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Glass Packaging a Clear Choice
Products Packaged in Glass Look Better, Taste Better and are the Purest They Possibly Can Be
by Mike Lonsway
For generations, glass packaging has been trusted to store food, beverages and medicines. Glass has the staying power as a pure, sustainable package that’s healthy for the consumer and the environment. Made from natural raw materials – sand, soda ash and limestone – glass is impermeable and nonporous, which protects its contents from degradation and tampering. In addition, glass is chemically inert, which guards contents from moisture and oxygen, and ensures that the freshness and flavor of its contents – along with the product’s shelf life – are preserved.
Glass is the only packaging material generally recognized as safe (GRAS) by FDA. With the GRAS classification, glass containers require no leaching or extraction testing. The FDA requires all other packaging options to predict the amount of migrating foreign substances that will be consumed and sets limits on the amount consumed when products are packaged in anything other than glass.
A recent national consumer survey conducted by the Glass Packaging Institute shows that while consumers purchase products in a variety of packaging materials, they prefer glass for its quality, purity, taste, product protection and shelf life.
- 82 percent of respondents say glass keeps food in its healthiest form;
- 78 percent of respondents say glass preserves the purity of its contents;
- 75 percent of respondents say glass preserves the flavor of its contents;
- 73 percent of respondents say glass preserves the quality of the product;
- 62 percent of respondents say glass increases the shelf life of the product.
Consumers of organic products rate glass even higher—6 to 8 percent higher—in the areas of environmental safety, true flavor, best shelf life, healthiest form, best purity and best quality.
Because glass is chemically inert, its contents have a long shelf life without the risk of cross-contamination, and it is free of the health concerns now prevalent with competing types of containers.
An added benefit of glass is its transparency. Consumers can see and trust the quality of the product being purchased. When purchasing a product packaged in glass, consumers place a higher value on products they can inspect.
Glass is the only true “cradle-to-cradle” or endlessly recyclable package. Once glass is sorted, it remains the most easily processed and most readily recycled container. Even when recycled again and again, the quality, purity and clarity of glass does not deteriorate. A bottle can go from a curbside recycling box, through the recycling stream and re-made into a new bottle and on a store shelf in as little as 30 days. It is possible to have new bottles made of 100 percent recycled glass or cullet. The main factor preventing glass manufacturers from producing 100 percent recycled containers is the quality and availability of cullet.
In the United States, O-I operations average a 35 percent cullet usage rate, hindered only by recycling rates and cullet availability in North America. But the O-I plant in Rheims, France, uses up to 90 percent cullet in glass manufacturing because of the area’s high quality recovery and recycling methods.
The key benefit of using cullet in the manufacturing process is reducing nitrogen oxide emissions and energy consumption. For every 10 percent of cullet used, particulates are reduced by 8 percent, nitrogen oxide by 4 percent and sulfur oxides by 10 percent. So for every six tons of cullet used, one ton of carbon dioxide emission is reduced. And, for every 10 percent of cullet used in the glass manufacturing process there is the potential of a 2.5 percent energy savings.
Even though the raw materials used to make glass are abundant, for every ton of cullet used in manufacturing, more than a ton of raw materials are saved, including:
- 1,300 pounds of sand;
- 410 pounds of soda ash;
- 380 pounds of limestone;
- 160 pounds of feldspar.
A Danish Environmental Protection Agency study conducted in 2000 and revised in 2001 concluded that kilogram for kilogram; glass is the most environmentally friendly package across the board when considering greenhouse effects, acidification and eutrophication. The study concluded glass is the life-cycle standard by which all other packaging should be measured.
Light-weighting plays an important role in making a sustainable product because energy consumption during the manufacturing process is proportional to the weight of the container. For every gram of glass saved in light-weighting containers, there are cost savings, which allows food or beverage manufacturers to put more resources into new product development and innovation.
What has had the most impact on light-weighting glass containers is the consistency developed through the manufacturing process. In general, the press-and-blow manufacturing method facilitates better glass distribution in the mold, potentially reducing the container’s weight. For example, gob weights are controlled within a few one hundredths of an ounce during production. It is estimated that 20 to 30 percent of advancements in light-weighting have come from improving the manufacturing process through consistency and inspection systems.
Additionally, glass manufacturers are able to model and simulate the forming process of the container using a computer program. What is critical to glass manufacturing is getting the correct amount of glass in the appropriate position. The computer program used during design development allows the engineers to make the most efficient container with both the blow and blow and press and blow methods.
Having a container with the glass distributed strategically and consistently has led to a lighter, yet stronger container. And, future developments in strengthening glass containers include coatings and surface treatments. In its most pristine form, glass is stronger than steel. However, glass is brittle and surface abrasion can affect its strength. So, current areas of focus are coatings and surface treatments to protect and prolong the inherent strength of glass.
Glass packaging will continue to be a packaging choice for generations to come. Consumers receive a quality product that’s good for them and the environment, and food and beverage manufacturers keep their product fresh and attractive in a package consumers prefer. Products packaged in glass look better, taste better and are the purest they possibly can be.
Mike Lonsway is director of New Product Development for Glass Containers North America. Reach him at 567-336-5000 or Michael.Lonsway@oi.com.