Popcorn bag

A popcorn bag can refer to either the bag in which popcorn kernels that have been popped in heated oil are served, or to a specially-designed, microwavable bag that contains the popcorn, oil, and seasoning.

Microwave popcorn bags

The bag is typically partially folded when it is placed in a microwave, and inflates as a result of steam pressure from the heated kernels.

The design of a microwave popcorn bag is specifically keyed to avoid popped kernel scorching, an undesirable effect that takes place when popped kernels are heated above 210° Celsius. [http://www.wipo.int/cgi-pct/guest/getbykey5?KEY=01/53167.010726&ELEMENT_SET=DECL]

A susceptor, usually a metallised film laminated onto the paper of the bag, absorbs microwaves and concentrates heat at the film interface, thus ensuring a heat distribution focused on the hard-to-heat flavor coating so that the unpopped kernels are evenly coated prior to popping, thereby ensuring even flavor throughout the product.

An early susceptor popcorn bag design was patented by the American company General Mills in 1981 (US Patent #4,267,420).

Modern design issues

One danger of the microwave popcorn bag is that after one use the susceptor typically "will lose its ability to safely react to microwave energy. If it is reheated, the changes in the susceptor can cause it to burn." [http://aginfo.psu.edu/News/may00/microwave.html]

In 2006, concerns were raised about the levels of perfluorooctanoic acid (PFOA, a chemical related to Teflon) in popcorn bags. The high temperatures used in popping popcorn may facilitate the transfer of the chemical, which is carcinogenic in lab animals, into the popcorn oil. DuPont has agreed to eliminate almost all use of the chemical by 2015. [http://www.foodnavigator-usa.com/news/ng.asp?n=65503-dupont-chemical-pfoa]

Additionally, the artificial butter smell used in many brands of microwave popcorn has been linked with the obstructive lung disease, bronchiolitis obliterans, sometimes referred to as "popcorn lung." [Citation
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title = Popcorn May Cause Lung Disease
newspaper = ABC News
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date = Sept. 6, 2007
url = http://abcnews.go.com/GMA/OnCall/Story?id=3565670&page=1]

Home-made alternatives

Concerned with the above issues people have been making their own popcorn bags from simple paper bags [http://www.instructables.com/id/Microwave-Popcorn:-Home-made,-cheap-and-easy/] or popping the popcorn in the microwave in other containers including large glass bowls with a heavy, but not airtight glass lids. Both of these home made approaches remove the threat of exposure to artificial flavoring and PFOA, but have a chance of leaving some corn kernels unpopped due to randomness of the microwave radiation distribution in a microwave.

erving-style popcorn bags

The serving-style of popcorn bags range in size from single-serving to very large, depending on the hunger of the patron or the size of his or her party. They are often sold at movie theaters, concerts, sporting events, fairs, and festivals in North America. These bags are usually made from thin paper (although larger bags are often plastic-based) and feature a distinctive jagged-cut top.

References

* [http://mailer.uwf.edu/listserv/wa.exe?A2=ind9803&L=chemed-l&D=1&F=&S=&P=92646 Microwave susceptors in popcorn bags]
* [http://www.wipo.int/cgi-pct/guest/getbykey5?KEY=01/53167.010726&ELEMENT_SET=DECL Alternative popcorn bag patent]
* [http://www.ll.georgetown.edu/federal/judicial/fed/opinions/96opinions/96-1238.html Microwave popcorn patent dispute between General Mills and Hunt-Wesson]
* [http://aginfo.psu.edu/News/may00/microwave.html Dangers of reheating microwave popcorn bags]