Oysters gone wild? Send ‘em back

Special to The Times

WHEN it’s a real scorcher outside, slurping icy-cold oysters and sipping a crisp Chablis sounds like the perfect refresher. But eating oysters in the summer isn’t always a winning proposition. At some restaurants, the oysters are always fantastic, so firm and briny you’re tempted to order more. But in other places they might seem unpleasantly flaccid and creamy, a result of warm-weather spawning. And unfortunately, at some spots, when you speak up about spawning oysters on your plate, you get little more than a blank stare from your server.

What gives? If the old adage advising us to avoid oysters in months without an R in their names (May to August) seems to still ring true sometimes, why is it passe elsewhere? And if oysters are on the menu, can you be sure they won’t be spawning?

The old saying was sage advice when oysters were harvested and consumed locally. As water temperatures rise in warmer months, oysters spawn, or release eggs and sperm into the water. It’s all about impulse, scientists say, so once one oyster begins the process, all those nearby get into the mood. Afterward, oysters are lean and languid. Spawning is hard work.


Eating a spawning oyster won’t make you sick, but it’s not a pleasant experience, either. When fertile, their texture is soft and creamy, and not in a good way like cheese or ice cream. Afterward, they’re thin and flabby, lacking in meaty substance.

Today, restaurants often ignore the old rule and serve oysters in the summer because they have consistent access to oysters from cooler climates. In the summer, oysters are harvested from the Pacific Northwest (Northern California to Washington to Canada), Northeast (Maryland to Maine), and below the equator (New Zealand). Ordering oysters from cooler waters is a good way to hedge your bets, but it’s not foolproof because spawning is about temperature, not season. “Warm” is relative to an oyster, depending on what temperature the little guys are accustomed to. Oysters from cooler climates spawn at lower temperatures than oysters from warmer waters. But even those imported from New Zealand, where it’s winter now, can still be spawning when harvested.

“It’s dependably unpredictable,” jokes Jon Rowley, director of marketing for Washington-based Taylor Shellfish Farms. “I had a couple at lunch the other day, and I could tell they were just starting to get the urge.”

Fortunately, you easily can tell an oyster is spawning.

“Spawning oysters look foamy and milky, even a little slimy,” says David Lentz, executive chef at the Hungry Cat in Hollywood.

In theory, a good restaurant should never serve a spawning oyster. Chefs train their line cooks to spot spawning oysters (or at least they should), even if they’re serving oysters from icy-cold waters. But detecting them isn’t always easy.

When oysters are just beginning to spawn, the reproductive sac is still quite small. “It looks like a thin, cream-colored line off to the side of the oyster. Most people wouldn’t even notice it,” says Blake Wheeler, buyer for American Fish and Seafood Co., a Los Angeles-based wholesale and retail seafood supplier.

Even trained chefs can miss signs of spawning. “Early on, the creaminess is hidden, more underneath or just inside the oyster, so it’s harder to see,” says Allyson Thurber, executive chef at the Lobster in Santa Monica.

Chefs depend on their suppliers to provide top-quality shellfish and reduce the likelihood of serving spawning oysters.

Providence executive chef Michael Cimarusti seeks out suppliers he can trust. “Better farms will limit production in warmer months, setting oysters in deeper, cooler waters,” he says. “But the key is to rely on really good purveyors who won’t sell you spawning oysters in the first place.”

At Water Grill downtown, executive chef David LeFevre orders oysters a few days before planning to serve them (oysters can live up to a week out of water). When they arrive, he shucks a couple from the bushel. “If those aren’t spawning, chances are they’ll all be good since it’s a group thing,” he says.

But even with the keenest trained eye, you still might end up with a few spawning oysters on your plate, especially if they’re just getting their groove.

In the early 1980s, a high-tech method was developed to curtail the spawning problem, but it proved to be less effective than hoped. Scientists used chemical or pressure shock to trick oysters into adding a third chromosome. These genetically modified oysters (known as triploids) were sexless, so they never spawned.

But the process isn’t foolproof. As many as 20% of treated oysters don’t convert, which means spawners are still a problem. And those that do become triploids are more susceptible to premature death than their diploid cousins.

But it’s the appearance of triploids that’s been the biggest hurdle to their widespread use in restaurants.

“They taste the same as diploids, but they’re almost gray in color, not as glistening or appetizing,” says Jeff Pearson of Taylor Shellfish. “When you open up a triploid, you see more of the shell because they’re not as muscular or meaty.”

Despite their shortcomings, some hatcheries plant triploids in the summer months because they permit a longer growing season in areas that used to be too hot for summer harvesting. And despite appearances, they taste exactly the same as their diploid cousins.

In the end, recognizing when an oyster is hot and bothered is a very useful skill.

Look for the telltale milky sac that indicates an oyster is spawning. If it’s just getting going, the sac is little more than a thin, cream-colored line less than half an inch long. If the oyster is in high gear, the sac will be large and cloudy, overtaking much of the oyster’s body mass. And if that’s what you see on your plate, you shouldn’t hesitate to send them back, either at a restaurant or to your retailer.

Says Thurber, “If we don’t catch it, tell us. A restaurant wants to know.”

To serve oysters at home, buy from a reputable seafood purveyor. And in the summer, choose varieties grown in cooler waters.

Luckily, you won’t have to worry about whether they’ll spawn on the car ride home, even if it’s a little toasty outside. “Clams can spawn right in the box,” says Rowley. “It’s a real mess. But I’ve never seen an oyster do it.”

Once you get home, shuck a few to make sure they’re not spawning (if they are, return them right away). Store them in the refrigerator for up to a week, bottom (flat shell) side up, and cover in moist paper towels (plastic bags will suffocate them).

When you’re ready to serve them, just look them over for any telltale milkiness as you pile them on ice. Then pop open that chilled Chablis and savor summer’s deliciously briny little pearls from the sea.