The oyster must be pure.

This is what we're told, anyway—especially on the West Coast, where we are spoiled with bivalves that grow meaty and complex and sweeter than the Gulf Coast brine. They're served pristine on the half-shell, pure of liquor, the ultimate expression of terroir. In certain quarters, you get dirty looks for using lemon, let alone trying a mignonette.

So when Olympia Oyster Bar chefs Melissa Mayer and Maylin Chavez come along with promises to change Portland's oyster game, I'm eager to see how it turns out.

The spartan, white-walled and blond-wood eatery—with long communal tables and a little elbow of an oyster bar—opened on North Mississippi Avenue in mid-December. Mayer and Chavez had been honing their bivalved vision in booze-fueled pop-up dinners "where oyster is king" since August 2014, with slow-rolling buzz building like the tide.

But it turns out reinventing oysters ain't easy.

First, let's say that without exception, every oyster among the many varietals at Olympia Oyster Bar has been a beauty, as sumptuous and obscene as any nude painted by a master. They're served three ways—raw, naked and dressed, three words that also serve as the place's tag line.

photo by Rachael Renee Levasseur
photo by Rachael Renee Levasseur

Raw oysters ($15 for six, or chef's choice at market rates) are delivered daily direct from the oyster farm, and garnished with pickled serrano, Tapatio sauce and Key lime wedge. They're served French-style, with the lower foot still attached to the shell to keep freshness. One could order all day and never go wrong—especially between 4 and 6 pm, when the price drops to $12 for a half-dozen.

But Olympia's A-game is staked on naked and dressed. And that's where it runs into trouble.

The "naked" oysters (four for $12), removed from their shells, are whimsical, chef-happy constructions, whether a mini-tostada or, as in the Kataifi dish, wrapped in a bird's nest of toasted phyllo that looks a bit like shredded wheat. The oyster is then spiced and fattened with a smoked avocado puree, pickled serrano jam and a pepper-sesame-sea salt dust designed by Iron Chef Morimoto. It's a balanced food composition—crunchy, spicy, sweet—in which the subtle, soft oyster is unfortunately less naked than invisible. The king, though naked, is wearing far too many clothes.

photo by Rachael Renee Levasseur
photo by Rachael Renee Levasseur

The "dressed" oysters (also four for $12), served in-shell, have similar issues. A pomegranate seed-and-serrano number, clothed in a dusting of toasted quinoa and a cut of micro basil, leaves the oyster oddly to the side: Pomegranate seeds demand attention, both from teeth and tongue, and even a basil leaf is chewier than an oyster, which slides past them and leaves you a lovely salad that neither required the oyster nor included it. A brightly tart, halved kumquat in another shell was even more troubling in this regard.

photo by Rachael Renee Levasseur
photo by Rachael Renee Levasseur

But a shoyu-ponzu oyster was revelatory. The fat of the oyster enriches a soy-citrus broth thickened by sesame, while the salt and umami in the sauce brings out the oyster's flavors. It's like fresh oyster sauce happening on the fly.

But the broader issue is that it's unclear how Olympia is meant to be used. The well-lighted, bright-walled space doesn't read as a bar, where you'd hang out before or after dinner. And though Olympia promised a world of whimsical Champagne or absinthe concoctions from Oven and Shaker bartender Ryan Magarian, the cocktail list currently offers a scattering of classics like a sweetly lime-ginger-whiskey Presbyterian ($10) with a strong ginger bite. The beer and wine menus fare better, with $5 local saisons and a farmhouse cider, and glasses of wine priced from $6 to $11.

But Olympia is also hard to use as a restaurant unless you dig deep.

Oysters rarely make for a meal. And twice upon ordering one of the few substantive-looking dishes—a bowl of mussels ($17), and a ponzu steelhead plate ($15)—Olympia had run out of the dish, an issue with sourcing that Mayer says they've resolved. A Hama Hama clam bowl ($15) was an excellent French-style wine cook-down loaded with fennel and leek.

After one $40 meal—lovely Matiz sardines served in their tin with chili and oil ($8), oysters and an extremely acidic shrimp ceviche ($10) with little crisped shrimp feet charmingly on top—I went home and made myself a sandwich.

It seems that Olympia has not yet really transitioned from pop-up—where well-heeled diners drop $100 apiece on a long parade of tiny bites built to impress—to a restaurant meant to serve the needs of the many. The chefs' talents are obvious, and the oysters are beautiful. But a month and a half in, Olympia feels less like a reinvention than a test lab.

EAT: Olympia Oyster Bar, 4214 N Mississippi Ave., olympiaoysterbar.com. 4-10 pm Tuesday-Friday, 11:30 am-10 pm Saturday (includes brunch).