How to Tell if It's Oyster Season

Rules for Buying and Eating Oysters

Oysters on the halfshell
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You may have heard that good oysters are available during months that contain an "r" in its name. The rule dates back to the days before refrigeration when oysters could spoil quickly. These days, you can enjoy oysters throughout the year, but it is still important to know when and where you can get the tastiest oysters that won't leave you feeling ill.

Timing and Bacteria Matter When Eating Oysters

Perhaps the best reason to only buy oysters during the fall, winter, and spring -- the "r" months -- is due to the creature's reproductive cycle.

Oysters spawn in the warm summer months, usually May through August (although Gulf oysters spawn year-round due to the warm waters). Spawning causes them to become fatty, watery, soft and less flavorful. Shucked in the colder months, oysters instead have the more desirable lean, firm texture and bright briny flavor.

In recent years, bacteria such as Vibrio parahaemolyticus have caused illnesses in several harvesting areas of the eastern United States throughout the summer months. The bacteria are not unique to oysters; high levels can be found in tuna, mackerel and other seafood. Because oysters are consumed raw, there’s a particular focus on this infection. The presence of Vibrio nonetheless puts a tick in the column of enjoying oysters only in cooler temps.

Year-Round Oyster Enjoyment

Thanks to refrigeration, you can consume good oysters in spring and summer without incident. You can acquire them from cool waters or from farms, which gives them optimal flavor even in a month without an "r." In fact, a new genetic procedure being used by some commercial oyster farms renders farm-raised oysters sterile, so they don't spawn at all.

These prime oysters are available for year-round enjoyment.

When Is the Best Oyster Season?

Know your oyster. If you feel confident that you are getting a fresh oyster from a cool-water location, you should have a tasty oyster that will not make you sick. Likewise, if you are in a state along the Gulf of Mexico, have no fear.

If you are barbecuing or whipping up some oysters Rockefeller, warm-weather bivalves pose no threat. When dining on local catch, though, note the weather. In those cases, you may want to stick to the old "r" rule -- better safe than sorry, right?