Head cheese. (Back to Basics).

Watch it wiggle, see it jiggle." Most of us can hum the jingle on demand, depending on our generation. Whichever version you prefer, gelatin or gelatine conjures up childhood memories for most of us. Who could forget John Belushi's gluttonous slurp of gelatin in Animal House? With many names--Jell-O, aspic, jelly, gelee and so on--gelatin has an identity of its own. Nostalgically, it is most often identified as the jiggly-wiggly, colorful, sweet and savory mass that can be molded into just about any shape or flavor.

In actuality, gelatin is a by-product derived from the skin, connective tissue, and bones of animals. In its pure form, gelatin has no flavor and is considered completely neutral. Commercial gelatin is obtained from the: skin of pigs and cattle. Previous concerns about links to Bovine Spongiform Encephalopathy, better known as mad cow disease, have made its use controversial. Although it comes from animals, the FDA does not consider gelatin a meat product. While it is clearly animal based, the by-product is so filtered and purified that most vegetarians and even kosher practitioners consume it.

Commercial gelatin is available in leaves (or sheets) and powdered forms. Most pros are more familiar with leaf or sheet gelatin simply because sheets are physically easier to count as opposed to measuring powder using spoons. There are several varieties of sheet gelatin available based on the weight of each type of leaf. For domestic use, the powdered form, sold in pre-portioned packets, remains popular.

Not only does sheet gelatin come in different varieties with differing weights respectively, but it also is available in different sized sheets, adding to the confusion. This inconsistency could potentially alter a recipe with disastrous results. For accuracy, gelatin should be measured by weight.

With collagen as the base, gelatin possesses a natural ability to jell but requires manipulation and preparation in its commercial form. In either leaf or powder form, gelatin needs to be softened in a cold liquid, usually for a few minutes. This is called "blooming." The bloomed gelatin needs to absorb liquid and then is melted over low heat before it can then be added to a tempered mixture. Gelatinized liquid universally sets at 68 degrees and melts at 86 degrees. Homogenization and even distribution is crucial, as unwanted graininess and lumps can result. When cooled, the product congeals and therefore, the form and texture of anything made with gelatin can be imaginatively altered.

There are certain foods that will not allow gelatin to congeal. Fresh figs, pineapples, papayas, guavas, passion fruit, and mangoes contain an enzyme called protease, which breaks clown the protein in gelatin and prevents the liquid from setting. Cooking the fruit will destroy this enzyme but could alter the flavor. Thanks to pasteurization, most frozen fruit purees are protease-free, and can be used with gelatin, eliminating the cooking stage.

Most commercial forms of gelatin are pork and cattle based. However, all animals contain some kind of collagen. Chicken or fish stock will jell when chilled but will not have the same firmness as those that are made using pork or beef. They also do not maintain their solid form in warm temperatures.

While gelatin appears more commonly as a sweet dish in North America, savory gelatin dishes have long been a standard in Europe. The Italians have osso bucco with its famed marrow center: In France, tete de veau, consomme en gelee, and the like are considered classics. The English love their aspic and jelly, while the Chinese have been eating grass jelly as a health food for ages.

A gelatinous dish can also be any slow cooked meat combination, including bones, skin, and/or connective tissue to create the necessary ingredient, collagen. This ingredient will naturally provide a texture that coats the mouth and provides richness to the sauce or liquid. In addition, chefs have traditionally used gelatin to help display and preserve their work-intense dishes for intricate presentations in classical food competitions and salons, particularly in Europe.

People who have eaten pork trotters or any other collagen-rich cut of meat may have noticed an enhanced shininess to their hair, stronger nails, or less achy joints. Natural collagen is said to be a protein-builder in the human body. Gelatin has long been sold in pill form as a supplement. It's also reputed, but not proven, to help build up cartilage in sore joints, but it cannot replace missing or damaged cartilage.

Some alternatives which produce results similar to gelatin are agar-agar, carrageenan, tapioca, sago, guar gum, pectin, and rennet. All thickening agents, most are either vegetable or plant based and, like pectin, occur naturally in some foods. The exception, rennet, is an animal based coagulant often used in cheese-making. However, while some of these ingredients may come close, none can achieve the viscous result unique to gelatin.

Often thought of as institutional food, , gelatin is everywhere. Its ubiquitous presence in commercial establishments and in most foods we buy off the shelf is remarkable. Who hasn't chewed on gummy bears or gnawed on licorice candy? They all contain gelatin, as most soft or chewy textured processed commercial foods. Ice creams, gum, marshmallows--the list is endless!

While we might reject some of these "processed" foods , gelatin is still a magical substance. In our kitchens, it makes our mousse stand tall, adds sparkle to our garnish, and helps our cream and custard hold its shape. And you thought it was just something you molded! Gelatin seems to have been around all our lives, in health and in sickness. The time has come to see through" its properties and possibilities more clearly than ever.