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Penn Cove Select
Gorgeous, ruffled shells holding consistently plump, white oysters with black mantles. Penn Coves are multiyear winners of the West Coast’s Most Beautiful Oyster contest. They are a prime example of the “clean finish” style of Pacific oyster—light, salty, fresh, like a cucumber sandwich rolled in parsley.
Samish Bay and Whidbey Island, Washington
Famous as a Chesapeake oyster river for centuries. Of the twelve oysters on this list, Rapps are the quietest. Extremely mild oysters, exhibiting a simple sweet-butter flavor, they are easily overshadowed by saltier or fruitier oysters, so they don’t fare well in mixed tastings. But on their own, with the most evanescent of wines, they can be delicacy itself—a lesson in the pleasure of minimalism.
If Penn Coves exemplify the “light and lettucey” side of Pacific oysters, Skookums show Pacifics at the other extreme. These rich and musky oysters grow fat on the “algae farms”—mudflats—at the head of tiny Little Skookum Inlet, one of Washington’s oldest oyster sites. The brown and green algae that thrive on the mudflats, different from deep-water algae species, give Skookums an aroma of trillium and river moss, more earth than sea.
Little Skookum Inlet, Washington
The oyster that begs the question: Nature or nurture? By nature, it’s a virginica, the East Coast oyster, celebrated for its superior texture. But it’s nurtured in the gentle algae baths of Totten Inlet, famous for producing full-flavored Pacific and Olympia oysters. The result is an unlikely yet dazzling mutt—fat and round on the tongue, but cleaner and more mineral than a Pacific. If you prefer the Totten Virginica to Pacific oysters raised in Totten Inlet, then chalk one up for the Eastern oyster. If you prefer Totten Virginicas to East Coast virginicas, that confirms Totten Inlet’s revered status.
Totten Inlet, Washington
Print Our Oyster Poster Artwork for CHOW by Bryan Christie Design
Ask an oyster farmer what makes his oysters sweet and he will say glycogen—the starch that oysters store as an energy supply. Ask any food scientist, and she will tell you that glycogen is tasteless. It might add body to an oyster’s taste, but not sweetness. How to explain this disconnect? Well, starches are long chains of sugar molecules. Glycogen is made from glucose—the same kind of sugar we use in our muscles for energy. So while glycogen itself is tasteless, it can be broken down so that its glucose molecules fit snugly onto our taste buds that detect sugar. Voilà, sweetness! Our saliva is filled with enzymes that break down food (that, in fact, is saliva’s job), and oysters themselves have enzymes that will start to break down their tissue once they are dead. The question is this: How much time does it take?
Most people don’t chew their oysters long enough to get more than a whisper of sweetness on the finish. If you have an oyster fat with glycogen, and you chew a lot, you can get some real sweetness. But chewing an oyster twenty or thirty times is kind of like brushing your teeth for five minutes—it may sound like a good idea, but few of us are willing to do it.
A second source of sweetness in oysters may be glycine, the substance that gives shrimp and crab its sweetness. Glycine isn’t a sugar, but it’s one of several amino acids (protein building blocks) that taste lightly sweet to us. We may even have separate taste receptors for it.
An oyster stores food in two ways. In the fall, as the water cools, it eats as much food as it can, transforming that food into the glycogen that will keep it fueled through the dormant winter months when it doesn’t feed. An oyster in December will be at its fattest, and then will slowly thin through the winter as it lives off its reserves. By April, it is pretty thin. But then the water warms up and swollen rivers pour nutrients into the estuaries, fueling the spring algae blooms. The oyster feeds again, but this time, instead of storing its food as glycogen, it stores much of it as lipids—fat—which is necessary for producing sperm or eggs. It will taste buttery and rich for a brief time, until those lipids get converted to sperm or eggs, at which point it develops more of an “organ meat” flavor. (Some people like the taste of a spawny Eastern oyster. Nobody can stomach a spawny Pacific.) Depending on the warmth of the water and the type of oyster, spawning can take place anywhere from May to August. In the Gulf of Mexico and other points south, where cold water is not an issue, and where there is plenty of plankton year-round, oysters never go dormant. They will often spawn in sporadic trickles over months, rather than in a single spurt. They also don’t need to store much glycogen, so they never get as firm and fat as a cold-water oyster in the fall.
When an oyster is full of glycogen and lipids, it looks plump and creamy white or ivory. That’s what you want to see. It will taste firm, springy, and delicious. Transparency is a sign of a lack of glycogen—either it recently spawned or it just survived a long winter. At that time, it will taste like little more than a bag of saltwater. If it looks veiny, with bluish or whitish channels through the flesh, that’s a sign that it’s getting ready to spawn and is filled with gamete, not glycogen. Prick a spawny oyster and its liquid will look milky. Eat a spawny oyster and it will burst in your mouth like a greasy raw egg yolk.
On rare occasions, the water an oyster feeds on is so dense with a particular algae that it turns the oyster liquor blue, green, red, even gold. American restaurants don’t bother trying to serve these, especially the reds, which make it look as though the shucker has cut himself. The enlightened ostreaphile, however, knows that the famous Marenne oysters of France are finished in shallow saltwater basins dense with a blue navicule algae that turns their liquor and their mantles green and gives them a singularly rich flavor. No doubt exotic flavors lurk in the blue, red, and gold oysters, too, but don’t expect a wave of interest in the States. If you are French and you get a green or gold oyster, you squeeze yourself for joy, thank the gastronomic gods for delivering such a prize, and dig in. If you are American, you call the HazMat squad.
Not everyone prefers the algae-plumped oysters of spring and fall. A cadre of contrarians favor thin ones. Judy Rodgers, for example, of San Francisco’s Zuni Café, says, “I know I like ‘leaner’ oysters—literally, not full of food, stored as creamy glycogen, which is chemically equivalent to cornstarch. Leaner oysters have clearer, smaller meat and bright flavor notes, and they don’t coat your mouth.”
What Rodgers may be responding to in leaner oysters is umami—a fifth category of taste, separate from the familiar quartet of sweet, salty, sour, and bitter. Umami is perhaps best described as savory. It’s what makes chicken broth, soy sauce, and anchovies taste delicious. As with the other four tastes, we have taste buds specifically tuned to umami. If you love tea and tomatoes, you love umami.
The term umami comes from the Japanese word meaning “the essence of deliciousness.” Most eaters would have no quibble with that claim. Free amino acids, especially glutamate, are responsible for umami. Since amino acids are the building blocks of protein, umami tends to be found in abundance in meat and fish products that are cured, aged, dried, or otherwise abused so that their protein breaks down into its constituent amino acids. Parmesan cheese, Prosciutto ham, and smoked salmon are umami powerhouses. So are oysters. When an Olympia or European Flat is compared to caviar or anchovies, that’s the umami talking. When a Moonstone oyster is called brothy, that’s umami. A thin oyster may not have much sweet, starchy glycogen, but it can still have plenty of umami.
We don’t yet know what factors influence umami content in oysters. One may be minerals and metals. Ions of certain metals are known to break apart molecules in food. The most famous example of this is the copper kettles used to make Comte, Gruyère, and other cheeses, because the copper breaks the milk fat into delicious flavor compounds. Similarly, cast-iron pans and clay pots have long been known to impart good flavors to certain foods. Oysters are high in copper, iron, and other metals, and extraordinarily high in zinc (by far the highest of any food), so perhaps something similar happens in them.
One surefire way to increase umami in oysters is to let them sit in the fridge for a while. At 40 degrees Fahrenheit, they are dormant, but metabolizing ever so slowly, digesting their fats and glycogen in the effort to stay alive. As they metabolize without oxygen, they develop more propionic acid (found in milk and charcoal) and more amino acids—more umami. So an oyster that’s been out of the water for a week will be more savory, and have different flavors, than one that was pulled out that day.
For most people, that isn’t enough of a reason to let oysters sit. Virtually everyone agrees that an oyster pulled straight out of the sea tastes better. Freshness, in fact, is the single most important factor. To get that fresh sea taste we all covet, the oyster’s liquor must still be seawater, still alive and vibrating with microscopic life. After a couple of weeks, that liquor has been through the oyster a few times. It ain’t bad, but it ain’t seawater.