I apologize for any confusion which may have arisen due to the error which I committed somewhere between my eyes and my fingers, most likely in the cranial cavity, lol.
For oxygen diffusivity, PET is one of the better polymers between 1-2 orders of magnitude lower than polypropylene, HDPE, polycarbonate. Not quite as good as unplasticized, unfilled PVC. Not nearly as good as PVA.
I finally found an article which has PET and PVA (in this case EVOH, ethylvinyl alcohol, one of the PVA family of polymers).
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EVOH is almost two orders of magnitude lower oxygen diffusivity than PET, with the caveat that the EVOH would have to be a buried layer, not directly in contact with liquid. EVOH in contact with liquid is no better than PET for oxygen diffusion.
I totally agree with you Gene. Facts should be put on the table. Better bottle say their patent is pending. Hopefully someone with enough know how amongst us will be able to read that patent app and make sense of whether BB is a step forward or not. If their patent is in process then they have no worries or fears of anyone stealing their idea. My practical nature hopes it is not all shill, since BB is ridiculously lighter than glass!!
Sean
gene wrote:
chemist but appreciated! It does indeed
Better-Bottle.com website does suggest, albeit a little
I wish they'd provide statistics too. Hi Gene, and thanks for the info! The last bit of information I got from Better Bottle regarding the material used for hte Better Bottles was this: " There are many formulations for PET as used in products. Pure PET is a much better barrier than most other plastics; however, with the addition of certain copolymers and the right stretching, it becomes much more impermeable. We use a copolymer that has an extremely low permeability, and we are working to make formulation that have such low permeability that they can be used to produce 750 ml, re-usable wine and beer bottles to replace glass. Crystallized PET is what we use for our fittings. " I did ask in the first instance for stats, but they obviously don't give those out.
I made a cranial processing error when writing the first sentence below. I looked at the oxygen solubility column rather than the oxygen diffusivity column. OOPS.
PET is betwen one and two orders of magnitude lower oxygen diffusivity than polycarbonate, HDPE and polypropylene. But PET still at least 100X (could be up to 1000x) worse than in glass containers.
In winemaking terms, white wines stored in sealed glass carboys might be expected to last 2 to 3 times as long as in virgin PET containers, if there are no other air leaks past the stopper. For red wines, PET carboys might be a good thing. PET has slower micro-oxidation rate than HDPE, which is used by some aussie wineries for reds aging. For white wines, you don't want any micro-oxidation.
Please note that PET is on the order of 20 times higher oxygen diffusivity compared to EVOH (ethylvinyl alcohol, a member of the polyvinyl alcohol family). However, there is a caveat for EVOH... it's oxygen barrier properties are no better than PET when in direct contact with water, so EVOH must be a buried layer in a polymer 'sandwich' to get benefit of it's better oxygen barrier properties.
I'm having trouble finding the oxygen diffusivity for glass, to compare against all polymers. Dang, I wish my materials science reference books weren't in storage. If I recall correctly, glass is between 2 and 4 orders of magnitude better than polymers for oxygen diffusivity (100 to
10,000 times better) for the same thickness. Now, as we all know, glass carboys are thicker, so the glass carboy is hella lower total oxygen diffusion rate than any plastic carboy. The oxygen getting into wine in a glass carboy, for all practical purposes, only comes through the airlock stopper or leaks between the stopper and the glass.
Because they are in production business in which aging does not add enough to the bottom line to justify it. It's similar to American 'Big Three' Brewers who can sell 'swill' as fast as they can make it. Why bother with improving product?
Take a look at the year on 'Two Buck Chuck'.
It's still PET. Miller is bottling beer in plastic bottles ans assert that the shelf life is six months.
There is nothing wrong with Pet soda bottles for storing wine, mead, or beer you intend to drink in the next 30 days. Is there any evidence that a Better Bottle has an oxygen barrier that will hold up for one to three years? I'd like to read it.
SInce the closest place to get Three Buck Chuck that I know for certain (ie there could be closer) is a full days drive in the summer, I won't be doing that anytime soon.
It's 3 bucks here now too and it's not that special. It's ok wine and you get a bottle to reuse.
As to the long term storage if we had a local supplier I would try one. I looked them up and they aren't much more than glass. I rarely go over a year in glass, I'm not making artisan wine.
It made me smile when I saw her name Gene I must admit ;)
I must admit I will be / am happy to make wine as good as commercial wineries so it doesn't pain me if I can't use the BB for reliable aging beyond a few months. I'll no doubt realise my ignorance when I taste a glass bulk-aged wine in later life.
I agree with the general sentiment. "Stats out for the lads." Otherwise we are all just speculating on the minutae on the assumption that they are being honest/dishonest with their advertising claims.
It seems unlikely that they / their supplier have never measured the permeability of their product. The spiral of silence suggests that the figures don't look as good on paper as they'd like them too. It's a reasonable assumption. As to whether they feel it looks bad or will make people think it is bad (remembering how permeable barrels are) I suppose that's another opinion with no substantiation.
Thanks for posting this thread though, it's useful stuff...
Here in North Carolina, $2 buck Chuck is $2.99 (Trader Joe's just opened in Cary, a suburb of Raleigh). I agree, it's an OK wine. I have used it to blend and that works well. I had a Shiraz that was kinda weak, so I added 18% Two Buck Chuck's Cab Sauv. And now it's real nice. It took a week after blending to clear up. But I am really liking this blend. And I got some bottles added to my inventory. smile.
As far as Better Bottles - I have one, use it more often than my heavy glass ones. I did have an oxidized wine from bulk aging, and I had it in the BB for 5 months. Not sure it was the bottle or something I did, though. So this is anecdotal and fyi. It drank OK early, but now I'm stuck with 9 bottles of vinegar.
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