Just like wine, oysters carry the flavor of their environment — a concept known as merroir. The water they grow in, combined with genetics and farming methods, creates a unique experience for your palate. Whether you’re savoring a briny West Coast oyster or a petite East Coast variety, understanding what shapes these flavors can deepen your appreciation.
You can think of the variations in oysters, much like the variations in wine. Where it’s grown, and how it’s grown determines the final product for you to consume. That combination of factors is known as merroir (terroir for wines) when it refers to combined water conditions. Usually there are certain characteristics, or where you first experienced them, that form one’s preference. Folks that grew up on the East Coast mostly prefer East Coast oysters and so on.
A deeper look reveals, just like us, it is a combination of genetics, nature, and nurture. Are the primary forces. Oh, and the location where we grow up makes a difference too.
Location
Oysters are a natural product that vary from area to area, season by season. The mineral composition in the water of a given estuary is pretty constant. Just think of how a beach can be sand, shell, or rock in its nature. That becomes the “liquor” or water you find around an oyster.
The next variable is the tide in a given area. In some cases, oysters are fully exposed to the air at low tide. These oysters have to tighten up more to avoid being exposed to air. That means the abductor muscle grows a little firmer. This can lead to a more clam-like texture. If you imagine extraordinarily high air temperatures that coincide with a radical low tide, you understand why billions of oysters we killed in the PNW Heat Dome of 2022.
In all cases, they won’t sustain if high tide places them below 12ft depth on a regular basis. This is why our local coastal area is not viable for commercial oyster production. It is also the secret to seedless oysters (info for another day.
Rainfall is the most variable, compounding force of nature that impacts oysters. Generally, rainfall into the estuary lowers the brine, or saltiness, of the water. The liquor inside the oyster is the water from the estuary. (another debate here about keeping it or pouring it off your oyster). Less rain equals high brine. More rain equals lower brine and may be called a sweet water oyster. Oysters grown near the base of the Olympic Peninsula will be generally lower brine since that mountain range is officially a rain forest (+100 inches of rain per year). In this case, proximity to the coast and interaction of fresh water is positive. However, if the rain runs off from a farm or dairy it can cause closures near the coast. This is why a notable local area has closures after heavier rains.
This is another part of why location is so important. Since we grow primarily one type of oyster in the west, most become known by their location. Fanny Bay, Hama-Hama, Totten Inlet, Tomales Bay, and such are just locations. Each one has characteristics and variations form all the factors listed above. They will generally be consistent in that but again, it is a natural product with seasonal variation.
Genetics
There are generally three types of oysters commercially produced on the west coast. Listed based on volume of production (think 10s of millions every week).
+85% Miyagi oysters account for the vast majority of production here in the west. They originated in the miyagi prefecture (like the name of a state) in Japan and arrived in the 1940s.This deep-cupped (and you’ll se why that is important in a moment) grows quickly reaching market size in a mere 18 months.
10-15% Kumamoto (Kumis) are grown for seed that originated in that prefecture in Japan. This oyster is slow growing, taking 3 or 4 years to reach market size. Even so, they are very petite, presenting as little more than a US quarter in size. Packed with amazing flavor and mineral finish, they have been described as “having butter for the first time.” Serious umami. The primary, high-end, producer is Taylor Shellfish in Shelton Washington. They come to market an average of 3 or 4 times the cost of other oysters. Luckily, the second largest producing region is Humboldt Bay (Bill’s origin story location). The hard part is getting supply on this side of the redwood curtain.
<5% The Olympia is a native oyster here. It was virtually wiped out at the end of the 19th century by detritus from gold mining inland. It is a flat oyster (similar to the Belon in France) and lacks the ability to expel heavy metals. While nearly extinct, one major farm has joined with the state of Washington in beginning to bring them back. It takes about 4 years to reach harvest size which is slightly larger than a dime. Amazing wild flavor in a very small package.
East Coast oysters are more of a specialty here. Generally, they are all the same native variety (gigas virginicus) grown all along the eastern seaboard. I have developed strong ties with two farms back there. Look for Summer Love or Beau Soleil long about the middle of summer.