"Oxygen transmissiblity of Plastic"

[abracadabra]

*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.

Isn't H2O in the gaseous state only when it has reached the temp. of boiling ?

Which is 212 degrees F or 100 degrees C at sea level and decreases as the altitude increases.

It seems to me that this would only be an issue if you brewed at something like 20,000 ft above sea level. Or you were to dump wort in at or near the boiling point.

Are the molecules of H2O that constitute relative humidity considered gaseous or still in the liquid form? I thought it was liquid althought they were contained within a gas.

I'm not a chemist but that seems pretty basic.

 

[olllllo]

Humidity (gaseous H2O) is always present.

 

[abracadabra]

Humidity (gaseous H2O) is always present.

It seems you are correct sir H20 in the form of humidity does consitute a gas

 

[casebrew]

The humidity would be higher in the carboy than out, so you will lose moisture. Anybody ever notice and measure the loss? Do you think that is why I never get 54 bottles out of a batch?

 

[Dave R]

I have several #2 Buckets and two #1 Pet 5 Gal water cooler bottles that I use for primaries and all make great beer. Of course, my beer doesn't sit around long enough to get oxygenated. I'm making 5 gal batches every two weeks or so. I haven't spent a penny on primaries yet.

 

[abracadabra]

Here's what you might be getting if you buy a number 7 other

Other plastics, including acrylic, polycarbonate, polylactic acid , nylon and fiberglass.

When they say fiberglass I wonder if they really mean epoxy resins with fiberglass

 

[casebrew]

Here's what you might be getting if you buy a number 7 other

Other plastics, including acrylic, polycarbonate, polylactic acid , nylon and fiberglass.

When they say fiberglass I wonder if they really mean epoxy resins with fiberglass

#7 is for non-recyclables. That is what it means. #7 could be combinations of other, recyclable plastics too. Like bottles with oxygen-proof linings that would be excellent fermenters. Fiberglass is a non-recylable combination, usually poly-ester resin, it is cheaper than epoxy.

And is there any evidence that any of those resins would harm beer? If so, is it used in multi-gallon water bottles?

 

[Jim Karr]

Actually, H2O will still move through a membrane even at freezing temperatures. That's what causes freezerburn, because the moisture in a package will still move through the package. I don't understand how , but it does.

 

[Denny's Evil Concoctions]

I know for a fact that blue watter bottles with #7 are polycarbonate.

And keep in mind these are food grade.

 

[user 4295]

And the wheels on the bus go round and......

 

[pa-in-utah]

So what is the concensus???? Can you use a #7 bottle or not? It seems to me that there is alot of "he said--- she said".....

Guess I am just stirring the pot again. Just trying to find out all the details. Who is right and who is wrong, or shoud I say incorrect.

From this link I gather #7 bottles should be ok to use.

http://www.alphap.com/basics/compare.html

Seems they will allow gaseous water to penertae more than O2.

 

[abracadabra]

I know for a fact that blue watter bottles with #7 are polycarbonate.

And keep in mind these are food grade.

You may be correct but not all blue bottles are #7 however.

 

[pa-in-utah]

Is polycarbonate bad? I am no scientist, so I do not understand the different "types or components" in plastic.

 

[Denny's Evil Concoctions]

You may be correct but not all blue bottles are #7 however.

Thus why I said Blue bottles WITH #7.

I've used #7's for years. In fact left a beer in one for 16 months once. People use the white platic carboys and they are O2 sieves.

Do you guys realise how long you'd have to leave beer in plastic for it even matter about O2 transfer?? A Long f'ing time.

 

[mad_legend]

Wow, my first post and I'm already whipping a dead horse! Sorry!

I have a lot (5) 5gal Sparkletts jugs that say "7" "Other" but they are made of "Unglass" which turns out to be Dupont Polycarb. I'm gonna skip the "is it ok to use" and go straight to "do they make stoppers etc in this size so I can do a batch (or 5) of Ed's Apelwein" I've never brewed anything other than Mr. Beer and I am currently on page 117 of 400+ pages of the Apelwein thread. (whew, thats a LOT of pages!) Anyhow, great site, glad I found it, keep up all the good work!

 

[Clintron3000]

"do they make stoppers etc in this size so I can do a batch (or 5) of Ed's Apelwein"

Did you ever find a stopper to fit? If so, what size?

This is an old thread, so how did the brew end up working out anyway? Did it taste like onions? or basement mold? or Sasquatch?