David McCoy, better known as The Scotch Doc, is one of world's foremost experts on single-malt scotch whiskey. He spoke with us to help answer a reader’s question in the October issue about judging scotch. Here are more of his thoughts:

On the growth of scotch: “A dozen years ago you only saw Glenlivit and Glenfiddich at bars and liquor stores but now there are many more brands. There are currently about 80 distilleries in operation." (McCoy's personal collection includes 900 different single malts from 127 distilleries.)

On defining “taste”: “You often see a scotch or wine taster proclaim that he senses a given aromatic in the beverage and half the people in the room look at each other, puzzled. Whenever anyone describes what he tastes in a single malt, it simply reflects his palate and olfactory condition and bias at that moment. Never allow someone make you feel deficient or inferior if you aren't tasting the same thing.”

On tasting scotch: “The first bit that goes into your mouth is usually a total waste due to what I call ‘alcoholic shock.’ To avoid this detraction, subtly stick the tip of tongue into the scotch in the form of a sip, quickly pull it back into the mouth and move it around in your mouth for about 10 seconds. The natural saliva dilution will get you past the shock and you can better analyze the remaining sips.

“Next, take a small sip, maybe half a teaspoon, and move it around your mouth. Swallow it, then breath slowly in through your mouth to pull the gasses off your tongue, teeth and remaining mouth cavity and up into your sinuses to the olfactory. Finally, slowly exhale through your nose with your mouth closed.

“After you've swallowed each sip, close your mouth and breath slowly. The first 10 seconds can be quite profound and then it’s going to reach its peak in intensity and level off. A really good scotch will flatten out and hold its peak for five or 10 seconds and more. The total olfactory experience, as measured by a Bell curve, can last a minute or more."

On the glass to use: "The experienced imbiber will order scotch in a 12-ounce brandy snifter, with a glass of room temperature water and teaspoon on the side. But there aren't glasses made specifically to capture the nuances of single malts, so I designed my own." (McCoy sells the glasses for $25 each at his site.)

"Here’s a tasting trick used by distillery officials around the world: Put about a fourth or an eighth of a teaspoon of your favorite single malt on the palm of your clean, dry palm. Put your other hand on top and rub it together. Bring your hands up and cup them over nose and breath in slowly. Repeat the procedure several times. You'll see what the warmth and moisture of your hands does to the flavor of the whiskey. That's also what your mouth does. When I visit a distillery in Scotland, I will put a few drops in my palm and make note of the most appealing ones for me then later return to those to have an ounce or two.”

On single malts versus blends: “A single malt is defined as a scotch that comes from a single distillery, distilled in a copper pot still, made exclusively with barley and aged in Scotland for a minimum of three years in wood casks. A blended scotch is made by starting out with about 85 percent neutral grain spirits and adding a selection of up to 34 scotch single malts until they get the flavor blend they want. My favorite blended scotch is Famous Grouse, which uses a higher proportion of single malts."

On stocking your home bar: "Start with Glenkinchie, which is a Lowland scotch. Do that neat, put one drop of water instead of a half teaspoon. Next try Dalwhinnie, which is a typical Highland single malt. Glenmorangie is a Highlands scotch that is aged using bourbon casks exclusively. Another Highland, Macallen, is the scotch I would take to a desert island. Get the 12-year-old. Unless you are really into scotch single malt, the 18-year-old is too expensive. The Macallen is aged exclusively in Olorosa sherry casks. Finally, try the Laphroaig or Lagavulin, both from the island of Isla whosescotch single malts have a lot of smoke and peat."