Getting oysters in shape

It’s all oysters, all the time, here at Starving. But don’t blame me. Blame Kate.

Kate, who writes about her own food procurement adventures at Living the Frugal Life, asked a very good question on the previous oyster post. To save you the trouble of looking for it, I print it here, almost in its entirety (I’m leaving out the part where she excuses me for my unjustifiable pride):

Just out of curiosity, what would make your oysters taste better than another? I get it that the waters would matter. But knowing little about oyster farming, I would assume that any oyster from the same waters yours are being raised in would taste much the same. Is there any way in which your practices affect flavor?

The short answer, alas, is no. The flavor of an oyster is determined by what it eats, and it eats whatever’s in the water. We have no control over what’s in the water. Ergo, we have no control over the flavor of our oysters.

We do, however, have some control over their shape. And shape is critical to the oyster experience. A round, full shell with a deep cup houses a meatier oyster than a thin, oblong shell. And the meatier oyster isn’t just bigger; it’s different. It feels fuller and denser when you eat it, and I strongly suspect it has a different body-to-muscle ratio.

An oyster has two adductor muscles, one attached to each shell. The rest of it is body. If you didn’t like oysters, you’d describe the body as slimy and flabby. It’s soft and slippery and your teeth go right through it. The muscles are firmer, and have a texture of what we think of as seafood. If you’ve ever eaten a scallop, you’ve eaten an adductor muscle, and the ones in the oyster are similar.

It may be that a larger oyster simply has larger adductor muscles, but it seems to me that it also has more muscle in proportion to the rest of its body. Whether that’s true or it isn’t, and I plan to someday do the research, a deep-cupped, large-bodied oyster gives the impression of being more substantial and having a larger, more assertive sweet spot.

Which compounds are responsible for which flavors in oysters is a question that hasn’t been conclusively settled. Some people say the sweetness comes from glycogen, which the oysters store for energy, but glycogen is tasteless until enzymes in our saliva break it down to sugars we perceive as sweet. Few of us chew oysters long enough for the to happen, and other people speculate that the sweetness comes from glycine, an amino acid that’s a component of seafood protein. (Then there’s umami, which a fall oyster, full of energy stores, is likely to have, but that’s a discussion for another day.)

A deep-cupped oyster, even though it ate from the same water that the thin-bodied oyster next door did, does taste different. It tastes richer and fuller and sweeter, although some of that difference is undoubtedly simply the difference in size. It may be a difference in the experience, and not the flavor per se, but that doesn’t change the fact that the deep-cupped oyster is better.

As a hard-assed empiricist, this namby-pamby, fact-free explanation bugs the hell out of me. As I learn more about oysters, and taste them, blind, side by side, I hope to be able to do better next time.

I can do a little better, although not much, in explaining how oysters grow up to be either deep-cupped and broad or shallow-cupped and narrow. Some of it is genetic, but the rest is growing conditions.

There are two ways (that I know of) to encourage your oysters to grow round and deep. The first is to give them plenty of space; if they’re overcrowded, they tend to grow into big bananas, with a long, thin lip on their outer edge. The second is to periodically break off the fragile edge of the shell that is the new growth; if they can’t grow long, they grow deep.

Our oysters had a lot of space until very recently, when our trays started to get overcrowded as the oysters got big. And I think we broke edges off fairly often, although we didn’t set out to do it as a growing technique. We shook the grow-out bags regularly to keep the oysters from cementing to each other or the bag, and we noticed that it slowed growth and tended to make for a good, deep cup. (Some growers tumble oysters to break off new growth.)

And we’re back to where we started – the degree of control that we have over the flavor of our oysters.

Kate, I hope that answers your question.

5 people are having a conversation about “Getting oysters in shape

  1. Congrats! I happy for you and Kevin. Its a lot of work to get oysters from spat to a harvestable product and you folks have done it well. Keep up the good work.

  2. sonja stewart says:

    Lots of interesting information! My parents used to make them in milk and butter. I have hated them ever since. The thing I remember most is that greenish grainy stuff in them. What is that???

  3. Why, yes! It does answer my question. I’m so honored it garnered an entire post in response. Thank you for the explanation; it was most interesting. Sorry it took me this long to get to your post. Things are a bit crazy at the moment – my husband fractured his thumb, which means I get to play nursemaid AND chauffeur (chauffeuse?) to all the doctor’s appointments.

    By the way, and apropos of nothing, your oyster pictures bring back strong but decidedly non-culinary memories. The only paid job I’ve ever had that my degree in archaeology prepared me for technically if not actually was sorting mussel and oyster fragments from a Native American midden. The trash heaps of California’s coastal dwellers, basically. It came down to counting the teeny-tiny tips of the shells of each species and getting rid of all the other fragments. Because the tips could be counted as actual half shells, while the fragments meant nothing definite. The fragments were so small I had to push them around paper plates with eraser tips. Fortunately I only kept that job long enough to earn an international round trip airline ticket. But if it ever comes down to distinguishing a mussel from an oyster based on the merest bit of ancient shell, I’m your woman.

  4. I’m glad to know at least a couple of you find this interesting.

    Sonja — the grainy stuff is the stomach contents. If you find this icky, I recommend that you don’t think about it too much. Just eat and enjoy.

    Kate — It’s good to know I have someone to call if I ever need shell fragment identification! Sorry about your husband’s thumb. I suppose we don’t really appreciate the miracle of opposable thumbs until we break one. I wish him a speedy and complete recovery.

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