Glass vs Plastic Bottles for LT storage

[MartinHaworth]

It's commonly held that for long term storage of our 'big' beers, we need to use glass rather than plastic. But is it true?

I have in front of me two bottles of Dubbel beer, same batch, each one year old - one glass, one plastic.

This afternoon I will open both / photograph / taste / comment.

I will be opening these beers purely in the name of science.

 

[Appleyard]

Oh, I say, well done! I will be very instresterd to flinged out what you descrubber. Just make sure you can tripe plopperly. Oh my, is that the time!

 

[MartinHaworth]

Visually the difference is clear, with the plastic bottled beer showing the characteristic darkening of an oxidised beer.

The glass bottled beer retained the characteristic 'nose' of a dubbel, whilst the plastic bottled version was lacking in aroma.

In terms of flavour, the glass bottled beer is OK, with some abbey character, but perhaps past it's best.....but the plastic bottled variant is both bland, hot and sherry-like.

In summary, I intend to finish the glass-bottled beer. The plastic bottled beer is drain-pour.

TL/DR: Use glass for anything intended for more than a couple of months.

Cheers

Martin

 

[Jordang]

Good info

 

[Appleyard]

Visually the difference is clear, with the plastic bottled beer showing the characteristic darkening of an oxidised beer.

The glass bottled beer retained the characteristic 'nose' of a dubbel, whilst the plastic bottled version was lacking in aroma.

In terms of flavour, the glass bottled beer is OK, with some abbey character, but perhaps past it's best.....but the plastic bottled variant is both bland, hot and sherry-like.

In summary, I intend to finish the glass-bottled beer. The plastic bottled beer is drain-pour.

TL/DR: Use glass for anything intended for more than a couple of months.

Very interesting. Before you chuck the boottles out: is there a "best before" date on either or both? If so, what is it?

 

[Chippy_Tea]

There have been a few threads about this here and on our American sister site, plastic is air permeable so over long periods ageing you run the risk of your beer oxidising there have also been lengthy discussions about putting alcohol into bottles not designed for the purpose, it has been suggested if you use bottles not designed for the job chemicals can leach into your beer, i believe plastic bottles designed for the job have a membrane or barrier inside to stop this.

 

[MartinHaworth]

Thanks all.

@Chippy_Tea yes, these are coopers bottles that apparently have a special film that prevents oxygen ingress....

I wonder where the sweet spot is to use plastic, and what the implications are for those of us who do competitions / inter club stuff.

In the recent Norwich vs Beer Boars inter club comp, 'the rules' said PET but several brewers used glass without penalty. (Norwich won!)

Thanks again

Martin

 

[Appleyard]

yes, these are coopers bottles that apparently have a special film that prevents oxygen ingress....

I wonder where the sweet spot is to use plastic, and what the implications are for those of us who do competitions / inter club stuff.

I've looked at recently-purchased PET bottles of cider, and the BBE is stamped as "Sept 2021". Since I've recently bottled about 70L of cider into the same bottles, I'm taking that as my approximate "drink by" date!

Maybe "it's different for beers".

Edit: Ah! I have now recognised my faux pas re the BBE on your bottles. "When were they bottled" would have been a better question! However, the answer is already given. A year. Interesting.

 

[chillipickle]

Take this with a pinch of "salt" my local brewery sells amongst other sizes, 1 ltr glass bottles and 3ltr plastic bottles.My group of friends who regulary buy beer from the brewery, all agree that beer from the glass bottles taste better than the 3ltr plastic bottles at home.

The beer is always fresh, probably same week bottled.Their 22 pint pressure barrels are the best by far if you have the means to keep it chilled.

 

[Appleyard]

Hm. Where do we keep our bottles? In an outhouse? In a cool room? In either of those places in a box lined with a substance imnpermeable to oxygen? It would not have to be completely gas-tight to reduce oxygen ingress to a tiny fraction viz. an "unprotected" bottle, and would not need to be pressure resisting.

 

[foxy]

I am pretty sure that the Coopers bottle say indicates 1 year before the oxygen get through the barrier, not sure how long it is for glass bottles as the caps are a smaller area it.

 

[Binkei Huckaback]

If PET bottles have a barrier lining and the manufacturer say has a finite lifespan, doesn't this essentially make them single use?

 

[An Ankoù]

I use Perrier bottles for beers that I would otherwise consider draft or quick drinking beers. When I've kept them for many many months, the bottle tends to lose it's rigidity so there's certainly evidence of diffusion through the plastic. I don't think I've experienced the degree of oxidation documented in the OP, though. I'll have to look and see if I can find any old bottles and taste again.

 

[foxy]

If PET bottles have a barrier lining and the manufacturer say has a finite lifespan, doesn't this essentially make them single use?

No, lots of brewers use the Coopers bottles with the barrier multiple times, just not good to store beer for any length of time. Temperature has a part to play too.

 

[aamcle]

I did a little test unplanned but still relevant.

I found two bottles of the same batch of beer that had been stored together in a filling cabinet one was in a Coopers bottle, one in Glass and both over 8 months old.

The beer in glass was significantly better in terms of head retention and flavour.

One random test is hardly a proof but it's good enough for me, glass for long term storage


Atb. aamcle

 

[MartinHaworth]

Coopers website say that the film on the inside of the PET bottles can help reduce oxidation for 'up to 18 months'. I wonder whether vigorous cleaning with a bottle brush might contribute to the degredation of this film.

One of the 'gaps' in my brewing is that I have never (no, not once) used a crown capper. I have several cornies, lotsa grolsch bottles and lots of Coopers PET bottles.

I enjoy having a couple of 'big' beers squirreled away in dark places. I think that for these beers at least, I need to move over to glass and crown caps.

Cheers

Martin

ETA: I have several bottles left of this dubbel in both glass and plastic. I reproduced the same result with another pair of bottles last night.

 

[Appleyard]

What I don't like is all these 500ml glass bottles, which are a pain to store, clean, fill, cap, clean, etc. In the Old Daze there were quart bottles, which might be better. I've seen litre swing-tops, but does anyone use them? I've also seen 1.9l swing top stainless steel bottles, but these are over a tenner each, and ugly.

 

[Hop_it]

I spent most of my working life in the plastics industry, and although I did not work directly with PET, I did pick up some knowledge along the way:

• Pure/unmodified PET bottles are permeable to both oxygen and carbon dioxide. They are therefore unsuitable for packaging anything that is sensitive to oxidation, e.g. beer, wine and many other foodstuffs, unless of course the bottles are very thick walled.
• However, PET can be coated or blended with other polymers and/or additives to reduce the permeability, and caps may also contain oxygen scavengers. The type of barrier system is normally chosen according to the type of product being packaged, and the required shelf life. So, a bottle designed and produced to package one type of product is not necessarily suitable for packaging something else - at least not for any length of time. Also, there is no way to tell by looking at it . . . . . even if it is coloured brown.
• Finally, many of the coatings and additives (e.g. oxygen scavengers) have a limited life. Coatings such as PVdC (which is a very effective oxygen barrier) are very thin, and can be worn away over time.

So, the bottom line is - use glass and good quality caps.

PS - The attached article goes some way towards explaining why PET bottles are not all made equal.

 

[Argentum]

Did you squeeze the plastic bottle and cap it with zero air in the headspace? That seems to improve things for awhile.

As an aside, I noticed that within the past few months Coopers brand PET beer bottles have disappeared from the marketplace here in the States, so I emailed them with an inquiry as to why, and they referred me to the Mr. Beer site. Unfortunately Mr. Beer packages less bottles in a box and charges more.