A beer koozie is a fabric or foam device that is designed to insulate a beverage can

Beverage can

A beverage can is a tin can designed to hold a specific portion of a beverage. Beverage cans are made of tin-plated steel or aluminium.- History :...

 or bottle.

Overview

The beer koozie(koō-zie), coastie, cozy, coosie, coolie, hugger, or huggie, is a misnomer

Misnomer

A misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derive their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...

 since it is not always used for an alcoholic beverage. Other names are can cooler, "beer sleeve", stubby holder. The original pronunciation was "cozy" [koh-zee], but through a result of marketing names and misinformation "Koozie" [koo-zee] has become a common mispronunciation. It began as a marketing tool. The primary use of a beer koozie is to keep one's hand warm while keeping the beer cold. A secondary use of a beer koozie is to easily identify one's beverage from another. Many different companies have used the koozie as a promotional giveaway because it is not only inexpensive to manufacture, but its frequent use is more likely to bring the company's name to a household presence. Originally this logo or image was screen-printed on a round foam cylinder with a foam base (generally a hole is provided in the base to alleviate creation of a vacuum

Vacuum

In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...

). A koozie can be made from many materials like neoprene

Neoprene

Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene. Neoprene in general has good chemical stability, and maintains flexibility over a wide temperature range...

, polyester

Polyester

Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...

or open cell foam.

Materials and styles

The beer koozie has evolved in both material and style. The materials of which the beer koozie has been made include plain foam, neoprene and a foam variant of neoprene that replaces it with a cheaper and lighter weight closed cell foam. Some companies create koozies for 40 oz. bottles. The material used to construct the koozie is designed to insulate the warmth of the holding hand from the cool of the beverage.