Hard Data...

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brazedowl

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So I've heard all kinds of stories about what to use for secondaries because of the oxygen permeability of certain types of plastics. I've been using 5 gallon primo water jugs, which are labeled as #7 (other). I've not experienced any problems with crazy off flavors in my wine, but then again my tongue may be off.

Therefore I am proposing to collect the hard data!

1) Boiling 5 gallons of water to drive off any dissolved oxygen.

2) Taking a dissolved oxygen reading using the shiny new dissolved oxygen probe I just ordered for my Environmental Science Class.

3) Taking readings as often as I can, day to day, or at most a week apart, over the course of a year to determine if any oxygen is indeed penetrating in significant amounts.

4) Present the findings here to be published in the auspicious Journal of Homebrewology for all to see.

I <3 the scientific method. :)
 
Excellent. As a fellow plastic jug fermeterator, I'm looking forward to your findings
 
I'm very interested in this. I'm a mythbusters kind of guy myself (which may be why I work an R&D job :) ). I'm always interested in testing what people have always heard or have always said :).
 
Sweet! Any confounding factors at work? Does pH, viscosity, etc. affect how much dissolved oxygen will show up?
 
May I offer some suggestions to make this a bit "tighter" scientifically?

Don't use water...the criticism will be that water in a plastic carboy does not have same characteristics in regard to oxygen permeability as does wine/beer in a carboy. This is probably a minor gripe...but doing the experiment with an actual material of interest makes it a better experiment.

Second...you are going to take measurements and get data...but how will you know if that data tells you something meaningful? You need a control that tells you that it is meaningful (and how meaningful is it?).
In this case you want to compare your data set using plastic to a sample where oxygen permeability is effectively nil (i.e. a glass carboy). Only by comparing the measurements from the plastic to the measurements from the glass will you know if there is a significant increase in dissolved oxygen in your liquid. You also correct for the intial amount of dissolved oxygen in the material at the start of the experiment.

Third, say you see a difference....what if that effect you saw only happens to that one plastic container you tested? You need to have at least two plastic containers to measure for good results (Three to five containers for even better statistical power!)

Since you are going to spend a year doing this, may as well do it right.
 
I love the idea... only problem I see is that won't opening the carboy to take readings however often allow oxygen in each time thereby upping the readings? I agree as well that using water may not be the best test subject compared to an actual beer.
 
I love the idea... only problem I see is that won't opening the carboy to take readings however often allow oxygen in each time thereby upping the readings? I agree as well that using water may not be the best test subject compared to an actual beer.

Yet another reason why you need a control.... theoretically air would enter each by the same amount every time you took a reading...any differences you see could then be attributed to how the different containers let air through.
 
Yeah, I think the OP needs to run a control sample in a glass carboy of the same size, taking measurements from both carboys with the same frequency.
 
I love the idea... only problem I see is that won't opening the carboy to take readings however often allow oxygen in each time thereby upping the readings? I agree as well that using water may not be the best test subject compared to an actual beer.
Don't use water...the criticism will be that water in a plastic carboy does not have same characteristics in regard to oxygen permeability as does wine/beer in a carboy. This is probably a minor gripe...but doing the experiment with an actual material of interest makes it a better experiment.

The problem with using beer/wine as a comparison is the fact that there won't bee free oxygen. The way that oxygen messes up beer/wine is that it combines with molecules in the brew and oxidizes it and therefore won't be floating around to be detected by my the probe.

Yeah, I think the OP needs to run a control sample in a glass carboy of the same size, taking measurements from both carboys with the same frequency.

True yes. I'll try to locate one. This would also account for any Oxygen added while taking the sample. It should have the same amount enter for both as long as I take the sample for the same amount of time in the same manner for each sample.

Third, say you see a difference....what if that effect you saw only happens to that one plastic container you tested? You need to have at least two plastic containers to measure for good results (Three to five containers for even better statistical power!)

Tis part of the plan. Did not write it in though. :)

Sweet! Any confounding factors at work? Does pH, viscosity, etc. affect how much dissolved oxygen will show up?

They have an effect on the probe but it will be calibrated to work in tap water so the readings should be sound.
 
plastics do interact with the environment like that but very slowly so checking weekly is probably far too often. I'd wait 3 months before the first reading, start with lightly carbonated water, and test for loss of carbonation.

I would also seal the carboy with something other than an airlock, CO2 and oxygen can travel through the water in the airlock and the effect of this probably is much larger than travel through the plastic.

Find small plastic bottles, 2L size or so of different kinds of plastics and compare to a 1/2 gallon glass bottle, seal all of them hermetically for 3 months and later open and test carbonation level and for oxygen. It might take a couple years to notice much of a difference.
 
plastics do interact with the environment like that but very slowly so checking weekly is probably far too often. I'd wait 3 months before the first reading, start with lightly carbonated water, and test for loss of carbonation.



Maybe, but he can start checking and then make a decision based upon the initial results. If it doesn't change for the first three weeks of the experiment, he is probably good to wait a couple of months before a re-check.

I would also seal the carboy with something other than an airlock, CO2 and oxygen can travel through the water in the airlock and the effect of this probably is much larger than travel through the plastic.



If both control and plastic carboy will have airlocks, you can therefore control for the air coming in through the airlock. As long as both carboys are sealing identically, then it shouldn't matter how much air passes through them.

Find small plastic bottles, 2L size or so of different kinds of plastics and compare to a 1/2 gallon glass bottle, seal all of them hermetically for 3 months and later open and test carbonation level and for oxygen. It might take a couple years to notice much of a difference.

I disagree....using small plastic bottles defeats the purpose of the experiment. We are interested in oxygen permability in containers used for brewing. The surface to liquid ratio in soda bottles may be different and thus yield different results. They therefore may not be applicable to larger containers. Second, comparing a 2L plastic bottle to a 1/2 gallon glass bottle defeats the purpose of using a control....they may be different enough to not be able to effectively compare them. Third, hermetically sealing is not correct as internal pressue may affect how oxygen permeates into the container. Why study when a sealed container when you want to know about one that isn't sealed (i.e. an airlocked carboy?).
 
The problem is that we know that PET is relatively impermeable because it is used for bottled carbonated beverages with a pull date 6 or 12 months in the future but we know an airlock is pretty permeable as CO2 and oxygen can migrate through water. So an experiment designed using an airlock on both side by side will get identical results if it is run for a few weeks or months because migration through the water in the airlock will be the dominant cause of gas exchange. You would have the same result if you tested them with the top open, the gas will go through the water more slowly but the contents of both will get the same amount of oxygen.

Using smaller size bottles helps shorten the time frame because 2L of water is a smaller reservoir than 5 gallons but it can be done in the exact same container too.
 
To me, oxygen permeability in a triangle-marked &#8220;7&#8221; carboy is pointless.
I would never use one for storage regardless of the length of time. Just a bad practice.
The chances of leaching BPA or other chemicals with estrogenic activity, or toxins or carcinogens is not worth the couple dollars saved. Further, anything other than PETE or glass ... for instance polycarbonate, polypropylene or polyethylene ... *are* specifically known to be much more permeable to oxygen than PETE.

I would only use carboys that are marked PETE &#8220;1&#8221;.
Plastic carboys of non-PETE composition I only use for storing things like dechlor&#8217;ed water that I am going to use.

For longest term storage, bottling is pretty much the most practical way to do it. That said ...
For storage of up to 2 years, the safest bet is actually with a Better Bottle or a fairly new glass carboy that has not been banged around or gone thru freeze/thaw cycles (microscopic cracks in glass carboys also allow in oxygen over time).
Regular, non-Better-Bottle carboys made of PETE I&#8217;d suggest are safe for bulk storage of about 10 months or so.

Could you possibly get away with storage for a much longer length of time - or in some other vessel? ... sure, you might just get 5 years storage in a goat's stomach and have the wine still drinkable.
The question is how big of a loss is it if your batch goes south. Anecdotal stories of someone's cousin's brother's uncle storing successfully for multiple years using nothing more than a jerry-can and a balloon don't mean that is a storage method which can be relied upon.

Part of oxygen permeability is from the composition material ... part from the structure as manufactured ... and part, significantly from the closure. Better Bottle actually uses a specific high pressure blowing/molding process that was designed to maximize carboys resistance to oxygen permeability that other PETE carboys (the ones from Absopure for example) do not.

Not to get too off on a tangent here, but, the closure/stopper is a bigger culprit than the carboy generally.
The common silicone or PVC stoppers are NOT suitable for long term storage and are notorious for allowing in oxygen long term.
The best against oxygen infiltration are PETE stoppers, the closure products from Better Bottles, and also natural rubber stoppers and carboy-caps. Although with natural rubber, very old ones will eventually dry out.
The old, stinky black or red neoprene stoppers are also decent against oxygen infiltration ... it just the odor potentially getting into your product that seems to be a downside.

No, I do not have any connection to Better Bottles whatsoever ... and yes, here is a link discussing their closure systems ...
BetterBottle (Better-Bottle) Fermentation Products &#8211; BetterBottle PET Carboys

As I do not bulk store wine for more than about 6 months or so, I use PETE carboys and glass carboys with just plain-old stoppers from the brewers/vintners supply.
If I bulk-stored longer, I&#8217;d be doing as I say above.
But I&#8217;m cheap ... er, frugal. And own a lot of bottles.

People want a one-stop-shopping, silver-bullet solution to things.
The real solution to avoiding spoilage - oxygen and otherwise - is largely all the things done during the production and handling before the wine gets sealed in the carboy or bottle.
A lot of things put together are what keeps wine during longer term storage.

In any regard, using a triangle-marked-7 carboy is a nonstarter for me. If ya don't use em, ya don't have to worry about oxygen permeability in them.

(Wow. Read all that. Better than Ambien?)
 
Find small plastic bottles, 2L size or so of different kinds of plastics and compare to a 1/2 gallon glass bottle, seal all of them hermetically for 3 months and later open and test carbonation level and for oxygen. It might take a couple years to notice much of a difference.

Well I'm specifically testing the oxygen permeability of the jugs mentioned in the first post during regular brewing conditions (aside from the contents of the jugs for reasons mentioned above). So sealing them and trying different types of plastic would not serve to accomplish the goals of this mini-study.


I would also seal the carboy with something other than an airlock, CO2 and oxygen can travel through the water in the airlock and the effect of this probably is much larger than travel through the plastic.

Well if I use an airlock for both then the amount of oxygen that enters via the airlock should be the same for both. And because I"m looking for the DIFFERENCE in the concentration between my plastic jugs and a glass jug then it follows that if they both get an equal amount entering from the airlock then that would be a non-difference. It shouldn't enter MORE in the plastic than the glass so any differences in oxygen contraction should be due to diffusion through the glass/plastic not due to the airlocks.
 
brazedowl said:
So to sum up... you don't use the jugs and don't care? Check :)

1. Try to take armchair quarterbacks with a grain of salt

2. Collect data

3. Repeat step #1

;-)
 
1. Try to take armchair quarterbacks with a grain of salt

@ geniz

Armchair quarterback?

Go to my profile and read some of my more technical posts.
When I write do I sound like I do not know what I'm talking about?

Why make a personal attack on me?

The point to testing the oxygen permeability is for storage purposes... no?
So I contributed some ideas on storage ... and the points why I don't use plastic non-PETE carboys.
 
Jacob_Marley said:
@ geniz

Armchair quarterback?

Go to my profile and read some of my more technical posts.
When I write do I sound like I do not know what I'm talking about?

Why make a personal attack on me?

The point to testing the oxygen permeability is for storage purposes... no? So I contributed some ideas on storage ... and the points why I don't use plastic non-PETE carboys.

Please don't take offense. I wasn't attacking you. I don't want this guy to not try his idea because of a bunch of people second guessing his idea.

Who knows, he might be completely wrong, but no one will know if he doesn't get some data. He might not do the perfect experiment first off, but hopefully what ever he finds will get him to refine his method.

I'm sure what ever he finds, there will be a whole lot of analysis

I'm just encouraging him to proceed and throw up some numbers

Again, it wasn't an attack to your post. I'm sure you know what you're talking about.

G
 
girls, girls... you are BOTH pretty. :)

awe shucks
th_fawning.gif
 
huesmann said:
Well, to be fair, unless you've actually performed the experiment the OP intends to, you kind of are an armchair QB.

Oh god. Please please don't start this up again
 
This has to be one of the most interesting threads I have read in a while! I can't wait to hear the results of the experiment. I doubt it'll kill my fear (however irrational it may be) of using plastic bottles, but it will still be interesting!

Good luck and keep us posted!
 
Well, to be fair, unless you've actually performed the experiment the OP intends to, you kind of are an armchair QB.

< Jacob re-enacts the missing-car-in-the-airport-parking-lot scene from Planes, Trains & Automobiles where Steve Martin loses it, stomps on his hat ... >
 
< Jacob re-enacts the missing-car-in-the-airport-parking-lot scene from Planes, Trains & Automobiles where Steve Martin loses it, stomps on his hat ... >

Love it! Not everyone can pull off an adult temper tantrum like Steve Martin!
 
hahaha Well I've been spending my two weeks of winter break trying to track down a glass carboy without buying one.

I may have to do a small scale version of a glass carboy with a 4L glass wine jug or something.
 
Per Raj Apte:

Tank Volume [L] O2 cc/L.year
Burgundy barrel 300 8.5
Rodenbach tank, wood, small 12,000 0.86
Rodenbach tank, wood, large 20,000 0.53
HDPE bucket 20 220
Homebrew barrel 40 23
Glass carboy, 30cm vinyl immersion tube 20 0.31
Glass carboy, silicone stopper 20 17
Glass carboy, wood stopper 20 0.10
 
I'd lend you one of mine, but Google maps says it is a 1700 mile drive to your location. The gas money alone would buy you 3 or 4 glass carboys! lol
 
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