Dress up summer salads with a homemade vinaigrette

When it's too hot to cook, salads are best when dressed as lightly as the person assembling them.

Heavy, mayonnaise-based dressings are about as suffocating as a winter coat on a hot day, but vinaigrettes add flavor without overpowering the crisp, cool lettuce and raw ingredients that can fill up your belly without heating up the house.

Like most processed foods, many commercially made vinaigrettes and salad dressings rely heavily on salt and sugar, often in the form of corn syrup, for flavoring. But with just a few ingredients, you can make better tasting and cheaper vinaigrettes at home.

The traditional vinaigrette ratio is 3 parts oil to 1 part vinegar, but how much oil and vinegar to use depends entirely on your own taste buds and on what kind of vinegar you're using, says Jeff Conarko, co-owner of Con' Olio Oils & Vinegars at the Arboretum.

Three-to-1 works for cutting down tart, non-aged vinegars that are twice as acidic as the more expensive aged vinegars, such as traditional balsamic and sherry, Conarko says. When making vinaigrettes at home, he prefers to use one part olive oil with one part thick, slightly sweet balsamic vinegar that has been aged at least 12 years.

You can add all the herbs, garlic and lemon juice you want, but if you're using rancid oil or cheap vinegar, your salad will suffer.

Unlike balsamic vinegar, freshness is the key to good olive oil, Conarko says, but because of the Food and Drug Administration's labeling rules, it's hard to know how old even a brand new bottle of olive oil is. "We don't get the good stuff," Conarko says. "In other countries, after a year, they throw in out or sell it to America." (Expiration dates and the words "first press," "cold press," "virgin" and "extra virgin" are also unregulated, although the agency is currently considering enforcing stricter rules.)

When olive oil is fresh, the smoke point is higher (400 degrees compared with 360) and the good-for-you oleic acid and antioxidants are high.

Balsamic vinegar labels can be just as confusing as those on olive oils. Unless the label says "traditional" or "tradizionale," it's likely a knock-off, usually called something along the lines of "balsamic vinegar di modena," which is made with red or white wine vinegar and caramel coloring. (The mid-grade balsamic that isn't as high quality as the traditional but isn't swill will be labeled "condimento" or "condiment.")

There's geographical logic behind the classic combination of balsamic vinegar and olive oil. "Anywhere you can grow grapes, you can grow olives," says Conarko, so it's natural that the two pair well together in a dressing.

If you're using red, white, rice or nonaged sherry vinegar, add a hint of sugar, jam or honey to offset the acid. You also can use juice from lemons, limes or oranges in place of or in addition to vinegar. (Traditional balsamic vinegar is naturally sweet without any added sugar and a glycemic index of zero, which is a welcome change for diabetics who are monitoring their sugar intake.)

You can substitute other oils, including the catch-all "salad oil," which can be any number of nearly tasteless vegetable oils. Specialty oils such as those made from sesame seeds, pumpkin seeds, avocados, grape seeds and walnuts can impart a unique flavor on your vinaigrette, but they have an even shorter shelf life than olive oil, so buy in small quantities.

No matter what kind of oil and vinegar you're using, the best way to emulsify the two is with a whisk or in a blender. You can shake the mixture in a jar in a pinch, but the dressing won't be as well mixed. In addition to adding flavor, mustard (any kind but the bright yellow mustard meant for hot dogs) or honey can help keep the vinegar and oil emulsified.

Don't skip the freshly ground pepper and salt, which brings down the acidity of the vinaigrette and enhances the flavor of the oil. Fresh herbs such as basil, tarragon, oregano, marjoram or thyme always impart more flavor than their dried counterparts, and the finer they are chopped, the better distributed the flavor and less intrusive they are on each bite.