Enjoying Oysters in Months Without 'R'.

Printer-friendly version

As Summer Begins, Enjoy Oysters in Months Without 'R'.


At Hog Island we are frequently asked about the old adage, “only eat oysters in the months with a letter ‘R’.” Is it a fact or is it a myth, and is it safe to enjoy oysters during the summer months?

Exactly when and where the ‘R’ rule first appeared (c. 1700’s) is a bit of a debate; but historically, for health and conservation practices, it was best to refrain from eating oysters during warm water months. 

During the warmer months, as ocean temperatures rise, oysters naturally tend to spawn or reproduce.  For conservation practices, wild oysters were not harvested during the spawning seasons.  In this same era (c. 1700-1800's, pre-refrigeration) it was dangerous to ship and, ultimately consume, oysters that sat out in the heat.

Now, because of sustainable farming practices, strict water quality monitoring and advanced wet storage techniques it is healthy, and safe, to consume farmed oysters and mollusks all year long. Yet oysters remain a sensitive species whose quality and nature fluctuate with the seasons.

Terry Sawyer (TS), marine biologist and co-founder of Hog Island Oyster Co., answers some frequently asked questions about the seasonality of oysters.


Terry Sawyer, co-founder and Cheif of Operations, Hog Island Oyster Co.


Q. Is there any time of year when it is not healthy to eat oysters?

TS. Today, farmed oysters account for 95 percent of the world’s total oyster consumption. Farmed oysters are healthy and safe to eat all year long. Most oyster farming operations are well managed, well regulated and produce a highly sustainable product (Monterey Bay Aquarium Seafood Watch).

Proper handling of live shellfish becomes even more important during the warm summer months. At Hog Island, we take an extra step: putting all of our shellfish in a chilled, filtered seawater system for a minimum of 24 hours before sales.

Q. Do oysters have a season?

TS. Yes. Farmed oysters are similar to organically farmed produce. Oyster farmers don’t use fertilizers or food to boost oyster production; oysters receive all their food and nutrients from nature. Because of this, oyster conditions will vary as the natural food supply and bay temperature change across seasons. And different oyster species respond differently to climate, temperature, and growing location.

Q. What are oyster species? And what’s in an oyster name?

TS. MFK Fisher has inspired oyster lovers world wide with her famous quote, “American oysters differ as much as American people”. While there are literally hundreds (maybe thousands) of oysters with individual names and flavors, they all stem from just a handful of oyster species.

There are five edible oyster species: Eastern Oyster (Crassostrea virginica), European Flat Oyster (Ostrea edulis), Kumamoto Oyster (Crassostrea sikamea), Pacific Oyster (Crassostrea gigas) and the Olympia Oyster (Ostrea conchaphila).

Each oyster variety is unique in flavor and texture as well as well as having unique responses to seasonal water temperatures and growing locations. And, like grape wines, all oysters take on the flavor and essence of the region in which they grow; we call this merroir (we borrowed this term from wine producers' concept of terroir).

Because of their merroir, oyster farmers label oysters by name and growing locale as a way to distinguish the individual flavor experience. 

Q. What oyster varieties does Hog Island Grow?

TS. Hog Island raises Pacific (aka Hog Island Sweetwaters), Kumamoto, Atlantic and Olympia oysters as well as Manila clams and mussels.

Q. What are Hog Island’s best ‘Summer Season’ oysters?

TS. During summer time we recommend our Hog Island Sweetwaters (Pacific oyster) -- smalls or mediums for grilling. Some Pacifics will spawn during the warmer water months (June-Aug). When they spawn their meat tends to get creamy, which is less appealing for a raw bar but phenomenally sweet and delicious for cooking.

To counter-act this we farm in three distinct areas within Tomales Bay, so we also can always find some Sweetwaters that are right for eating raw in the summer – it just takes a little more work.

We also are just beginning to harvest our Kumamoto and Atlantic varieties, which we grow specifically because they are great raw the half shell all summer long. 

And, we have a beautiful and bountiful crop of Hog Island Manila clams this season. These are a delicious, tender and sweet little clam that cook up in mere minutes -- my personal favorite for an easy Summer feast!

Q. What would you like people to know about oyster farming and eating oysters?

TS. Though the summer season can be a challenge for all oyster growers, we work hard to produce great oysters year round. Oysters are a seasonal product, have fun and enjoy the different varieties as the seasons change. And, remember to always keep your oysters iced, or properly chilled up to the moment you’ll be eating them. 

Q. Do you have a favorite grilled oyster recipe for the summer?

TS. I really enjoy the fresh, simple flavors of Hog Island Oysters grilled 'Farm Style' (from the Hog Island Oyster Lover's cookbook).