Fresh caviar is rather a misnomer, since it is aged in the brine for one to four weeks or even longer. Roe fresh from the fish has virtually no flavor whatsoever and must be brined for not only flavor but preservation.
How to buy caviar
Sturgeon. The caviar is soft, clear, and glossy, with large, pea-sized eggs. They range in color from light silver-gray to black and have a creamy, almost buttery taste. The eggs have a prominent dark spot called an "eye" which is the actual egg itself. The surrounding gel is the egg sac. It is considered the highest premium grade available.
Sturgeon. Medium-sized gray to brown eggs with a flavor almost nutty, considered second in quality to beluga.
Sturgeon. Smaller eggs than osetra, grayish in color, strongest in flavor of the imports. Experts find sevruga to have a saltier flavor because the eggs are smaller. Although they are exposed to the same percentage salty brine as beluga, one gets more eggs in a bite of sevruga than beluga simply due to the size difference of the eggs, hence more of a salty flavor.
Sturgeon. Small golden eggs which were once considered the finest caviar available and reserved for the highest royalty in the lands. This variety is virtually extinct, so don't expect to find any on the market, even if you can afford it.
Lumpfish. Popular and much less expensive, this roe has tiny eggs, usually dyed black or red.
Paddlefish. Also known as American caviar from the roe of a Mississippi paddlefish, a distant cousin of sturgeon. In 1998, the U.S. government ruled that the paddlefish is a sturgeon for food purposes. The roe is small to medium in size, varying shades of gray in color, and have an earthy flavor that some refer to as slightly "muddy."
Whitefish. The whitefish is found in the Great Lakes region as well as other northern countries. Also known as Golden Whitefish caviar, the roe has small, golden yellow eggs and a less complex flavor making them culinarily versatile.
Salmon or Red caviar
Salmon. The eggs are of medium size, light orange to deep red in color. Salmon caviar is the most often recommended substitute for the more expensive sturgeon varieties.
Carp. Roe from the carp, orange in color. It's often sold smoked.
Rainbow trout. The roe is orange and smaller than salmon roe. The flavor is less salty than sturgeon and mild in flavor. Farming makes it one of the least expensive options yet yields great flavor value.
Malossol: The term malossol on the label is not a type of caviar, but a Russian term (literal translation "little salt"), meaning the fish roe was good enough to be processed using a minimal amount of salt, typically five percent of salt per weight. Most experts agree, the less salt, the better the caviar, but less salt makes it highly perishable and thus more expensive.
Pasteurized: The roe is partially cooked as a preservative measure, so it has a longer life. The pasteurization causes a slight change in texture, a bit more firm. Some pasteurized and/or jarred caviar may or may not need refrigeration. Check the label to be sure.
Pressed: Also known as payusnaya and pajusnaya. You can bet that not all eggs that pass through the sieving process squeeze through intact, and they are certainly not tossed out. The result of broken, weak, or damaged eggs is pressed caviar, which is specially treated, salted, and pressed. It is often a combination of several types of roe and has a jam-like consistency. Although it cannot compare to the real thing, it is still a viable solution for recipes, having a richer, more intense caviar flavor. It is often preferred by home chefs looking for that caviar touch in less expensive dishes.