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Name: Beth
Status: other
Grade: other
Location: WA



Question:
I was just wondering: Besides cost, how do manufacturers end up with the beverage package of their final choice as either; glass, plastic, or aluminum. For example, some milk is sold in plastic while others are sold in paper boxes. With beverages, sports drinks are mostly found in plastic (not aluminum), and then you have beer that is only sold in aluminum and glass. Why is this?


Replies:
There are tons of factors to consider, and ultimately every product has a unique set of requirements and goals that lead to the type of packaging used. In many cases, there is no ‘perfect’ package, so multiple options may exist.

1. Cost - You are right, cost is a big factor.

2. Use - How the container is to be used is another factor. For example, an athlete might want to have a reclosable container, such as twist-top plastic instead of a can or a carton.

3. Breakability - That same athlete might want a non-breakable container, whereas a wine drinker might not be so concerned.

4. Gas permeability - A big factor that is more science-related is gas permeability ­ that means how much gas can migrate through the container. Glass and aluminum are great for carbonated beverages because they block gas from moving in or out. Before modern PTFE (a kind of plastic) bottles, carbonated beverages were limited to glass and aluminum because the CO2 could leach out of PVC and PE (two older types of plastic) bottles, leaving the beverage flat.

a. In wine, corks let in just a little air over a long period of time, helping wines to age gracefully over years of storage, but corks are not supposed to let water escape or enter (though they do sometimes, and now you see high quality wines using synthetic corks or screw tops).

b. Screw caps for beer let in/out more gas too -- so lower quality beers might use twist-off caps, but higher quality beers use standard tops.

c. Metalized plastic (such as are used inside boxed wines) reduces gas permeation, blocks light, and eliminates the air space in the container ­ more and more often, high quality wines are being packages in boxes)

5. Light - Light penetration can affect beverage quality in milk, beer, and wine (hence paper cartons, colored glass, metalized plastic, etc.).

6. Sterility ­ Some drinks are prone to bacterial or fungal growth. Some drinks are pasteurized (milk) or heat sterilized (juice, beer) to give them longer shelf life. Aluminum containers are very easy to sterilize. Glass can be heated, but the pressure buildup (gases expand when heated) can break glass. Plastics typically are not compatible with high temperatures.

7. Chemistry ­ for example, aluminum can be eaten away by acid ­ for this reason juices are typically packed in glass or plastic. Glass and plastics are typically pretty chemically inert. Modern cans can be lined with a liner to protect the can, or some juices can be made to be less acidic.

8. Flavor - Plastic containers also affect flavor strongly -- not only do flavors leach out of the plastic, but some components of beverages will leach into plastic as well (the oils that give orange juice its fresh flavor can bind tightly to plastic). Drinks that are more delicate in flavor (like wines) would be less suited to plastic containers than beverages where flavor is less important (soft drinks, inexpensive beers).

9. Temperature - a hot coffee or cold drink might be served in an insulating container.

10.Tradition/history - Tradition plays a huge role -- think of how the characteristic shapes and glass colors of wine bottles tell you the kind of wine they contain.

11.Marketing - Marketing is always a factor ­

a. Color - many beverage makers want you to see their color (sports drinks again come to mind -- color indicates flavor).

b. Shape - Many beverages use uniquely shaped bottles to identify them (coke bottles come to mind, as does red stripe beer).

c. Brand information and/or nutritional data - any container must have some means of labeling, and other containers have vivid art on them (wine/beer labels, orange trees on juice containers, etc.).

12. Recyclability and other environmental friendliness considerations are also factors.

Hope this helps,
Burr Zimmerman


The selection of packaging is a complex process that depends upon many, often opposing, variables. Shelf life, air permeability (especially oxygen), sensitivity to light, storage temperature, reactivity the product and container, flavor changes -- it is a long list. An example is beer. Yes, it is sold in aluminum cans but the beer does not come into contact with the aluminum because the inside of the can and lid is sprayed with a coating of epoxy, and it is this coating that actually comes into contact with the beer. Another very complex packaging material is potato chips. There are up to six layers in a bag -- some functional, others decorative. Packaging often costs much more than the product it contains.

Vince Calder



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