The Great Debate- Plastic vs. Glass

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For the last 50 years or so, plastic has been steadily overtaking glass as the most common substrate for food packaging, and it’s estimated that plastic will surpass glass in beverage packaging by 2020. It’s not hard to see why… plastic containers are generally lighter, reducing transportation costs for the manufacturer– and reducing consumer trips to the car to retrieve the groceries. However, there remains a devoted market for glass with products like pickles and olives, beer, wine and spirits, not to mention artisan and boutique products of all kinds.

In some of these cases, glass is still simply the most practical choice. In the case of those pickles and olives, for instance. The pickling and curing liquids are very acidic, and during manufacturing the containers may need to be heated to ensure a vacuum seal. Plastic just does not hold up as well to those kind of needs.



It’s a similar story for beer. While glass (especially colored glass) provides your beer with protection from photo-oxidation, it also stands up much better than PET to the high-heat pasteurization process used by beer bottlers. In addition, glass’ impermeability and inertness ensure that beer retains its fizz and refreshing taste. You can find both wine and spirits in plastic bottles (or “boxed wine” with an interior plastic bladder), but the glass containers are generally seen as the more premium choice, housing a more premium product.

Glass is also used for non-food product packaging. It’s a standard in the cosmetic industry, as it offers safe containment with a luxury appearance. It also provides brand protection for the manufacturer; In an industry where knockoffs are rampant, the complexity of a high-end glass container is much more expensive to counterfeit than comparable plastic would be.

 
 

Pharmaceutical packaging has long held glass as the norm for its impermeability and inert protective qualities. As the only packaging material regarded by the FDA as “GRAS” (or Generally Recognized As Safe), glass is regularly used to contain liquid medications. Glass bottles, ampules and vials do not leach unwanted chemicals into intravenous drugs, although there was a rash of recalls in 2011 due to poorly made glass “de-laminating” and depositing glass particles into medications. In response to this, the US Pharmacopeia Convention (USP) augmented its standards for testing in 2012.

So, if glass is so awesome, why is plastic taking over the industry? The biggest factors come down to weight, expense, and fragility.

We’ll start with the simplest first – glass breaks. It breaks during manufacturing, shipping, and at your house. And when it does, it causes a huge mess and risks the safety of everyone in the area. New lightweighting techniques and surface treatments are increasing the toughness of glass packaging, but a 12-oz PET soda bottle will still feel safer next to the pool than your expensive beer bottle. Maybe not as much fun, but safer.

 
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Weight should also be considered. A 500mL glass bottle weighs about 400g, but a comparable 500mL PET bottle weighs about 10g. While that might add up to a little annoyance for the consumer, that 40 to 1 weight ratio is a very big problem for manufacturers and distributors. It means more wear and tear on packaging machinery, less efficient shipping and distribution, and, as a result, higher fuel costs and emission responsibility.

The other big factor is cost. Glass is more expensive to produce and more expensive to ship than plastic, and all those expenses will need to roll down to the consumer. Meaning, sometimes, that “premium” orange juice in the glass bottle is just… juice. You pay for the panache of the packaging.

Even the comparison of sustainability is a little muddy. Yes, Glass is 100% recyclable, all the time. But, at least in the US, glass recycling efforts are waning due to the increased cost of separating it from other recyclables and shipping that heavy bulk to the few recycling plants in the country. BUT just about every piece of glass packaging out there contains SOME percentage of recycled material. Plastic, on the other hand, is easier to recycle and uses less energy to complete the task. BUT plastic degrades with each run through the lifecycle; plastic packaging is “downcycled” into lower-grade carpet padding or plastic building materials. The plastics industry counts this as a plus – flexibility! The glass industry considers this a negative – glass will always be recycled as new glass.

So, there’s no 100% right answer. When making the choice between glass and plastic, you’ll need to assess a lot of factors. They are both great… and they both have their drawbacks to consider. Your product, your audience, and your budget will all play a part in the decision.

Head over to our Glass Packaging course to learn more!