Every collection of eggs from an individual fish is unique. The value and quality of the harvested eggs are scored during production by a caviar expert, who judges the product according to grading guidelines for the average roe from that species. These guidelines rate caviar on a set of factors of which the scorer uses to decide the grade.
What factors change the caviar's grade?
Egg size: how do the grains of caviar compare to the typical egg size?
Egg color: does the product have the usual color, a color that is off, or a certain color that signifies rarer and more mature caviar?
Egg lucidity: do the eggs have the shiny coating that indicates freshness and proper storage.
Egg uniformity: is the general appearance of the caviar appropriate? Are all the grains uniform with each other in terms of size, color, lucidity and firmness?
Egg separation: Are the eggs clearly individual grains or are they soft, wet and seemingly melted together?
Egg fragrance: Does the product smell okay or does it have any off-putting and unnatural characteristics to its scent?
Egg firmness: are the grains sturdy or soft, and do they have the appropriate texture? Is the roe skin or shell too fragile?
Egg taste: Does the caviar have all the usual flavors of that species? Does it taste metallic, sour, bitter, and too salty or have any other flavors that negatively affect the quality?
Egg maturity: do the eggs not only look like but taste like they were harvested from a full grown fish?
After all these factors are considered, the caviar is usually grouped into one of two grades: Grade 1 caviar and Grade 2 caviar.
Grade 1, also referred to as #1 or A-Grade, is reserved for caviar that not only satisfies the norm for the species but ideally combines all the factors stated above. In order to be Grade 1, the eggs must have consistently firm yet delicate texture with large grains that are intact and unbroken, with fine color, smell and taste. Some producers will further rate the caviar as Grade 1+ for rarer quality product, or Grade 1A or 1B for caviar that lacks in one of the areas stated above yet still higher quality than Grade 2.
Grade 2, also known as #2 or B-Grade, is usually given to caviar that below average. This product can have normal grain size with good color and taste but might not be as pleasing to the eye or palate as a Grade 1 product. Grade 2 caviar might score poorly in more than one of the grading areas above, but is still good enough quality to pass as a malossol caviar delicacy.
Damaged product or product that would be considered below Grade 2 is not given a rating and usually thrown away. However, some below grade product can be used as a base to make pressed or semi-preserved caviar.