How Caviar Works

The sturgeon is a lumbering, toothless fish with a decidedly prehistoric appearance whose eggs are harvested for caviar.

The sturgeon is sometimes called a "living fossil" because of its few adaptations through the millennia. The Acipenser family tree includes 27 sturgeon, although genetic markers have scientists disputing the exact number of distinct species. Some sturgeon, like the beluga, live a century or more and continue to grow -- in fact, one beluga reached a record 4,500 pounds and 28 feet long, which is about the size of a motorhome.

The eggs of each species of sturgeon, except the largely poisonous green sturgeon, can be used for caviar. However, only three sturgeon species -- the beluga, osetra and sevruga -- supply most of the world's caviar. These species live in the Caspian Sea, which is bordered by five nations including Iran, Kazakhstan and Russia. Other bodies of water producing significant amounts of caviar include the Black Sea and Sea of Azov.

Sturgeon are anadromous, which means they can live in both salt and fresh water. They prefer, however, to keep one fin in both worlds. Most live in tidal estuaries where salt and fresh waters collide, then swim in rivers to spawn. Sturgeon annually return to the same place to lay their eggs, and their predictable swim makes them easy targets. When caught, most sturgeon won't fight; they're simply resigned to their fate.

Caviar's premium price, coupled with demand, makes the sturgeon attractive to legal fisheries and poachers alike. Decades of overfishing mean fewer mature fish and scant opportunities to reproduce. This cycle is evident in the Caspian Sea's dwindling beluga population, which has dropped more than 90 percent [source: Science Daily].

Within the last 10 years, a number of efforts have attempted to assuage the sturgeon's collapse. Imported beluga caviar was banned in the United States, the beluga sturgeon was placed on the nation's endangered species list, and international coalitions pushed for stringently reduced fishing quotas. Few measures, however, held up to the continued demand for caviar.

As the caviar trifecta -- beluga, osetra and sevruga -- becomes a scarcity, other sources of roe become more acceptable. It's important to note, however, that caviar made from any other type of fish, such as salmon, is not considered "true" caviar and must contain the species identifier in its name. For example, a tin containing salmon roe must read "salmon caviar" not just "caviar."

Next, we'll discover why impeccable timing pays off when it comes to caviar.

When it comes to caviar, timing is everything. Three days before a female sturgeon is ready to spawn, her eggs are taut and flavorful. Taken too early, the eggs are gooey with fat and won't offer a trademark "pop" when eaten. Taken too late, and they'll be a milky, mushy mess.

It seems the freshest caviar is plucked from a live fish, so sturgeon are often stunned by a bonk to the head and then slit open while still alive. Once the ovaries are removed, they, too, are emptied of their contents. Although the process of harvesting roe may seem cruel, there's been no major public outcry over its practice.

Harvesting eggs is a delicate process often done manually because roe is fragile and easily damaged. The roe sacks, or ovaries, are opened and rubbed across mesh screens using gentle pressure from the palm of the hand -- this action separates the eggs from the membrane and they drop through the screen into a shallow tub. The eggs are then rinsed with cold water and salted. After several hours, the resulting brine is drained and the roe, which is now caviar, is packed in containers with airtight lids -- fresh caviar will keep for two to four weeks.

The term for lightly salted caviar is "malossol," and it has a salt content of less than 5 percent. Most modern malossol caviars, however, contain less than 3 percent salt. Caviar with a salt content up to 8 percent is aptly named "salted caviar" or "semi-preserved caviar." Although still fresh, this caviar sacrifices taste for longer shelf life. Lesser grades of caviar with up to 10 percent salt are compressed into jam-like cakes with concentrated flavor, called "payusnaya," that will keep for three months.

Some fresh caviar is pasteurized. To do so, small vacuum-packed jars of caviar are immersed in hot water for several minutes. Pasteurization decreases the risks of encountering a food-borne pathogen, such as Listeria, which can be especially harmful to pregnant women. It also creates a shelf-stable product that can withstand a year of unrefrigerated storage and shipment.

Fresh, unpasteurized caviar, however, must remain at a constant, chilled temperature when shipped. A high-maintenance delicacy, caviar also requires frequent attention during transport -- it has to be turned often so the fat evenly coats each egg.

If caviar seems like a simple affair, keep reading -- the subtleties may surprise you.

Caviar holds a fascination for gourmands in large part because of the subtle variances in types of caviar. Like grapes used in wine making, the essence of caviar is influenced by many factors as the eggs ripen.

The beluga sturgeon, large and increasingly rare, produces large caviar that is light to dark gray in color. The buttery taste is less intense than fine-grained caviar, and the coarse row offers a delicate texture. In contrast, the eggs of the small sevruga sturgeon are blackish green with a concentrated flavor. The medium-sized osetra sturgeon produces caviar that is deeply golden to dark brown in color and features a nutty taste.

For each type of sturgeon, there are two grades of caviar. Grade 1 caviar features firm, large, intact eggs, delicately taut with fine color and flavor. Grade 2 caviar is still good, and most would be happy to sample it; however, it's simply not as beautiful to the eye or pleasing to the palate as Grade 1. Additional color criteria may be used as well. For beluga caviar, "000" indicates silver or light gray, "00" means medium gray and "0" is gray -- light colors are prized more than dark colors but taste the same.

Damaged roe won't make the grade at all, but this milky mixture can still be eaten. It is heated, placed in fabric pouches and pressed to remove excess moisture, salt and oil. This pressed caviar contains, per ounce, four times the roe of fresh caviar and has a deeply intense flavor.

Although beluga caviar is the most sought-after, costing about $400 for two ounces, it isn't necessarily the pinnacle of the caviar-lover's quest. The rarest, and therefore most expensive, kind of caviar is golden caviar. Also known as "royal caviar" it is thought to be eggs that would produce albino osetra. This caviar, a pale daffodil color, is found in only one in 1,000 osetra sturgeon.

Russian and Iranian caviar is popular the world over, but wild-caught American caviar -- from the Atlantic sturgeon and white sturgeon -- is gaining a foothold in the global caviar trade.

Wondering if you need to eat caviar with your pinky finger aloft? We'll share a few well-mannered tips on the next page.

Caviar, for those who can hold their appetites in check, is a delicate enjoyment meant more for the palate than the stomach. It's considered poor manners to eat more than just a couple of spoonfuls in the company of others. Fortunately, when it comes to nutritional content, there's a lot packed into each bite -- just one spoonful of caviar will supply your daily requirement of Vitamin B12.

Caviar also is a high-protein food with less than three grams fat in each tablespoon. It's an excellent source of amino acids, omega-3s, vitamin D, iron, magnesium and selenium. However, caviar is high in both sodium and cholesterol, and, there are food-borne illness risks inherent with consuming raw foods. Pregnant women in particular should avoid eating caviar that isn't pasteurized because of the pathogen Listeria.

Whether pasteurized or fresh, caviar should be chilled when served. For those who like to sup their caviar with traditional savoir-faire, caviar should be oh-so-carefully ladled into a small dish nestled on a bed of crushed ice. If the caviar's brand is brag-worthy, its lid -- with the name clearly showing -- may be displayed nearby.

For purists, caviar is best eaten solo. Using a specially designed spoon made of bone, crystal or mother-of-pearl (metal spoons are believed to alter caviar's taste), the caviar berries are gently lifted from their dish in a vertical motion and savored without interruption from other ingredients.

Caviar is also often served with crisp, freshly buttered toast points. The buttered triangles, topped with salty caviar and a dollop of crème fraiche, create a festival of flavors -- the taste is at once salty and sweet, yet tangy and delicate.

Blini, thin buckwheat pancakes of Russian origin, are topped with a spoonful of caviar and a dot of sour cream and then loosely rolled into a tube. In some Eastern European countries, caviar is eaten with small steamed potatoes. And, to stretch its quantities, restaurants often serve caviar with chopped red onions, thin slivers of hard-boiled eggs and sour cream, all garnished with parsley.

Whether fresh or pasteurized, caviar leftovers will keep only for a day or two. In the meantime, place the caviar into its original container, cover it tightly with plastic wrap and then replace the lid. Place it in the coldest part of your refrigerator, but pack the caviar container in ice if the fridge doesn't maintain a temperature below 32 degrees.

As caviar-lovers will attest, however, the best possible way to store uneaten caviar is by practicing strict avoidance. In other words, buy as much as you need for the moment and indulge until the last voluptuous orb has been devoured -- preferably off the back of your hand where the warmth liberates each pearl's fragrance. After all, caviar's historical mystique is as satisfying to the mouth as it is to the mind.

To learn more about caviar, see the links on the following page.