Among the changes made as the DoubleTree became the Riverside Hotel over the spring was the introduction of a new restaurant along the south side of the Boise River. Open since June, the Sandbar Patio Bar & Grill is casual, with servers in shorts and T-shirts, eco-plastic cups and bamboo flatware. Almost all of its dining is outdoors, shaded by white umbrellas and the blades of stretched red sails. The open-air emphasis struck me as an especially obvious, smart idea: In summer, we all want to be outside anyway, so why not forgo the dining room altogether and just open for the season?

This might not work everywhere, but the atmosphere — located just yards down the path from the well-discovered patio at Joe’s Crab Shack, cool air coming in off the water — is as gorgeous as you are likely to find in Boise on a late summer evening. There is live music every day, and on a few recent visits, the patio was spirited with an appreciative, mostly older crowd.

In the current vogue, the Sandbar espouses an ideology of local, sustainable, and generally responsible choices (although one could argue that disposable anything, even recycled, is harder to justify than just putting in a dishwasher). The flipside of the menu lists a very respectable slate of Idaho vendors whose products are featured. This is not an obligatory gesture — the Sandbar goes further, making as much as possible from scratch, even baking its own dog treats.

Buns for burgers and sandwiches are delicious, house-baked Idaho potato rolls, which elevate every item they surround. A veggie “burger” ($5.99) with a grilled portobella mushroom and peppers on a slice of sweet, panko-breaded roasted eggplant was well-executed, and my wife and I both liked the Girly-Girl Chicky-Chicken Salad “Sammich” ($5.99). It’s good chicken salad, with apples and pecans, though a little loose and mayonnaisey, and the few grapes on the side would have made more headway if they’d found their way into the sandwich itself. Another recommendation didn’t hit the mark, though: The chicken in the Tuscan sandwich ($6.99) was left a little overlong on the grill, and carried no specific Italian accent we could taste.

Truly outstanding, though, was the brisket sandwich ($7.49), served au jus with thick slices of Snake River Farms Kobe beef stacked like Lincoln Logs on that wonderful potato bun, chipotle-horseradish sauce, and just-melted provolone. The brisket was perfect, not completely fall-apart, but buttery, like a tremendous pot roast from childhood memory. On its own, this dish makes me hopeful for the future of the Sandbar.

Be aware, however, that the above items are listed with a la carte prices — sides of house-made potato chips or fries are $2.99, a side of fruit is $5.99. The chips come with your choice of seasoned salt and are quite good. The fries, twice-cooked as the French do, are some of the best I’ve had in Boise. This said, the “side” portion is huge, more than enough for two people to share. My wife and I felt baffled by our packed-full table, the massive piles of fried potatoes and lonely sandwiches in their paper-lined baskets. Sandwiches should come with a side of something, anything, even if that means re-pricing the menu.

One signature idea with huge potential is the homemade ice cream sandwiches ($3.99 for a large, $1.99 for half), ice cream inside layers of cake with a shell of dark chocolate. The huckleberry and white cake version is delicious, the triple-chocolate version overwhelming in the best way. But each time we ordered one, we received wildly different cuts and sizes. Once, served in the same basket, one portion was literally half the size of the other.

Which leads to service, which was a bit rough. When we asked questions about the menu, one server simply answered, “I don’t know,” and walked away. We ultimately had to go find her on the far end of the patio to pay the bill. Another server was largely absent, forgot our drinks, and when we summoned her to order dessert, needed prompting on what kind of ice cream we wanted. When this server, too, disappeared, never to return, the astute bartender did come out to apologize, which was appreciated. But we felt overall, some core practices were lacking. I should mention, though, that the kitchen crew and management were especially helpful and open to all of my questions.

Weather permitting, the Sandbar will be open until Nov. 1, with a large Oktoberfest party planned for Oct. 5.

One luxury of an offseason is that it will give the management of the Sandbar a chance to refine its vision. The ingredients of something remarkable are already in place.

Email Alex Kiesig: scene@idahostatesman.com