glass glass or plastic glass?

[butisitart]

bought a few erdingers recently, partly for the bottles, partly for brew inspiration. all 500ml, but then i noticed something odd. a couple of bottles were slightly taller (about 1cm, which is actually a fair lump). and they felt slightly heavier, glassier. these bottles have got a coat hanger looking logo in the numbers blurb at the bottom of the bottle, along with what i think is the year of manufacture. the slightly shorter, lighter bottles don't. went to a large barn retailer of commercial brews and checked out about 30 bottles over a couple of different german brands. same pattern. so..... my theory is that the taller bottles with the coat hanger logo is glass glass, with the yr of manufacture on them (i found one that had 94, and it was pretty worn where it has had a lot of jostles with other bottles on conveyor belts). the slightly shorter ones are therefore plastic mix, and kept separate by virtue of height.

there are different breweries using the same bottles, so it would be tall bottle in for certain brews, shorter bottle for others. it would make sense for different breweries to access the same bottles through recycling plants - keep a lot of overheads down.

interestingly, the labels soak off the glass glass a lot easier than off plas/glass. being the same company, i'm guessing they all go on with the same glue compound.

anybody know if i'm on the money or should i lay slow down on the amount of contemplative home brew i'm getting thru?? :icon_drool2:

also, i like the idea of glass over plastic, like leather over vinyl. is there any scientific support for either??

 

[peas_and_corn]

There are bottles made out of a blend of plastic and glass?

The big argument for glass bottles is they prevent oxygen from getting into the beer, which plastic does not. Aluminium stops light as well which is why it's better

 

[butisitart]

my understanding is that most 'bottles' these days are a glass plastic blend, but that's what i've been led to believe. let me see, back in the old days, my local commercial brewer went from all glass to glass plastic blend, or so it was widely reported at the time in the hushed corners of local pool halls. and the new bottles were certainly different in feel. there are certainly tapping sound and weight differences between different bottles of the same size, from different companies.

conundrum here folks - anybody out there who actually factually knows of such things and can shed some amber light on the subject??

i've also heard that coopers is the only commercial user of glass glass bottles in aus, and certainly their longnecks have a weightier feel than the others.

industrial engineers step up to your marks, please.


on the subject of plastic allowing oxygen into beer - (me no expert on this) - apparently it's an argument perpetuated by brewers who like to use the same caps 143 times then wonder why they're losing carbonation. so they blame it on the plastic. the other side of the argument is that the plastic (with a half life of 3000 yrs) doesn't deteriorate nearly fast enough to start malfunctioning after 4-5 uses. i not a lover of plastic anyway. the 30 PETs that came with my original brewpak are now used for fast chilling water for the ferment.

 

[danbeer]

Have never seen plastic glass bottles.
Given the wildly different melting points and compositions of plastic vs glass, its sounds like someone's been pulling your leg.

What is common is for (German at least) breweries to have two different bottle wights - one for re-use, and single use bottles.
Heavy ones often end up mixed in with the lighter ones for some reason - maybe as their last use?

(You can often pick the re-usable ones from the weight, and the wear around the shoulder)

 

[butisitart]

so are the re-use and single use both glass? or both plastic dressed as glass?
this is all a bit confusing for me, for example, if they are all glass, why are there such big weight differences (and 'tink' sound when you tap them) and why are some single-use vs reusable?
i bought a Landbier 500ml swing top and it feels like lead compared to most other bottles, and when it chills, it's just a glorious drink me magic deep chill.

my other question is, which may be part of my own confusion - are the big aust commercials eg vb, tooheys new, fourex - glass or plastic??

and another question is - should glass bottles have a seam down the side?? i was also led to believe that a seam down the side spelt plastic or glass plastic. (which apparently there is no glass plastic.) :unsure:

 

[Bribie G]

There is no such thing as a plastic and glass blend.

Get over it.

 

[Camo6]

Or is there? h34r:

 

[superstock]

The old reusable bottles and the single use bottles are both glass, it's just that the non refill, single use bottles are thinner and as such are more susceptable to breakage when recapping.
Even Coopers and old bottle exchange xxxx bottles have seams from where they are blow molded.

 

[butisitart]

cheers superstock - one of life's little mysteries sorted :huh:

 

[Mardoo]

I work in the wine industry and have a tendency to study whatever I come across. Not a scientist, but this is what I've learned, both from study and personal breakage experiments and experience.

There are a number of different formulas/mineral compositions that are used to make glass bottles. Some are optimized for greater plasticity at a lighter weight. NOT meaning there is PLASTIC in the glass. Meaning that it is just glass with slightly different stuff in it to alter its physical properties. They're of particular interest to folks who ship alcohol in bottles internationally.

 

[woodwormm]

Let me get this straight?...

Europe still washes and re-fills bottles commercially?

Didn't Australia give that up about 20 years ago?

 

[sp0rk]

Let me get this straight?...

Europe still washes and re-fills bottles commercially?

Didn't Australia give that up about 20 years ago?

Only because bloody whingers didn't think it was clean enough

 

[mr_wibble]

Let me get this straight?...

Europe still washes and re-fills bottles commercially?

Didn't Australia give that up about 20 years ago?

Yep.

Washing & re-using is the right way to do it.

And they make awesome home brew bottles. Look for the two wear-rings - one near the bottom, and the other just under where the neck joins the bottle body.
Sometimes the imported beers still use these bottles. Not the ones from aldi unfortunately.

 

[woodwormm]

i'll bet they run a pretty decent container deposit scheme to get the bottles back...

i'm sure there's pros and cons for washing and re-using as much as for crushing/melting and re-using, but until the east and west get on board with us front-runners in the centre states on a deposit scheme.... it's probably a null and void conversation....

 

[Davethebrewer]

This is how I understand it....
Aussie breweries are all now shifting to light weight glass.....to save on costs....both old and new glass have a coating to make the bottles slide together easily, this assists in mass conveyor transport.

 

[pk.sax]

Just to throw something in the mix, glass layers are bonded to plastic and carbon fibre layers in different layups for different strength/cracking characteristics. These are used in ... Space structures for example.

Quite simple really - plastic layer + bonding resin + glass layer.

Why anyone would go to the expense for beer bottles isn't quite fathomable. I've actually thought it'd make brilliant carboys. Inner glass layer bonded to outer plastic hard wearing layer. See through but not as fragile as glass.

 

[peas_and_corn]

I highly doubt there are beer bottles like that.

 

[butisitart]

aus gave up re-using bottles years ago cos we're too bloody lazy to do it, and it's probably commercially unviable small consumer population vs collecting. i'd argue though that coopers and the south aust model shows that you can do it if you want. but europe has the population and the infrastructure to do it. start looking seriously at euro bottles and you'll often see a year of manufacture on the blurb near the bottom of the bottle, and the double scuff rings from too many conveyor belts.
i'd suggest bottling cost saving in aus is in the form of a practice of saving costs on each bottle with no thought of ever re-using, as opposed to the practice cost saving on re-using vs manufacturing a new bottle every time you make a beer. it would be a lot cheaper to wash a bottle than manufacture a new one, which has to be washed and sterilised anyway. australia's a bloody wasteful country.
and Mardoo's comments above - rings a bell on my confusion - cheers!!

 

[butisitart]

what else i noticed with german bottles is that a lot of different brewers use identical bottles, then put paper labels on them. so one bottle manufacturer can be accessed by a whole lot of different brewers. there seems to be about 3 500ml common bottles and 2 common 330mls. so glass centro is the bottle makers, and for recycling, it doesn't matter which brewery they go back to, cos the bottles are all the same. contrast that here where every brewery has its own bottle. the cost of re-using goes through the roof cos there's no central agreement to ramp up the scale of economics. who knows what you pay at the bottle-oh cos aussie commercial brewers are too anal to work together. couple that with south aus being the only recyclers, and it's no wonder our glass is so rubbish that i thought it were plastic.
i think i need to visit my beer cellar and then think about something pleasant, like the world cup. we can't make decent bottles, but we can win the world cup.

 

[peas_and_corn]

All glass bottles have a percentage of recycled glass on them, since cullet reduces the melting point of the glass, lowering energy costs.

There is nothing inherently bad about Australian bottles, they do the job they are designed for- hold the product, bass a barrier for air and co2, provide something to stick the branding on and be as light as possible to save on material costs and shipping. Packaging will always be the biggest expense for a brewery (especially small breweries) and every saving makes a big difference.