Types of Oysters
There are over 150 varieties of oysters harvested and sold in North America, yet they comprise a total of only 5 species of oysters. And although each species does have its general characteristics in regards to flavor, their “finishing touches” can be attributed more to their merroir (local habitat) than to their species. In this sense, oysters are much like fine wine…each one is distinctly different from each other as they take on the flavors indigenous to the regions and conditions under which they were grown.
Pacific Oysters – Crassostrea gigas
Alternate Names: Japanese Oyster, Creuse (France), Miyagi
Examples: Penn Cove Select, Fanny Bay, Kusshi
Although it is the most commonly cultivated oyster on the US Pacific Coast, they are not native to the region. Pacific oysters were brought to the US from the Asian Pacific in the early 1900’s, and introduced in France in the 1970’s and are now the world’s most cultivated oyster. Pacific’s have shells with naturally ruffled edges (if they aren’t tumbled) and are distinctly more fluted (elongated) than other oysters. Shell colors range from gray/green to vivid multi-colors of royal purple, gold and jade green.
Although they have a wide spectrum of flavors, Pacific Oysters in general tend to have a sweeter, less briny taste than Atlantic Oysters. Common nuances of flavor include: varying degrees of brininess, creamy, herbaceous, melon (honeydew or watermelon rind), vegetal.
Pacific’s grow quickly and many reach market size in about 18 months.
Kumamoto Oysters – Crassostrea sikamea
Alternate Names: Kumi, Kumo
Kumamoto’s are another import from Asia, Japan specifically. In 1947 Kumamoto oysters were introduced to Washington State as a substitution for Pacific Oysters which had been ordered from Japan. They were never popular in Japan, but are one of the very most popular oysters in the US.
While Pacific and Atlantic oysters are widely cultivated in the US and are frequently named after the specific bay, river, or region they are cultivated in/near, Kumamoto oysters are so popular, so distinct, that they typically go simply by the name “Kumamoto Oyster”, although some establishments will include the area of harvest, such as “Kumamoto – Oakland Bay”. Primary cultivation areas include Baja California, Humboldt Bay, and Puget Sound. Not many farmers cultivate Kumamoto’s because they are a slow growing oyster and the seed is hard to come by. Because they spawn later, and in warmer waters, they are of good quality later into the summer than other oysters.
Kumo’s are a small oyster (only the Olympia oyster is smaller), having deep bowl-like cups with nicely sculpted and fluted shells. They have a creamy or buttery texture with a sweet, mild, almost nutty flavor and a melon-like finish. Because of their mild, unintimidating flavor and small size they are the perfect oyster for beginners, yet still enjoyed by connoisseurs as well.
Atlantic Oysters – Crassostrea virginica
Alternate Names: Eastern Oyster, Virginica
Examples: Blue Point, Malpeque, Wellfleet
Atlantic Oysters are the “great American oyster” and are naturally found along the North American Atlantic Coast from Canada southward to the Gulf of Mexico. Along with the Olympia Oyster, they are the only indigenous oyster found in North America.
Atlantic oysters are distinctly different than Pacific oysters in that they tend to be larger, have a tear drop or paisley shape, smooth shells and uniform colors of brown, cream and forest green. Virginica’s are also more affected by water temperature than Pacific’s are. In the relatively warm waters of Virginia a farmer can bring a Virginica to market size in about 18 months (just like a Pacific). But in the frigid Nova Scotia waters it can take up to 4 years for a Virginica to reach market size.
East Coast Oysters tend to be brinier than other oysters, with a crisp texture, clean flavor, a mineral accent and a savory finish. Northern Virginica’s tend to have a more intense brininess.
European Flat Oysters – Ostrea edulis
Alternate Names: Belon
Examples: Maine “Belon”
Although many European Flats are frequently called Belons, they technically can only be called Belons if they are from the Brittany region of France near the Belon River. Thus, while all Belons are European Flats, not all European Flats are Belons.
European Flats have smooth, round (saucer-like), flat shells with a shallow cup and seaweed-green color. You need to be a true oyster lover to enjoy them as they have the boldest of flavors in the oyster kingdom. They have a meaty, almost crunchy texture, with an intense mineral bite up front, a potent seaweed flavor, and a long-lasting gamey finish.
Due to the potency of flavor, and the amount of over-harvesting of this species, it can be rather difficult to find. There are not many farmers cultivating it.
Olympia Oysters – Ostrea lurida /Ostrea conchaphila
Alternate Names: Oly
Olympias are the only oyster indigenous to the US Pacific West Coast. They were so popular during the Gold Rush era that by the end of the 1800’s they were wiped out and for many years thought to be extinct. But some wild stock was eventually found in the Pacific Northwest and is now cultivated successfully by a few farmers.
Although they are from the same family (Ostrea) as their larger cousin the European Flat, Olympia oysters are the smallest of all the species with the average diameter being somewhere between the size of a nickel and a quarter. They are a finicky oyster, hard to cultivate, and can take up to 4 years to reach the grand size of a quarter.
Despite their diminutive size, Olympia oysters are potently flavorful, yet easier to approach than a European Flat. They have a creamy texture with strong flavors of sweet celery and bright copper with a long lasting metallic finish.