While there are many subcategories and fine distinctions in the area of canned crabmeat, there are just a few main categories. Knowing these will help you save money when deciding what type of crabmeat to purchase for the meal you're planning.
(NOTE: These grades refer to pasteurized refrigerated canned crab, not the small shelf-stable cans that are found in the canned fish aisle.)
The Lump crabmeat grades are the most expensive, followed in order by Backfin, Special, and Claw
Colossal lump (also known as Mega Jumbo or Super Jumbo) are the large chunks of meat that connect to the swimmer fins. There are only two of these muscles per crab, which is why it's so expensive (often $40-50 or more per pound.)
Jumbo Lump crabmeat chunks are the same two muscles, just from smaller crabs. Both are excellent for those times when you want great whacking hunks of crab to lift with your fingers and dip in butter or your sauce of choice.
Colossal and Jumbo have a fine texture and sweet taste that should be fully and consciously savored -- which is why they're not a great choice for crab cakes: the seasonings might overwhelm the delicate flavor and mixing the ingredients would break up the tender chunks. In other words, it would be a poor and pricey use of such a delicacy.
Lump grade crab consists of broken Jumbo lumps and large chunks of body meat. It's less expensive than the Colossal or Jumbo grades, but still has bright color and superb flavor. Lump crabmeat is best for fancy, impression-making dishes where appearance matters, like Butter-poached Crab or Crab Louis, where you want big, fork-friendly chunks. It's also the grade of choice for fine dining restaurant-quality crab cakes, as the chunks are large but will hold together with minimal binders.
Backfin grade is made up of smaller, broken chunks of Lump crabmeat mixed in with flakes of white body meat. It's less expensive than Lump crabmeat, but has good flavor and enough texture to look appealing in dishes where the crabmeat is somewhat visible, such as crab salads, pasta dishes, and conventional crab cakes.
Special grade consists of smallish flakes of white crabmeat taken from the body cavity. It's best for dishes where good color and delicate flavor are more important than visual impact. Excellent for dips, bisques, omlettes, mayo-based salads, etc.
The least expensive and most flavorful grade, claw meat is pinkish-brown rather than white and has a hearty crab flavor that doesn't get lost under seasonings. Great for soups (such as this Manhattan Style Crab Chowder), crabmeat stuffing, tacos, stir-frys, etc.