Each Tuesday the Register reviews an area restaurant, with an emphasis on establishments where a couple can dine for $30 or less. Reader suggestions are welcomed.

Occupying one of the best-looking brick buildings in Calistoga, the Hydro Bar and Grill could be expected to be an expensive, fancy place.

Not so. Hydro has an extensive menus of bar plates as well as regular fare that's both tasty and moderately priced.

Hydro is located on Lincoln Avenue in the heart of Calistoga's downtown. With its big windows, exposed brick walls and high ceiling, Hydro is a relaxing refuge that's open breakfast through dinner. We dropped in for lunch on a chilly winter weekday.

Among the dozen luncheon entrees were quiche, the pasta special of the day, lasagna and macaroni and cheese, burgers, chicken, B.L.T. and Reuben sandwiches and a grilled "bistro style steak."

The steak, at $16.95, was the most expensive item on the menu. The majority of items were under $10 and included fries or a green salad.

A big part of Hydro's business apparently occurs at the bar which has live music on weekends. A sign touts "hydrotherapy," including 20 tequilas, 20 bourbons, 20 micro drafts and 50 premium wines.

This helps explain Hydro's extensive bar menu, including fried calamari with spicy chipotle aioli, steamed mussels in a yellow curry-coconut broth, tacos, green rice and black beans with creme fraiche and a medley of nuts roasted in olive oil and thyme. Most bar plates are $6 to $10 range.

We were taken by the day's list of specials, including a $6.95 cheese fondue. Not able to recall the last time we'd seen fondue on a menu, we made this cheesy dish our appetizer.

For our main dish, I picked the "Tuscan-style" sausages with crispy polenta, while my companion chose the Vietnamese-style salad with shrimp. Both items were $9.95.

We were in no hurry. From our corner booth, we could see people coming and going at the busiest intersection in town. Towering over us was a large art nouveau French poster. Along the long interior wall, mirrors. In back, a large horseshoe bar in aquatic green.

Business on a weekday in January was light. Our server checked in throughout to make sure things were going well.

It didn't take long before a bowl of bubbling cheese surrounded by cubes of sourdough bread arrived. This fiery cauldron reminded me of one of those hot springs for which Calistoga is famous.

The menu said the fondue was a blend of white cheddar, creamy jack and Jarlsberg cheeses with a dose of kirsch and pale ale. Whatever the ingredients, the result was a wonderfully gooey pot of intense flavor. My companion described the dish as "fun food."

We immediately asked for more bread. This fondue dish was good enough not to waste a stringy morsel.

We were only half-way through the fondue when our main plates arrived. This was bad timing.

Momentarily diverted, when we returned to the fondue we found that it had begun to harden into a plastic mass that was no longer dipable. Had the fondue been served over a flame, it would have held up longer.

With the thrill of the fondue gone, we moved on.

My sausage and polenta was superb. The cube of polenta, as advertised, was crispy on the outside, which made it a far more interesting dish. It came with a fresh marinara sauce with parmesan and parsley.

The two links of Caggiano's sausage were perfectly grilled and tangy. I've had many a sausage and polenta combo that was not nearly as satisfying.

My companion's Vietnamese-style salad featured a blend of red and green Nappa cabbage, spinach and lettuce, with sprouts and a topping of crisp, crumbled peanuts.

The dressing, made of soy, lime and rice wine, had a snappy cilantro highlight.

As for the shrimp, there were five plump ones. More would have been better, but the salad was a success anyway. Not a lettuce leaf or peanut was left behind.

Clearly, Hydro knows what it's doing in the kitchen. Based on our experience, this is a place that takes traditional dishes and adds its own deft touch.

Hydro is serious about wine. The back side of the menu was loaded with choices.

Hydro is located at 1403 Lincoln. Open seven days, breakfast starts at 9, dinners run until 10.

Readers with tips about interesting places to eat should e-mail diningout@napanews.com.