Classic Kasu -- It's Practically Mainstream In The Northwest

IT MAY FALL INTO the category of being trendy Pacific Rim cookery, but kasu is much more than that. It is, in fact, classic Japanese cuisine.

Kasu, for those who have not stumbled upon it on menus of some Seattle restaurants or in seafood markets, is actually the leftovers (often referred to as the "lees") of fermenting rice used to make sake. This fragrant, doughy substance is then used to marinate seafood such as salmon, black cod or halibut to produce a dish of subtle but exotic flavors.

Kasu probably got its start as a preserving or pickling agent and is still used in the preparation of pickled vegetables such as daikon radish or cucumber. Its adaptation to fish is likewise: It not only preserves the seafood after days of marinating but adds a distinctive flavor that the Japanese savor and the Northwest seems to have adopted in a big way.

Kasu is not new to Seattle. As a traditional, time-honored dish, it has been served in local Japanese restaurants for many years. That's where Tom Douglas, chef/owner of the Dahlia Lounge, first discovered it 12 years ago, at the Mikado.

"I fell in love with it and began serving it at Cafe Sport," he says. (He was the chef there at the time.) "There's something about the cod version that just melts in your mouth."

More recently, it has gone nearly mainstream and seems to have become the latest discovery within the seemingly endless array of classic Asian cooking. One can find already marinated kasu cod in such stores as Larry's Markets and Thriftway on Queen Anne, for example. Douglas highly recommends the prepared version and even uses it today at the Dahlia where he often puts it on the menu as an appetizer served with "ocean salad," a mixture of seaweed, kelp and other ocean-floor greens.

I first became aware of its growing popularity when a writer from California telephoned to say he was writing an article on kasu and could go no further until he spoke to some Seattle chefs. Did I know of any?

Then just recently an article appeared on the kasu trend in a national magazine, and the author (Doris Tobias, a noted food writer) relied almost entirely on the Seattle restaurant scene and in particular Wayne Ludvigsen, executive chef at Ray's Boathouse. Was Seattle once again at the focal point of a hot new wave of cuisine?

Any mysteries about kasu and how to use it were quickly cleared up by a visit to Uwajimaya, Seattle's Japanese "supermarket." For $1.67 I had a pound and a quarter of kasu, more than enough to make dinner for four. As a by-product of sake (it is labeled sake kasu, by the way), apparently there is a plentiful and cheap supply of the stuff. It looks rather like bread or pizza dough and emits a faintly sweet aroma of baking bread mixed with, well, sake.

At the seafood counter I threw myself on the mercy of the smiling man behind the display of fresh fish who was delighted to help. First, he pointed out the tray of already prepared cod, a regular item there. He also reminded me that there was a recipe printed right on the kasu package if you were making your own. But it definitely needed some interpretation.

"First, you must soak the fish in brine," he said. "That opens up the pores so it will absorb the kasu." (That explained the five teaspoons of salt in the recipe.)

The next instructions were to mix the kasu with a small amount of miso, a spicy paste used in many Japanese dishes including the classic soup, along with some mirin or rice wine. This produces a more workable solution, somewhat the consistency of porridge. The main decision to be made, other than which fish to use, is how long to marinate. Two days is common for full flavors of the kasu, one day works for a more subtle approach and may be the best choice for those unsure.

As it turns out most kasu recipes are very similar. Slight variations substitute water for the liquid instead of rice wine and sometimes sugar is added to enhance the sweetness. The Japanese often pan fry or broil the fish, but American chefs lean toward grilling over a mesquite or even on a gas grill. It is important, all agree, to use a strongly flavored fish such as black cod (also known as sablefish) or salmon. The kasu would overpower a more delicate fish.

Here is a basic recipe for preparing your own kasu from scratch, followed by Douglas' version using marinated cod.

---------------------------------------- UWAJIMAYA'S KASU SALMON ---------------------------------------- 4 servings 4 fillets of fresh salmon (about 5 ounces each) 5 teaspoons salt 1 quart water (or to cover) 1 pound kasu 2 tablespoons miso 1/4 cup mirin or rice wine 1. Soak the salmon fillets in a salt-water solution for about 30 minutes. Remove and pat dry. 2. Blend together the kasu, miso and mirin until it becomes a soft paste. Place the fillets in a glass bowl and evenly spread the kasu mixture over the fish. Cover and place in the refrigerator for two days (one day if you want a more subtle flavor). 3. Before grilling, scrape off the kasu mixture, leaving just a slight film on the fillets. Broil or pan fry (12 to 15 minutes per inch of thickness).

----------------------------------------------- DAHLIA LOUNGE KASU COD APPETIZER ----------------------------------------------- 4 servings 1/2 pound kasu marinated black cod 1/4 pound ocean salad (found frozen or fresh in seafood stores) 1. Sear the cod, flesh side down, in a hot pan on top of stove. Then place the cod skin side down in an ovenproof dish or pan and bake in a 350-degree oven until done. Total cooking time should be 12 minutes per inch of thickness. 2. Serve the cod topped with a garnish of ocean salad.

Tom Stockley is a freelance writer and Seattle Times wine columnist. Benjamin Benschneider is a Seattle Times photographer.