"Oxygen transmissiblity of Plastic"

[casebrew]

Here's an intreresting link I found : <shttp://www.alphap.com/basics/compare.html>

With an interesting chart.

Check the right hand column, "recycle numbers". The O2 column is oxygen transmisiliby, lower is better.

Some stuff I noticed: #7 bottles pass only 1/2 as much as #1 bottles. So #7 is TWICE AS GOOD FOR BEER, as far as staling goes. #2, as in bucket fermenters, pass 53 times as much oxygen as a #1 bottle. So #7 plastic would be 100 times better than a plastic bucket. I'll repeat that:

#7 PLASTIC IS BETTER THAN #1 PLASTIC.

#7 PLASTIC IS 100 TIMES BETTER THAN A PLASTIC BUCKET.

So, if a plastic #2 bucket is just fine, then it just don't matter, does it?


Note also the CO2 transmissability column, that each of those plastics pass CO2 at 4 to 7 times the speed of oxygen. SO:

YOUR BEER WILL GO FLAT, BEFORE IT GOES STALE, IN ANY KIND OF PLASTIC.

I did some googling on the #1 carboys. All the sales literature seems to compare them to glass. Nothing to compare them to the mass market water jugs. No "Our jugs are better than #7 jugs because ______"

 

[Sir Humpsalot]

Don't forget to take thickness into account. Does O2 permeability decrease linearly or exponentially with an increase in thickness?

I don't know the answer to that, but I know enough to ask the question...

 

[the_bird]

Here's the problem.

Recycle Code 7 means "other" plastic.

Plastic ID Code "7" is for the other plastics except above mentioned 6 groups.

Source: http://www.kenplas.com/topic/recyclelogo/

Alternatively,

Properties: varies according to constituent resins
Statistic: In 1999 there was minimal usage of resins in the 'other' category in plastic bottles.


Description: The category of "Other" includes any resin not specifically numbered 1, 2, 3, 4, 5, or 6, or combinations of one or more of these resins.

Packaging applications: Three and five gallon water bottles, certain food product bottles

Recycled products: Plastic lumber, custom-made products

Source: http://www.earthodyssey.com/symbols.html

Now, your website states that Polylactide is Recycle Code 7 - that DOES NOT mean that all Recycle Code 7 is Polylactide. It simply means that Polylactide is not one of the other six that can be recycled.

So, if you buy a bottle that is Code 7, it COULD be Polylactide; if it is, you're in luck.

It also could be pretty much anything else, which would put you SOL.

 

[abracadabra]

Very interesting since #7 is listed as "Other" how would you know that you are getting PLA plastic or something else?

Maybe it is I don't know.

 

[kornkob]

Well, you'd order PLA plastic from your manufacturer---- the recycle code isn't there to help you spec out your purchase, really. It's there to aid in recycling efforts.

 

[casebrew]

I guess all those guy brewing in #7 have been just flat out lucky then? All of them?

Anybody got some examples of water bottles labeled #7, that are known to be somthing other than Polylactide? Anybody? Beuller?

But again, anydamn stuff is better than the ubiquitous #2 bucket.

 

[the_bird]

Do what you want to do - but your link proves nothing.

 

[ayrton]

I'm just happy that better bottles and fermentation buckets are 100% recyclable.

<-- Tree hugger

 

[ayrton]

But again, anydamn stuff is better than the ubiquitous #2 bucket.

Meh, the bucket seems to work fine for a primary. If it ain't broke, don't fix it and all that...

 

[Cheesefood]

I guess all those guy brewing in #7 have been just flat out lucky then? All of them?

Anybody got some examples of water bottles labeled #7, that are known to be somthing other than Polylactide? Anybody? Beuller?

But again, anydamn stuff is better than the ubiquitous #2 bucket.

I've aged two in plastic bottles and I didn't particularly care for either batch. I'm not 100% sure it's due to the bottle but evidence points. I'm doing a final test where I split my melomel into two vessels (out of necessity). I'll post the differences.

 

[Tony]

Use glass!!!!

::runs out of the thread::

 

[Cheesefood]

*MVTR stands for Moisture Vapor Transmission Rate in g-mil/100in. 2/24hr. MVTR is a measure of the passage of gaseous H2O through a barrier. The lower the rate, the longer the package protects its contents from moisture and ensures the moisture content of the product remains the same.

#1: 2.0
#7: 18-22

 

[kornkob]

So are you staying that the nubmers mean exactly the opposite of what the original poster said?

 

[user 4295]

Let's not forget the flavor scalping associated with other types of plastic. Flavor scalping that does not occur with PET plastic. Other types of plastic use plasticizers in the manufacture, PET does not. PET or polyethylene terephthalate, is made by polymerizing tere-phthalate with ethylene glycol. It also will not absorb any odors or flavors from the products in them so there is no chance of passing any odors or flavors from batch to batch. The same cannot be said of other plastics. Even food grade HDPE #2 (high density polyethylene).

 

[casebrew]

Let's not forget the flavor scalping associated with other types of plastic. Flavor scalping that does not occur with PET plastic. Other types of plastic use plasticizers in the manufacture, PET does not. PET or polyethylene terephthalate, is made by polymerizing tere-phthalate with ethylene glycol. It also will not absorb any odors or flavors from the products in them so there is no chance of passing any odors or flavors from batch to batch. The same cannot be said of other plastics. Even food grade HDPE #2 (high density polyethylene).

Do you think bottled water companies want their water to pick up flavors in the fridge?

 

[user 4295]

Do you think the bottled water companies really care if the water you buy from them picks up flavors? They don't if they are bottling their water in #7 plastic carboys!

 

[casebrew]

*MVTR stands for Moisture Vapor Transmission Rate in g-mil/100in. 2/24hr. MVTR is a measure of the passage of gaseous H2O through a barrier. The lower the rate, the longer the package protects its contents from moisture and ensures the moisture content of the product remains the same.

#1: 2.0
#7: 18-22

So, you'll lose 10 times as much to evaporation? Anybody here ever been concerned with evaporation from a fermenter before? Anybody ever measure/ calculate vapor, um, plus or minus?

Oh, That's water vapor, not liquid.

 

[Cheesefood]

So, you'll lose 10 times as much to evaporation? Anybody here ever been concerned with evaporation from a fermenter before? Anybody ever measure/ calculate vapor, um, plus or minus?

Oh, That's water vapor, not liquid.

No, you're letting in 10 times more humidty.

 

[casebrew]

Let's not forget the flavor scalping associated with other types of plastic. Flavor scalping that does not occur with PET plastic. Other types of plastic use plasticizers in the manufacture, PET does not. PET or polyethylene terephthalate, is made by polymerizing tere-phthalate with ethylene glycol. It also will not absorb any odors or flavors from the products in them so there is no chance of passing any odors or flavors from batch to batch. The same cannot be said of other plastics. Even food grade HDPE #2 (high density polyethylene).

Any Evidence that polylactide is not as good as PET? As I tried to point out, bottled water companies would not use a bottle that picks up flavor from the einvironment- like onions in your fridge.

Anybody have any direct experience? I sure have a water jug that was made to fit in a fridge- #7.

 

[casebrew]

No, you're letting in 10 times more humidty.

In, out, whichever. Any evidnece that it is a significant amount?

 

[casebrew]

I've aged two in plastic bottles and I didn't particularly care for either batch. I'm not 100% sure it's due to the bottle but evidence points. I'm doing a final test where I split my melomel into two vessels (out of necessity). I'll post the differences.

Did you mean #7 water jugs, or "better bottles" ?

What probelms? Too much evaporation? Flavor scalping? Until I came along, the only problem ever mentioned was oxygen transmission, leading to stalenesss, the wet cardboard taste.

 

[the_bird]

You're still working under a bad assumption.

Where do you see ANY evidence that the plastic water cooler bottles are polylactide? The fact that polylactide is #7 does NOT mean that all #7s are polylactide. Unless you can establish that the water cooler bottles are, in fact, made of polylactide (using some form of evidence other than their recycle number), there's no argument here.

 

[casebrew]

You're still working under a bad assumption.

Where do you see ANY evidence that the plastic water cooler bottles are polylactide? The fact that polylactide is #7 does NOT mean that all #7s are polylactide. Unless you can establish that the water cooler bottles are, in fact, made of polylactide (using some form of evidence other than their recycle number), there's no argument here.

There has also been absolutely no evidence presented that fermenting in a #7 water jug has ever done any harm to anybody's beer. Only the theory that it may be more oxygen pemeable. It just ain't necessarily so.

That was not the first site I visited while looking into this. I learned that #7's can be plastics used in combinations. Like bitchen stuff that has an extra treatment to the inside to prevent some pertinent problems. I.E., #7 bottles could be PET, with a nitrogen gas treatment to make them even better.

 

[casebrew]

Another hour of googling has found me very little pertinant data.

Just that the <7> plus PC under the triangle means Poly Carbonate. Have I seen <7> PLA bottles? They would be awesome fermenters. And i don't see anything wrong with PC either. And you know the bottler thought it was good enough for consumer water, whatever the resin.

PLA is not very recyclable, yet, but is supposed to be compostible.

It's PVC containers that have the loads of plasticisers- mostly shrink wrap.

PET can leach antimony into it's contents. Other plastics leach other stuff, in parts per BILLION. I think PET does too.

I just looked at every plastic container in my house. All have the number, plus under the number, the initials for that type of resin. Only one #7, under the <7> said 'other'. No help there.

 

[user 4295]

I just spent the last hour of my life compiling the info to make the case for PET over other types of plastic, and then I realized..... I don't give a sh!t! Ferment in a fuc@ing old shoe if you prefer!

 

[Denny's Evil Concoctions]

agh. I've posted this half a dozen times in this forum in the last year or more.

#7 blue water cooler bottles are a POLYCARBONATE COMPOSITE. The SAME stuff Nalgene bottles are made of, all be it thinner.

So more O2 permisible than PETE but still not bad. And to be honest you will lose CO2 before you will see O2 permeate.

 

[delboy]

I just spent the last hour of my life compiling the info to make the case for PET over other types of plastic, and then I realized..... I don't give a sh!t! Ferment in a fuc@ing old shoe if you prefer!

Just for arguments sake should that be an old nike or old reebok .

This thread is like a return to aristotlean logic what with the whole all #7 are this but not all # are that, 'you, you are number six, i am not a number i am a FREE MAN'

What about some emperical science here has anyone had beer gone stale in these containers or tasted flavour transfer ie onions in the fridge to the liquid in the bottle.

 

[Bobby_M]

I use better bottles, I already have them, sunk cost, so I don't really care either way. However, I would suggest that there are probably 20 other factors in your brewing process that would affect the flavor of a batch moreso than any difference in fermenter makeup (unless we're talking about something highly porous like wood or unglazed ceramic). If buckets are marginally acceptable, I'm sure you'll be fine with your #7 water jug.

What I'm trying to figure out is what your goal is. Are you looking to convince everyone to stop wasting money on PET bottles?

 

[kornkob]

Oooo---- homebrew geek fight!

*streaks across room*

ALUMINUM POTS SANITIZED WITH BLEACH SO YOU CAN MAKE CORONA IN YOUR PARENTS' BASEMENT IS TEH AWESOME!






*stops to poke a pile of pooh with a stick*

 

[abracadabra]

Anybody got a PLA carboy, Or know where I can get one.
I'll be happy to run an experiment.