Two hours into wandering the grocery store I finally realize I need a steak, bad. And once standing at the meat case--that trove of satiny, garnet jewel-like pieces of mammal cut into reassuring symmetries--I'm faced with that familiar dilemma: What to choose? At a supermarket, steak cuts can differ $10 or more per pound in price, with $5/lb. sirloin at one end versus $15/lb. tenderloin at the other. Prices at upscale markets can be much higher still. A 16 oz. strip steak at the Prime Rib costs $40.95, but a monstrous 40 oz. slab is less than $20 at Michael's Steak and Lobster House on Eastern Avenue. Why the disparity? The real question is what makes one steak sublime and another taste like ass--figuratively, since it very well may be?

Obtaining beef has been greatly streamlined thanks to the profound, albeit earth-killing conveniences afforded by industrialization. Centralized distribution has also made it nearly impossible to determine a steak's provenance when buying it from a supermarket, as most of us do. The upshot is lower cost and more uniformity. Breed, diet, and intramuscular fat, or marbling, are factors determined in the course of the animal's life. After slaughter, it's all about cut, aging, and cooking.

Modern cattle descend from a single ancestor, the aurochs, which evolved two million years ago. First domesticated around 6,000 b.c., over 250 modern breeds exist; of about 60 present in the U.S., a third are used for beef production. About 80 years ago, beef production transitioned from older working or dairy animals to those raised specifically for meat. Cattle were confined in lots to limit unnecessary exercise and fed mostly corn to fatten them quickly. In 1924, Congress authorized federal beef grading, and two years later USDA beef grades based on marbling and maturity were officially codified.

Prime, the highest grade, represents the top 2 percent of animals based on highest fat content and maturity. Calculating maturity involves fairly complex skeletal and muscular analysis, but boils down to younger being better. Most Prime beef goes to restaurants, and what's left for retail sale is hard to find and nearly double the price of Choice, which is the grade designating the top 50 percent of beef. Prime beef is available locally at most boutique markets.

Cows are ruminants, possessing specialized organs that allow digestion of high-cellulose plants like grass. Feeding primarily on corn causes numerous health problems, which then cascade into a myriad of human health and ecological concerns. A resurgence of grass-fed beef production has gathered momentum in response.

These cows are more expensive to raise since they take longer to grow, and tend to be leaner since they are less sedentary. Grass-fed beef can range from herbaceous and complex to gamey and slightly off, so producers often feed their animals grain just before slaughter to smooth out the flavor. Tenderness can also be an issue. Selecting breeds that are better grass converters, such as Wagyu (of Kobe beef fame) and Hereford, and post-slaughter dry-aging can greatly enhance flavor and tenderness; as such grass-fed beef is almost always dry-aged. (The dry-aging technique basically involves hanging a piece of beef in a climate-controlled environment for two weeks or more.) Whole Foods stocks a small selection of Argentine grass-fed beef, and Trader Joe's carries some from Australia and New Zealand. Graul's Market (7713 Bellona Ave., [410] 823-6077) in Ruxton and Victor's Meats (5113 Roland Ave., [410] 433-8855) in Roland Park stock and order (respectively) grass-fed beef that is also locally produced.

Though the Maryland Cattlemen's Association estimates that there are 4,500 beef cattle farms in Maryland, less than 1 percent produce beef exclusively, making locally raised beef frustratingly difficult to find. Butchers I contacted in five municipal markets--Lexington, Northwest, Hollins, Cross Street, and Broadway--and area supermarkets were generally not knowledgeable about locally sourced beef. In any case, tracing commercial beef to its geographic origin is nigh impossible, even at the wholesale level. Local slaughterhouse J.W. Treuth and Sons (retail store at 328 Oella Ave., [410] 465-4650) estimates just 20 percent of the animals it processes come from Maryland, and are not normally identified as such.

Some producers, such as Springfield Farms in Sparks and Hedgeapple Farm in Buckeystown, sell on site, but just two make it to retail in Baltimore. At the downtown farmers market, Bel Air's Hickory Chance Farm sells beef from cows fed grass or silage, finished on grain, and then dry-aged as whole carcasses which results in deep, earthy flavor. Harford County's Level Farm's beef is available through Broom's Bloom Dairy at the Waverly farmers market. I was told that Level Farm's cows have "pasture access," but I suspect they are fed mostly grain because Level Farm also grows corn; its beef is spectacularly tender.

Though Graul's stocks local beef and Victor's, sells it, less proximate butchers such as the excellent M&M Meats (3278 Main Street, Manchester, [410] 374-2884) do so as well. Notably, Victor's will special order for you from any of their myriad of suppliers, covering any conceivable permutation of cow attributes discussed so far. Also, they will dry-age any piece of beef for you, regardless of cut or weight, at no extra charge, which really sets them apart.

Still, options remain and we must hack away at the rock to reveal the masterpiece. What's the best cut? Ceriello Fine Food (529 E. Belvedere Ave., [410] 532-1840) in Belvedere Square boasts the best selection of Prime beef in town with no less than 11 different cuts from which to choose. And once secured, how best to cook a piece of meat in which you have invested the equivalent cost of 40 fast-food cheeseburgers? How you prepare your cut is just as important as the quality of beef you choose. Stay tuned.