If the Bay Area food scene were a cotillion, grass-fed beef would be its newest debutante.

Although Northern California's history with cows fattened on nothing but local pastures goes back more than a century, it was only this spring that a serious retail alternative to classic American grain-fed beef hit town.

So far, suppliers of the new beef can barely keep up with demand. That's because chefs like Laurence Jossel of Chow and Park Chow find the taste as well as the politics of grass-fed beef appealing -- so much so that he decided to use only grass-fed beef in the approximately 100 hamburgers he sells every day at his two restaurants.

"For me, it's about the product. The flavor is cleaner," he says. "And after reading a bunch of stuff and understanding what goes into growing grain- fed, I think it is definitely the right thing in a lot of ways."

The boom started early this spring, when an alliance of Northern California ranchers began selling steaks from grass-fed cows to some high-profile restaurants, among them the new Acme Chophouse in Pacific Bell Park. Alice Waters, who has taken an interest in the politics of how beef is raised, tasted it and liked it. Shortly thereafter, the beef showed up in Berkeley Bowl and other high-end meat counters.

The product took off. When the sales force at San Francisco wholesaler GreenLeaf started distributing the beef in late March, they had two clients. Now, the list has shot up to more than 20 names.

That's because in the choosy Bay Area market, the idea of beef grown by local ranchers, without antibiotics or hormones and without any connection to sprawling, industrial Midwest feedlots, has both political and culinary appeal -- even though grass-fed beef is twice the price of conventional beef sold at most supermarkets.

Ever since the grass-fed product was introduced, there has been a strong debate running through the culinary community that goes beyond any environmental and social impact. It's about taste. Some people find that the delicate, lighter texture and more complex flavor of grass-fed beef has an edge over grain-finished beef, even the beef that comes from producers like Bay Area favorite Niman Ranch. A pioneer in the natural beef movement, Niman Ranch's cattle feed on pasture longer than most conventionally raised animals, and are fed grain only in the last part of their lives to achieve that beefy, well-marbled, corn-fed taste and texture.

Is grass-fed beef a better choice in the kitchen? To find out, The Chronicle's Food staff compared the handling and taste of grass-fed hamburger and tenderloin head-to-head with meat from Niman Ranch as well as "supermarket beef" -- meat raised almost exclusively on grain and grown in feedlots with hormones and antibiotics. We also spent time working with grass-fed sirloin and hamburger, grilling it, roasting it and turning it into meatloaf.

In the end, it became clear that which type of beef you choose is a matter of price, politics and personal preference.

We found plenty of surprises, most remarkably that grass-fed beef is an entirely different sort of meat with a distinct taste and less saturated fat. Researchers have determined that the structure of the fat itself is different from beef fattened on grain, with more omega 3 fatty acids and conjugated linoleic acid, or CLA, both of which are thought to help fight cancer. There is also less omega 6, which is predominant in conventionally raised beef and is suspected of contributing to heart disease. Exactly how much is in the beef and whether it really makes a difference has yet to be proved.

The fat in grass-fed beef tastes lighter and doesn't coat one's mouth like corn-fed beef. You can eat a rib-eye at lunch and won't feel as bogged down in the afternoon as you might after eating a conventional steak. One way to think of it, if you're a sushi lover, is to compare grass-fed beef to leaner maguro tuna and conventional beef to the richer toro tuna.

Raw grass-fed beef feels and handles more like veal than the muscular, beefy slabs of supermarket beef or Niman beef. The flesh is slightly slick and paler than the bright red supermarket meat with its waxy white fat. Niman, by comparison, had a brick-red hue and more subtle, creamier colored-fat.
Grass-fed beef cooks much faster, which is the most significant difference in the kitchen. Chefs who work with it regularly say they found it takes a quarter to a third less time. If you like medium or even well-done meat, you might not be happy with a grass-fed steak cooked to that temperature because it will be much tougher than conventional meat.

"It'll get away from you faster than you think. Once it gets past medium rare it's on its way," warns executive chef Thom Fox of Acme Chophouse, the first restaurant in the city to highlight grass-fed beef on the menu.

Grass-fed has a couple of other unusual properties. For our test of hamburgers, we used beef with about 20 percent fat and pan-fried each burger to medium-rare, which we tested by peering inside the burgers and by using a thermometer.

We cooked the grass-fed burger to an internal temperature of 140 degrees (considered medium-rare), but the meat looked rarer than that and yet tasted like it had been cooked longer, all the way to the medium stage. We also found that the longer the meat sat at room temperature, the redder it got. (We chose 140 degrees to assure we didn't overcook the delicate grass-fed beef, even though the Department of Agriculture recommends ground beef be cooked to an internal temperature of 160 degrees, or medium.)

The Safeway brand beef lost the most fat and moisture -- a 5-ounce patty became a 3.8-ounce patty after cooking. The grass-fed patty lost the least amount of fat and moisture, dropping from 5 ounces to 4.4 ounces. The Safeway burger developed the best crust and, surprisingly, was the clear favorite in flavor -- Food staffers said it tasted like a home-style burger and evoked memories of childhood cookouts. Niman beef had less appealing flavor, and many deemed it bland.

A few tasters liked the grass-fed flavor, saying it reminded them of pasture. But others thought it had a "hoofy" or "barnyard-y" taste. The texture was softer and even spongier than the Safeway brand.
"If I fed this to my kids, they would not eat them -- they would think it was weird," said one staffer. However, few could taste any difference in a meatloaf, made with 28 percent grass-fed beef.

Which brings up an important point about grass-fed meat: Because it is considered more of a handcrafted, seasonal product (most animals are killed in the late spring or early summer in California), the quality can vary from farm to farm and even from animal to animal. Feedlot cattle eat the same mash of corn, antibiotics and roughage to make sure the beef will taste similar, whether you buy it in Manhattan or Walnut Creek.

Evening out the taste is key to Niman Ranch's operation as well. Animals from its network of ranches are finished in the same feedlot with a mix of corn, wheat and barley to assure a consistent uniform taste. The Western Grasslands Beef alliance, which supplies the Bay Area restaurant market, aims to do the same thing by finishing off its cattle in one pasture and on hay.

What the animal eats certainly affects flavor and marbling, but it is just a small part of what makes a steak tender. As important is the breed, how and at what age the animal is slaughtered, and how the meat is hung and aged.

Animals that were stressed at slaughter are called "dark cutters." Their meat is unpleasantly dark and tastes of acid and iron because of a surplus of adrenaline and lactic acid at the time of the kill. About 2 percent of the cattle slaughtered for beef are dark cutters, and aren't sold for human food.

Grass-fed ranchers and Bill Niman make a point of keeping the animals calm before slaughter, of killing them as close to the feedlot or pasture as possible and doing it as humanely as they can.

The difference really showed in our second test, which used three whole tenderloins from Safeway, Niman Ranch and Western Grasslands Beef. We first tasted each raw, sliced thinly as for carpaccio. The grass-fed beef was delicate, with a distinct, pleasing mineral taste that was superior to the supermarket brand, which had virtually no flavor. Niman had its share of fans, who said it tasted richer and had a beefier flavor profile and had a springier texture.

In the pan, seared to an internal temperature of 125 degrees and left to rest for 10 minutes, the differences remained apparent, and personal preference came into play. There were some tasters who recognized the all- American flavor of the supermarket beef and thought it might take well to grilling. But no one preferred it. Rather, people leaned toward grass-fed or Niman. The texture of the Niman tenderloin was mushier than the grass-fed beef, which was surprisingly tender. But the grain-fed flavor of Niman was unmistakably appealing.

That's because most tasters were raised on the distinct flavor of corn-fed, well-marbled beef, and the flavor evokes memories of what a good steak should be. Still, there is no denying that the grass-fed tenderloin appeals to people for its cleaner mouthfeel, its more complex flavor and the generally lighter feeling tasters had after eating it.

And then there is what for many is the bottom line: cost. Both grass-fed and Niman Ranch were hugely more expensive -- more than double the price of supermarket beef. At Berkeley Bowl, Niman Ranch and grass-fed ground beef were $4.99 a pound. At Safeway, the hamburger was $2.79. Niman tenderloin and grass- fed -- which could only be obtained through a special order -- was a whopping $24.99 a pound. By contrast, the Safeway tenderloin was $12.99 a pound. A New York strip at Berkeley Bowl was $14.49 for either grass-fed or Niman. At Safeway, the cost was $7.99 a pound.