My beer is Skunked

Any discussion about non-specific Braumeister brewing techniques can be discussed here. E.g. "How to make a starter?", "What's the best way to store my grains?", "Which pH meter do you recommend?", ...

My beer is Skunked

Unread postby gandalf the brew » Sun Aug 05, 2018 4:51 pm

I didn't have any room in the beer fridge for all the bottles and now the hot weather has skunked them.
I put a couple of bottles in the fridge on Friday, opened a bottle this afternoon and I couldn't drink it.
It was vile, a sweet tasting IPA is not very nice with a sour after taste.

So I have just been on Gumtree and found a good used fridge and am at present wiring it with an STC1000.
Lesson learnt, drink more beer rather than throw it away.
Carrots are good for your eyesight, but beer doubles your vision
gandalf the brew
 
Posts: 154
Joined: Tue Sep 19, 2017 5:02 pm
Location: Near Norwich
Model: 10 litres (2015)

Re: My beer is Skunked

Unread postby mashy » Mon Aug 06, 2018 6:41 am

That doesn't add up for me. I hold all my bottles at ambient and then chill as I want them. I know they have hit 30c unfortunately. But I know they are intrinsically safe when bottled. Where are you storing it?

Has keeping all your bottled in the fridge previously 'hidden' an infection?

I have made some rubbish is the past, when trying things out and some old old kits and that has taken years to drink?
User avatar
mashy
 
Posts: 2606
Joined: Sat Aug 29, 2015 12:43 pm
Location: Mercia
Model: 20 litres

Re: My beer is Skunked

Unread postby gandalf the brew » Mon Aug 06, 2018 7:00 am

Here is something curious, it's only the PET bottled beers that have the off taste, the glass swing tops are OK.
All the bottles were treated the same as far as cleaning and sterilising goes.
Carrots are good for your eyesight, but beer doubles your vision
gandalf the brew
 
Posts: 154
Joined: Tue Sep 19, 2017 5:02 pm
Location: Near Norwich
Model: 10 litres (2015)

Re: My beer is Skunked

Unread postby mashy » Mon Aug 06, 2018 9:03 pm

Nope. That fits & makes sense. PET is gas permeable... Meaning the air had got to it. In warm weather that would be more pronounced. Were they in the light too.

I use glass for that reason. Problem solved imo.

Make "withdrawals" from the bottle bank, recycle your the caps. Beer bottles are brown for a reason but I like clear glass... you can see what's going on but lob a towel over them if you can't store them in the dark.
User avatar
mashy
 
Posts: 2606
Joined: Sat Aug 29, 2015 12:43 pm
Location: Mercia
Model: 20 litres

Re: My beer is Skunked

Unread postby IPA » Tue Aug 07, 2018 6:07 am

mashy wrote:Nope. That fits & makes sense. PET is gas permeable... Meaning the air had got to it. In warm weather that would be more pronounced. .


That PET is oxygen permeable is to me an internet myth. Try this experiment. Fill a PET bottle with hot water then quickly empty it and tighten the cap. As he bottle cools it will partially collapse inwards. You can now spend many years waiting for the oxygen in the atmosphere to penetrate the bottle and reflate it to the outside air pressure. In fact it will never happen until the bottle starts to decompose. A PET bottle full of carbonated beer at at least 1.5 times atmospheric pressure will not admit oxygen at a lower pressure.
IPA
 
Posts: 180
Joined: Tue Feb 25, 2014 8:16 am
Location: France
Model: 50 litres

Re: My beer is Skunked

Unread postby mashy » Tue Aug 07, 2018 7:26 am

Sorry I do not agree.
Oxygen permeable is low level & over time. Its not a tea strainer :D

The wine industry use PET & HDPE for maturing product because of the degrees of gas permeability. Have also proved this.

Different folks different strokes
User avatar
mashy
 
Posts: 2606
Joined: Sat Aug 29, 2015 12:43 pm
Location: Mercia
Model: 20 litres

Re: My beer is Skunked

Unread postby Mashman » Tue Aug 07, 2018 2:44 pm

gandalf the brew wrote:Here is something curious, it's only the PET bottled beers that have the off taste, the glass swing tops are OK.
All the bottles were treated the same as far as cleaning and sterilising goes.



Were the PET bottles the Coopers ones with Ox-Bar barrrier ? They are supposed to have a laminated impermeable layer. I have used these extensively, storing beer up to a year with no issues.

M
Mashman
 
Posts: 117
Joined: Wed Feb 04, 2015 4:06 pm
Location: Canterbury, Kent, UK
Model: 20 litres

Re: My beer is Skunked

Unread postby gandalf the brew » Wed Aug 08, 2018 8:00 am

Not Coopers, but these ones seem to be the same:

http://www.home-brew-online.com/equipment-c40/plastic-beer-bottles-brown-pet-screw-cap-500ml-basic-p1732

I didn't know about the Oxygen permeable situation with PET.
I was given several of these about 2 years ago with the intention of filling just one per batch so I could test the carbonation without opening a bottle.
But silly me did 10 of the batch with these, never before & never again, I'll stick to just one tester as normal.
Last edited by gandalf the brew on Wed Aug 08, 2018 2:09 pm, edited 1 time in total.
Carrots are good for your eyesight, but beer doubles your vision
gandalf the brew
 
Posts: 154
Joined: Tue Sep 19, 2017 5:02 pm
Location: Near Norwich
Model: 10 litres (2015)

Re: My beer is Skunked

Unread postby Mashman » Wed Aug 08, 2018 8:24 am

They look the same but no mention of oxygen barrier.

M
Mashman
 
Posts: 117
Joined: Wed Feb 04, 2015 4:06 pm
Location: Canterbury, Kent, UK
Model: 20 litres

Re: My beer is Skunked

Unread postby mashy » Wed Aug 08, 2018 8:53 am

I am sticking to glass..
User avatar
mashy
 
Posts: 2606
Joined: Sat Aug 29, 2015 12:43 pm
Location: Mercia
Model: 20 litres

Re: My beer is Skunked

Unread postby IPA » Wed Aug 08, 2018 11:47 am

mashy wrote:Sorry I do not agree.
Oxygen permeable is low level & over time. Its not a tea strainer :D

The wine industry use PET & HDPE for maturing product because of the degrees of gas permeability. Have also proved this.

Different folks different strokes


Try the experiment that I suggested. The wine industry does not store wine under pressure. Incidently they also use porous wooden casks. I repeat oxygen cannot penetrate anything under higher positive pressure.
IPA
 
Posts: 180
Joined: Tue Feb 25, 2014 8:16 am
Location: France
Model: 50 litres

Re: My beer is Skunked

Unread postby mashy » Wed Aug 08, 2018 2:19 pm

The wine industry does not store wine under pressure - do you not think Fine Champagne
shipping in pop bottles will catch on ? :shock: :shock:
User avatar
mashy
 
Posts: 2606
Joined: Sat Aug 29, 2015 12:43 pm
Location: Mercia
Model: 20 litres

Re: My beer is Skunked

Unread postby IPA » Wed Aug 08, 2018 3:54 pm

mashy wrote:The wine industry does not store wine under pressure - do you not think Fine Champagne
shipping in pop bottles will catch on ? :shock: :shock:


During the degorgement process of champagne production the cork is completely removed allowing oxygen to enter the bottle. But I fail to see your point with regard to my proof that oxygen cannot enter a PET bottle that has a higher internal pressure than the atmophere outside. I am not saying that oxygen cannot pass through PET but only if the internal and external pressures are the same. If you carry out the test I originally outlined even then it will take years if ever for oxygen to enter the bottle.
IPA
 
Posts: 180
Joined: Tue Feb 25, 2014 8:16 am
Location: France
Model: 50 litres

Re: My beer is Skunked

Unread postby mashy » Wed Aug 08, 2018 6:14 pm

I understand your point re pressure differential.
The thought of champagne in pop bottles was intended to be funny and lighten the moment.

IPA wrote: I am not saying that oxygen cannot pass through PET

... I have to say, that seems to be a change of heart from "internet myth". :?
User avatar
mashy
 
Posts: 2606
Joined: Sat Aug 29, 2015 12:43 pm
Location: Mercia
Model: 20 litres

Re: My beer is Skunked

Unread postby IPA » Thu Aug 09, 2018 6:45 am

mashy wrote:I understand your point re pressure differential.
The thought of champagne in pop bottles was intended to be funny and lighten the moment.

IPA wrote: I am not saying that oxygen cannot pass through PET

... I have to say, that seems to be a change of heart from "internet myth". :?


No data has been published proving that oxygen can penetrate PET under internal pressure. It has just been repeated time and time again on the internet by people with no scientific skills as a fact. Before the internet repeated unsubstantiated stories were called urban myths. That some types of PET are porous is a fact. A couple of years ago a bought some tonic water in 25cl bottles which I intended to use for yeast storage but after several months all of the carbon dioxide had escaped through the walls of the bottles and the tonic water was completely flat. That is a fact. If any scientific tests have been done on PET porousity it COULD have been in the same way. That is to say by pressurising a bottle with oxygen and then measuring the drop,if any,of pressure over a period of time. I say could because until the proper data is published we have no way of knowing.
If unproven statements are continually repeated this problem will continue. The same goes for the title of this thread. Skunky (mythyl mercaptan) tasting beer is caused by light waves of certain frequency striking the hop compounds in beer.
Whereas as in the original post the author was refering to perceived oxidation of his beer. If someone stumbled over this thread with no previous knowledge then he or she would refer to oxidised beer as skunked beer someone else would pick up on it and repeat it and so on until it also became an internet myth.
The moral of this is do not repeat something unless you have absolute proof that it is true.
Mashy please do not take these remarks as personal to you.
IPA
 
Posts: 180
Joined: Tue Feb 25, 2014 8:16 am
Location: France
Model: 50 litres

Next

Return to General Brewing Discussions

Who is online

Users browsing this forum: No registered users and 3 guests