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Thread: Thoughts on PET bottles?

  1. #1
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    Thoughts on PET bottles?

    I was reading this thread which seems to indicate very few mainstream breweries package in PET bottles, except for cheap brands, or in locations where glass is a problem.

    Is there any real concern with using PET packaging for beer, other than the general consumer perception?

    There are nice 500ml amber PET bottles available that I'd love to use, and I've been experimenting with them for a while now. I like the package from an aesthetic point of view. It feels good in the hands, to the point that you forget its a PET bottle. You can easily fill it isobarically and oxygen free.

    It's possible to create a PET bottle using combination of oxygen scavenger with an LC2 outer coating (a double liquid coating consisting of polyvinyl alcohol PVA and nano-varnish) that has extremely low oxygen permeability (less than 100 ppb over 6 months). There are other coating methods as well.

    There are many advantages to PET bottles, and in some ways they're better than aluminum cans. I think this is the ideal package for craft brewers.

    So what's the deal with PET bottles, and why aren't they used by mainstream breweries? In other words, are they used only for cheap beer because that's the general perception, or is there actual science involved?

    Regards,
    Mike Sharp

  2. #2
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    I'll bite. Beyond the stigma of a cheaper product, there are a number of concerns.

    You mention the "extremely low oxygen permeability", however 100 ppb over 6 months is way too much pickup for me. Since we are ideally hitting half that number or lower, you are still talking about a "fairly large" pickup of DO. Obviously both quotes offer some different perspectives. There are indeed layers and films that can be applied inside and out, but they still leave a desire for better results.

    PET is more prone to permeate gasses than an aluminum can or glass bottle. Oxygen scavenging lids/caps and liners can be used, but offer a temporary or limited amount of security against O2 (and are used on can & bottles, so no advantage there). PEN is a much better alternative, but the cost will go up and probably price you out of plastics. Light can be minimized by coatings but will not meet a can. PET will also bind with some aldehydes and can release them at a later point.

    Obviously you will have stigma from the BPA content of previous products and health concerns. Educating a consumer can be quite a difficult challenge. People still think vaccines give you autism.

    The largest opposition you are likely to find will be from environmentalists. Plastics are a huge problem for waste, despite being recyclable. Aluminum may be the only product which is economically beneficial to recycle, as it actually costs less to produce a new can from recycle over one from raw materials. Plastics (primarily because of their low cost) are often not recycled as often or as efficiently and generally end up contributing a lot to waste. Hard to get people into plastic bottles when they are banning the grocery store bags. Plastic water bottles are getting a lot of flak too.

    Sell me on the advantages of the PET and why/how its better than cans or bottles? - I'd be interested to take a fresh look. I get the weight, and color options but fail to see what advantage it provides to the product itself.

  3. #3
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    Don't do it.
    Brewmaster, Minocqua Brewing Company
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  4. #4
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    PET Bottles

    PET Bottles are widely used for beer in Japan by the big guys.

  5. #5
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    Quote Originally Posted by UnFermentable View Post
    I'll bite. Beyond the stigma of a cheaper product, there are a number of concerns.

    You mention the "extremely low oxygen permeability", however 100 ppb over 6 months is way too much pickup for me. Since we are ideally hitting half that number or lower, you are still talking about a "fairly large" pickup of DO. Obviously both quotes offer some different perspectives. There are indeed layers and films that can be applied inside and out, but they still leave a desire for better results.

    PET is more prone to permeate gasses than an aluminum can or glass bottle. Oxygen scavenging lids/caps and liners can be used, but offer a temporary or limited amount of security against O2 (and are used on can & bottles, so no advantage there). PEN is a much better alternative, but the cost will go up and probably price you out of plastics. Light can be minimized by coatings but will not meet a can. PET will also bind with some aldehydes and can release them at a later point.
    Thanks for your comments! I'll discuss the advantages (at least in my use case) of PET in a separate post, but I wanted to explain my thinking on the O2 permeability. If you're telling me that 100 ppb over 6 months is way too much, then what is your allowable pickup, and how do you know you're not exceeding it?

    The light bulb moment for me came when I was reading this study, where it described some of the difficulties with measuring oxygen ingress over time.

    1. Tests for O2 are destructive, so you can't directly measure the OTR (oxygen transmission rate) into a given package over time. Even if you assume all packages are identical, it takes a ridiculous number of packages to measure the rate over time, considering rate not constant. The study measured DO every 30 seconds for 6 months.
    2. Oxygen that does make it in will react with beer fairly quickly, making it hard to measure over time.


    They solved these problems by using a new non destructive optical-chemical test for DO, using a sensor placed inside the package, and read through the package wall via a fiber optic connection. They used deoxygenated carbonated water as the medium, and the bottles were filled in a purged glove box so they started out with zero O2.

    This led me to wonder if we (people brewing and packaging beer) really know how much oxygen ingress actually occurs in glass bottles or cans. We measure DO in our beer, and we know the DO levels will decrease if we don't measure it right away because the beer reacts with the oxygen. If we measure DO levels down the road, they're comfortingly low, which leads us to believe that very little oxygen is getting in. But we're measuring beer, and once we've packaged it, DO measurements way down the road are meaningless. If you take a glass bottle of beer and a PET bottle of beer, both will probably show near zero O2 at 6 months.

    According to Hach, a typical crown cap has an OTR of about 1-2 ppb per day. In three months, that can be 180 ppb total. Over a hypothetical 6 month shelf life, we're talking 360 ppb. I'm assuming the crown in this case doesn't include an oxygen scavenger, but even if it does, there is a limited capacity for the scavenger. At some point, a coated PET bottle looks remarkably similar to a glass bottle. So if we could keep the OTR under 0.5 ppb/day, the package should be acceptable for beer.

    As for cans, I haven't been able to find any research on what the OTR for a typical can is. If you've ever seen any, I'd love to hear about it. At first I was thinking the OTR would be nearly zero, but there's a seam between the body and the lid, and the can is lined with a polymer, so it's conceivable there is some oxygen ingress there. I don't know how you'd measure it, though, without modifying the can to make the measurement possible. In any case, I guess I'd concede that an aluminum can has near zero OTR.

    So the question in my mind is, if we assume 6 months is the desired shelf life for packaged beer, what is the actual amount of oxygen that can be allowed in over that time period?

    Regards,
    Mike Sharp
    Last edited by rdcpro; 12-03-2018 at 06:59 PM.

  6. #6
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    Quote Originally Posted by UnFermentable View Post
    The largest opposition you are likely to find will be from environmentalists. Plastics are a huge problem for waste, despite being recyclable. Aluminum may be the only product which is economically beneficial to recycle, as it actually costs less to produce a new can from recycle over one from raw materials. Plastics (primarily because of their low cost) are often not recycled as often or as efficiently and generally end up contributing a lot to waste. Hard to get people into plastic bottles when they are banning the grocery store bags. Plastic water bottles are getting a lot of flak too.
    Actually, I'm expecting the largest opposition to come from breweries! It seems like the very word "PET" causes tempers to rise.

    But environmental issues are always a hot button topic. Sure, aluminum cans are cheaper to recycle than to produce new, but the environmental impact from mining and refining bauxite into aluminum is REALLY bad.

    I get that PET has a bad rap in terms of recyclability, at least where post consumer PET is recycled into new beverage containers. But part of that is that the textile industry is willing to pay more, and when oil prices are down, so is the cost of virgin PET compared to rPET. Also, plastic that is recycled into food-contact applications has more rigorous requirements.

    The other part of that is that the recycling industry seems like it struggles to get any meaningful quantity of post consumer waste to actually be recycled. I think if most people were aware of how much of the material they put into their recycling bin each week actually ends up in landfills, there would be an outcry, but they would still probably buy water bottled in PET bottles.

    On the Eastern side of Washington state, it seems like there is pretty much zero recycling, so when comparing environmental impact of one type of package over the other, we should consider virgin containers--that is, cans or bottles (PET or glass) made from new material--because these are single use containers that don't enter the recycle stream. That puts aluminum out of the running, environmentally. At least, in my opinion.

    So I think most "problems" with recyclability of PET have more to do with how screwed up our recycling programs are, than the technical recyclability of it. I will admit that amber PET bottles are probably not going to get recycled in significant quantity until there are lots of them being used. There's a market for green resin and white resin, but probably not brown. So in places like Japan and Germany, it's less a problem than the USA.

    So the biggest environmental benefits of PET over aluminum are:

    1. PET bottles are re-usable. This is primarily an advantage for larger bottles, but I've been filling smaller 500 ml PET bottles with ginger ale for a while now as an experiment, and even at this size it's nice to be able to seal up the bottle and toss it back in the fridge.
    2. If virgin material is considered for containers that will not enter the recycling stream, aluminum has a poor track record.


    Regards,
    Mike Sharp

  7. #7
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    Quote Originally Posted by UnFermentable View Post
    Sell me on the advantages of the PET and why/how its better than cans or bottles? - I'd be interested to take a fresh look. I get the weight, and color options but fail to see what advantage it provides to the product itself.
    Finally, my last post! What are the benefits of PET? While I still like the idea of PET as a primary package for distribution, I'm primarily thinking of filling them at the point of sale, into "customer owned containers" --essentially growlers, based on the legal definition. So here's my list of benefits:

    • Lightweight compared to glass
    • Empty containers (before filling) are more durable than cans. Empty cans are pretty delicate. So, PET inventory is easier to deal with at the point of sale.
    • Easier to keep empty PET bottles sanitary. They're stored in boxes open end down, compared to cans which are stored open end up.
    • Easier to fill at the point of sale than either glass or cans/crowlers.
    • Easy to fill relatively oxygen free at the point of sale compared to cans (Crowlers)
    • Unbreakable compared to glass, which means both safer, as well as usable in situations where glass is not allowed.
    • Reusable compared to cans/crowlers. This benefit can't be understated--every growler that is refilled saves at least five 12 oz packages from waste and recycling streams.
    • Resealable. If I don't finish the container, I can screw the cap back on, and finish it later. Yes, it goes flat eventually…Still, people reseal them and drink them later.


    I agree with you that using PET for all of a brewery's packaging is probably risky. But I can see a good application of it in these cases:

    • Packages are filled at the point of sale. For e.g. growler sales on prem or at accounts that fill growlers, or at events like Farmer's Markets, music festivals, etc.
    • Packages that are destined for situations where glass is unacceptable, such as events, or near beaches, parks, etc.
    • Short run packaging, especially at very small breweries. The equipment it takes to isobarically fill PET bottles is pretty simple, compared to glass, and especially compared to short canning runs.



    Thanks again for your thoughts!

    Regards,
    Mike Sharp

  8. #8
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    Consumers drive this bus. Even though drinking from a can is effectively drinking from a plastic bag in an aluminium shell, market research shows little acceptance for a premium beer in a plastic bottle. In most first world beer markets, only utility/cheap/crap beer comes in plastic. Their consumers don't mind.

    BPA's are considered a real danger in virtually every first world nation. New generation 'plasticizers' are apparently even worse. You can pretend there is no issue, but there is. ...

    Pax.

    Liam
    Liam McKenna
    www.yellowbellybrewery.com

  9. #9
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    On the matter of Plastic

    Plastic in the hands of Humans is generally a bad idea as are a very many things that are Petrochemical based.
    Plastics have been applied and used way outside of their " Intelligent " range and with very bad consequences.
    I am getting very sick of Engineered products that used to be made fully out of metal, go into various stages of plastic. This is especially noted and especially stupid with respect to plumbing fixtures. Who are these OEMs trying to kid? People at large need to snap to the fact that Corporations by nature are Meta Destructive, and start
    1. Taking them to major task about their doings.
    2. Stop supporting them whenever possible.
    Warren Turner
    Industrial Engineering Technician
    HVACR-Electrical Systems Specialist
    Moab Brewery
    " No Cell Phone Zone."

  10. #10
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    Thanks for the feedback!

    One recurring theme I've seen is around the dangers of BPA. But PET is a polyester based plastic, and BPA isn't used in making PET. I realize that consumer perception is more important than reality, but BPA is used in polycarbonate plastics, vinyl ester and epoxy resins, softened PVC (recycling codes 3 and 7), and the lining of some canned food containers, but not PET.

    If the main objection to PET is consumer perception, that's one thing. I'm mostly interested in technical objections from the brewing industry. I'm interested in both reusable/refillable PET containers as a replacement for growlers, and "one way" bottles.

    Regards,
    Mike Sharp

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