Not unlike a diamond, not all caviars taste and cost the same; and therefore caviar eggs are scrutinized based on a number of factors. There is a logical standard that is followed (known as grades) and caviars (both sturgeon-based and caviar substitutes) undergo a significant amount of analysis to define just how good it is. Several aspects will determine where a particular caviar falls on the rating scale, and thereby determine how delicious, and expensive it will be.
The following list symbolizes the factors that regulate the rating of a certain caviar.
Clarity: Like an exceptional diamond, the egg’s shiny outer coating determines the freshness of the caviar. Eggs should be shiny and somewhat transparent, as dull, oily, or murky looking eggs tend to be a sign of improper storage or preservation.
Color: The color of the eggs or grains is the primary basis to the overall caviar quality. The color of the eggs are largely dependent upon the age of the fish, and thereofe the color of the eggs will vary with age. For example, in Osetra caviars, as the sturgeon matures the color of the eggs will diminish from gray and turn golden or golden-brown in color (also called Imperial or Royal caviar). Color is rated as follows: 000 for light caviar (for example grey), 00 for medium, 0 for dark (for example black).
Consistency: Not unlike a good strand of pearls, the complete consistency of the caviar’s appearance should be uniform throughout. In other words, all of the eggs should be identical based on factors such as size, color, etc. to all of the other eggs in the caviar group.
Fragrance: The freshest caviar should have a “fresh ocean scent” which echoes the overall freshness of the eggs themselves- fresh fish=fresh scent. Of course the fragrance reflects the freshness of the eggs at the time of processing, and the final scent could be an indication of the preservation process (salting, brining) or from storage issue as well.
Grade: There are four basic grades in Caviar: Beluga, Osetra, Sevruga, and Pressed and the grade will ultimately determine how the eggs are rated.
Maturity: Similar to fine wine or cheese, a caviar’s taste considerably improves when the eggs are processed at a certain time in the fish’s life. For example, the best tasting (quality) Beluga caviars are those that come from roe when the fish are 20-years of age.
Resiliency: There is a fine line when measuring resiliency. For example the egg must be strong enough to withstand the harshness of the caviar-making process, and still be soft enough to melt on the palate upon eating.
Separation: The separation on the eggs from the ovaries is a careful process. The initial sieving/filtration process needs to be delicate as it removes the attaching membranes that join the eggs together. The difficulty or easiness of separation during this stage governs how resilient the eggs are, and eggs that do not make it through this early stage, will certainly not be able to endure further processing.
Size: The size of eggs are determinate based on the type of fish from which the eggs were extracted. For example, Beluga caviar (the largest eggs 4-5mm) are the size of an average pea. In this case, only eggs that are 4-5mm (as determined by the accepted size range for that particular fish) from the Beluga Sturgeon will be deemed mature enough for harvesting to make caviar.