By JANET FLETCHER

IF YOU'RE IN THE BUSINESS OF SELLING CHEESE, YOU'RE IN THE BUSINESS OF EVALUATING IT FOR QUALITY AND VALUE. But to be the most discerning cheese critic, you may need help (or a refresher course) on refining your tasting skills or adapting your process. That's why we've asked two leading experts and cheese competition judges to share their methods for appraising the look, smell, feel and taste of cheese.

Sharing their wisdom is: Daphne Zepos, former judging chair for the American Cheese Society competition and owner of the Essex Street Cheese Company, a New York-based importer of Comté; and Bill Wendorff a professor of food science and a dairy manufacturing specialist with the University of Wisconsin.

Step 1: Create the Right Environment
Before you start, set aside some quiet time when you can focus solely on the task. Don't undertake this exercise when you are on the sales floor, juggling customers and the phone—there are too many distractions. "The first thing I do is really keep to a method," says Zepos. "I always do exactly the same things in the same order. It allows you to pigeonhole all the information that's coming to you, and to weigh it properly."

Step 2: Judge the Appearance
Begin by evaluating the rind, if the cheese has one. Is it in good condition, or starting to break down? Wendorff looks for signs of mite damage or for cracks that could allow for contaminants to enter. If the rind is excessively thick it can reduce the yield of the cheese, he says. Note the entire wheel. It should be evenly shaped, not lopsided. If it is a mold-ripened cheese, does the mold look healthy and even?

Then cut into the cheese and examine it again. In a blue-veined cheese, the veins should be evenly distributed. For most cheeses, the color of the paste should be uniform, perhaps darkening near the rind. Does the cheese have eyes or cracks when it shouldn't, a sign of undesirable gas formation? Professional judges look for color defects, such as uneven or mottled color, pinking or browning. Internal pinking can suggest the presence of hydrogen sulfide.

"I look at the heel of the cheese, where the sides meet," says Zepos. "That's the canary in the mine, where you find a lot of information that is qualitative." Along with the layer of cheese just below the rind, the heel can tell you a lot about how the cheese is developing. "That's where the cheese will first liquefy and mature and sometimes gallop ahead of itself before the whole thing has started maturing," she continues.

You should also correlate what's happening on the rind with what's happening inside to discern whether a cheese is maturing uniformly, or whether the rind might be aging faster than the center.

Step 3: Evaluate the Aroma
Take a few moments to smell the cheese in several places and try to articulate the scents you find. Be on the lookout for undesirable aromas, like sour milk or the so-called "baby burp," that may signal unhealthy fermentation. Cheeses that smell ammoniated, stale, rancid or overly goaty should obviously get the thumbs down, but other aromas are more controversial. Technical judges at the American Cheese Society competition may mark cheeses down for unpleasantly earthy notes, wet-wool or barnyard smells, while the aesthetic judges—whose job it is to note a cheese's good features, not its flaws—may find that earthy and barnyard aromas, in moderation, can be appealing.

Step 4: Assess the Texture
"The information that comes through the fingers is important," says Zepos, who pokes and probes rinds to determine how moist, tacky or powdery they are. Professional judges also evaluate the body of a firm cheese by squeezing a piece between thumb and forefinger and noting the resistance. A weak-bodied cheese will break down quickly, becoming mushy with one or two squeezes. To practiced eyes like Wendorff's and Zepos', this breakdown indicates poor cheesemaking practices. With experience, you can also come to know what a cheese should feel like during the texture test.

"How much butterfat remains on your fingers?" asks Zepos. "Does it become crumbly or pasty? If I squeeze Comté between my fingers and it doesn't become a homogeneous paste, if it crumbles, I'm going to be very perplexed. If a Lancashire becomes a pile of gravely bits, I'll be concerned. If I squeeze a piece of Manchego and it doesn't leave enough fat on my fingers, I'm going to have a problem with that. But if Cheddar leaves me with oily fingers, I'm like—whoa, what's this?"

Step 5: Appraise the Flavor
To a purist, there are only five flavors: sweet, sour, salty, bitter and umami (the savory taste). All of those flavors are, or can be, present in cheese, and you should keep them in mind as you taste. Are they in balance? Although aged cheeses contain no sugar, they can have a caramel-like sweetness. All cheeses have acidity and would taste bland without it, but do you taste too much acidity? Salt, too, is essential but should not be the first thing you taste. A technical judge like Wendorff will probably always deduct points for bitterness, while an aesthetic judge—such as a merchant—may enjoy the faint bitterness of a Serpa or Torta del Casar, Iberian cheeses coagulated with an enzyme derived from a member of the artichoke family.

Taste slowly, letting the sample dissolve on your tongue and noting its texture. Is it sandy, crumbly, grainy, silky or creamy? And is the texture pleasing? While the cheese is on your palate, you will perceive more aromas, so take the time to articulate them. "Write down every word that comes to you," urges Zepos. "And then push yourself to go deeper."

Instead of noting simply that a cheese is nutty, ask yourself what do you smell? Roasted peanuts? Walnuts? Hazelnuts? Is it a buttery smell like the fragrance of freshly churned or melted butter? Prodding yourself to be more precise will help you build a better taste vocabulary. And remember that flavors often unfold slowly, so make note not only of what you perceive at first, but of how the cheese finishes.

As you take yourself through the various evaluation areas, record your notes in a format that makes sense to you. Develop your own point system that reflects the weight you give to appearance, aroma, texture and flavor. "In the end, what is important is to distill all this information into the one thing that made the cheese memorable," says Zepos. "It could be the texture. It could be the long aftertaste. What has caught your attention most?"

Janet Fletcher is a staff writer for the San Francisco Chronicle and author of The Cheese Course.