your email address will be a free for all for anyone who wants to target it.

You may have to leave your PET bottles a bit longer, remember they are plastic and will expand ever so slightly thus that take up of pressure is lost at first which the glass bottle do not do and hence glass pushes the CO2 into the liquid right from the get go. 

I have not had any problems with my PET bottles to date as they are left for quite some time before drinking, but have never made a stout in recent years so cannot comment on that. 

Have always use 2 x Coopers carb drops in the 740 ml PET's which does not quite seem like enough carbonation for my tastes so have moved over to using 1 x Coopers carb drop and 1 x cube of white sugar to see how that goes.  I might try some raw sugar using a measuring scoop jigger until I find the right balance.

Cheers - AL

Edited June 6, 2020 by iBooz2

[Yen]

Thanks for your tip about display name, just changed. I am also experimenting to priming second time to see if i can salvage it by doing it. Beer tastes really good, probably the best beer i have brewed from the kit. I will keep checking it. I wanted to move to plastic bottles because being easier then bottles and i want to continue to do so for all my brew providing it primes properly. Thanks again for your help.  All the best.

[Malter White]

39 minutes ago, Yen said:

1 tsp of Muscavado per bottle, 1st bottle opened after 2 weeks from priming finished. The bottles stored in spare bedroom on shelf around 17-18C.

Sounds like you're doing things right. The 17-18C might be a little cool for the yeast, so I reckon if you can't up the temperature a little just leave them a week or two longer and they should carbonate further.
I use PET bottles exclusively and rarely have any problems but I usually have enough beer on hand that they get at least a month in the bottle before drinking.
Late edit: I just saw you use Muscavado. I'm not familiar with it. Have you always used it previously in the glass bottles? If that's new to your process it could be the problem. I don't know, just putting it out there.

Edited June 6, 2020 by MUZZY

[iBooz2]

@Yen  Just edited my post to get rid of my reference to your email address within it before I was locked out of the edit.  Unfortunately it still shows in your first post where its says edited 1 hour ago:  Maybe you could ask admin to fix this for you.

Cheers - AL

Edited June 6, 2020 by iBooz2

[Otto Von Blotto]

1 teaspoon in a 750 mL bottle sound like much. What is muscavado? Never heard of it. 

[Malter White]

I just Googled Muscavado. Sounds like it's just another type of sugar so it should be fine to use without issues.

[Yen]

Yeah muscavado is only normal sugar with molasses added and I use it to prime my stouts all the time. I will leave them little longer see how it goes.

[Yen]

9 minutes ago, iBooz2 said:

@Yen  Just edited my post to get rid of my reference to your email address within it before I was locked out of the edit.  Unfortunately it still shows in your first post where its says edited 1 hour ago:  Maybe you could ask admin to fix this for you.

Cheers - AL

Would you be able to delete it? being your reply?

[iBooz2]

I cannot delete or edit your posts.  I did edit mine so that's all good.  Look at your first post, down the bottom, you edited it when you had your original email display name and now its stuck there until admin remove it, if they can that is.

Cheers - AL

 

[BlackSands]

1 hour ago, Yen said:

...the few that I have put in glass bottles with caps are fine. I have checked the screw caps and they seem fine. Anyone can shed a light why beer is flat? 

The fact that the few in glass bottles are well carb'd does strongly suggest an issue unique to the PET bottles.  Aside from following the suggestions above, and for what it's worth I can also add that my daughter experienced similar issues with PET bottles.  She had a mix of Coopers bottles and some other brand.  One suspect that was possibly causing the lids to not seal properly is the tamper ring -  and in her case she had mixed the lids from the two different bottle brands.  Some therefore recommend removing the rings - just in case.    

I encountered my first leaky lids just recently - when I squeezed one PET I could actually hear it so it might be worth holding an affected bottled up to your ear and giving it a good hard squeeze. 

[Yen]

1 hour ago, iBooz2 said:

I cannot delete or edit your posts.  I did edit mine so that's all good.  Look at your first post, down the bottom, you edited it when you had your original email display name and now its stuck there until admin remove it, if they can that is.

Cheers - AL

 

Thanks Al,

I have reported to Admin, hopefully it will get sorted. Thanks again.

[Yen]

35 minutes ago, BlackSands said:

The fact that the few in glass bottles are well carb'd does strongly suggest an issue unique to the PET bottles.  Aside from following the suggestions above, and for what it's worth I can also add that my daughter experienced similar issues with PET bottles.  She had a mix of Coopers bottles and some other brand.  One suspect that was possibly causing the lids to not seal properly is the tamper ring -  and in her case she had mixed the lids from the two different bottle brands.  Some therefore recommend removing the rings - just in case.    

I encountered my first leaky lids just recently - when I squeezed one PET I could actually hear it so it might be worth holding an affected bottled up to your ear and giving it a good hard squeeze. 

Interesting, this is my first ever plastic bottles so i wasn't sure what was going on, I will keep trying different ways. Removing rings might make difference I guess but again proof is in doing it. Thanks again for your message. 

[BlackSands]

 

[Shamus O'Sean]

Hi @Yen, 1 teaspoon is not enough to carbonate a 740ml bottle of beer well, if you want to drink it within two weeks.  It would be fine if you left them for over 6 months.

The glass bottles, having no flexibility, have probably carbonated just a bit more, as stated by @iBooz2 above.

I have not experienced it, but some say that the PET's do allow some gas to escape over time.  You would not notice it over a few weeks.  I have had brews in the PET's for at least six months and I never noticed any reduction in carbonation.

[Lab Cat]

1 hour ago, Shamus O'Sean said:

I have not experienced it, but some say that the PET's do allow some gas to escape over time.  You would not notice it over a few weeks.  I have had brews in the PET's for at least six months and I never noticed any reduction in carbonation.

Same here. I don't read any brew 'experts' sites or blogs, I've found there's too much theorizing. I've had beers in PETs that were perfectly carbonated months later. I don't usually keep beer that long, but there's been no problems doing so in plastic.

As to Yen's question. Very likely not enough sugar, and not stored for long enough. While stouts should probably be lowered carbed anyway, they also fare better after an extended period in storage, so the lower sugar amount shouldn't make too much difference when they're really ready for drinking. 2 weeks isn't anywhere near enough.

I've found all my dark beers are better over longer term storage. Even the ones I called fails were drinkable after 6 months. 

[Panther Branch Brewing]

I've been using the 740ml Coopers bottles a couple years now and have had no problem with them. I find they seal very well. I have not noticed any loss of  pressure even after a few months storage.

[Yen]

20 hours ago, Shamus O'Sean said:

Hi @Yen, 1 teaspoon is not enough to carbonate a 740ml bottle of beer well, if you want to drink it within two weeks.  It would be fine if you left them for over 6 months.

The glass bottles, having no flexibility, have probably carbonated just a bit more, as stated by @iBooz2 above.

I have not experienced it, but some say that the PET's do allow some gas to escape over time.  You would not notice it over a few weeks.  I have had brews in the PET's for at least six months and I never noticed any reduction in carbonation.

Thanks for your message but my bottles are 500mls not 740 that is the reason I use tsp of sugar.

[Yen]

19 hours ago, Lab Cat said:

Same here. I don't read any brew 'experts' sites or blogs, I've found there's too much theorizing. I've had beers in PETs that were perfectly carbonated months later. I don't usually keep beer that long, but there's been no problems doing so in plastic.

As to Yen's question. Very likely not enough sugar, and not stored for long enough. While stouts should probably be lowered carbed anyway, they also fare better after an extended period in storage, so the lower sugar amount shouldn't make too much difference when they're really ready for drinking. 2 weeks isn't anywhere near enough.

I've found all my dark beers are better over longer term storage. Even the ones I called fails were drinkable after 6 months. 

That is one of the reason I use Muscavado because it's not like normal sugar and also gives nice caramelly flvr towards the beer a little. I will keep the bottles little longer see how it develops over the time. Thanks for your message. 

[Shamus O'Sean]

55 minutes ago, Yen said:

Thanks for your message but my bottles are 500mls not 740 that is the reason I use tsp of sugar.

That makes complete sense.  I use a teaspoon of sugar in my 450ml Grolsch fliptops.  Not sure about your under carbonation issue with the PETs now.

[thebeerpig]

Sometime ago a mate of mine who had taken up home brewing asked me if I wanted all of his Coopers pet bottles as he was moving entirely to glass. Reckoned he was consistently pouring the odd pet bottle that was flat or nearly flat in each brew he had bottled with them. I took them off his hands thinking he may not have been tightening the lids properly as the lids looked to be in good condition. I’ve been reading on the forum that others were having the same problem so I thought I would mark his bottles, and bottle 6 of them at a time, along with my bottles in case his actually were a bit dodgy. I did a brew along with 6 of his and took all the bottles out of secondary yesterday. All the bottles were nice and tight, except for one of the marked ones, which felt squishy. I opened it up to see if I could spot a cause and found the bottle had a hard to spot moulding flaw in the bottles smooth sealing surface that was letting the gas escape.

Put the bottle upside down on my printer’s scanner to get a picture of the flaw. If anyone is still have trouble with flat pet’s it may be worth checking the tops of their bottles in case the flaw is not a one off.

[Yen]

Hi mate,

Thanks for your message, sorry I am bit late seeing it. once the are empty I will look in to them individually. Thanks again.

[BlackSands]

On 6/7/2020 at 11:15 PM, Shamus O'Sean said:

Hi @Yen, 1 teaspoon is not enough to carbonate a 740ml bottle of beer well, if you want to drink it within two weeks.  It would be fine if you left them for over 6 months.

I routinely prime 750ml bottles with 1 teaspoon/1 sugar cube (4.5g).   That works out to be around 2.5 volsCO² or 6g/litre - that's perhaps not super fizzy but certainly quite appropriate for a majority of styles and I certainly find it to be more than adequate generally.   

I do however get the impression that many folks here prefer megaswill-levels of fizz in their beer.  I'm not sure what a carbonation drop actually weighs (I'm sure they vary) but if you did the following calculation:

Coopers 250g pkt / 60 drops = 4.16g/drop.   2 drops per 750ml = 8.32g/bottle = 11g / litre = 255g/23litre batch = 3.7 volsCO²        (Using Beersmith Calc @18ºC )

That's an explosive amount of carbonation and surely can't be right!  I read elsewhere however that the target weight of the drops are in fact supposed to be around 3.2g -  which would mean the packet weight should actually be around 195g.    Anyway, a couple of 3.2g drops equates to around 2.8volsCO2 - that's still getting up there on the fizz scale so I'm a little surprised when I read accounts like the following:

On 6/7/2020 at 10:31 AM, iBooz2 said:

Have always use 2 x Coopers carb drops in the 740 ml PET's which does not quite seem like enough carbonation for my tastes

 

As for the OP query - It seems some 'specialty' sugars aren't quite as fermentable as the sucrose (table sugar).  Not sure if Muscavado is one of them?   But either way, 1 teaspoon in 500ml bottle really should be more than enough.  If it is directly equivalent to sucrose then that's 3.1volCO² - that's a lot!  If however it's fermentability is more like that of molasses then it's gonna be around 2.5volsCO^{2  -} which is the number I usually work to as mentioned above. 

 

Edited June 30, 2020 by BlackSands