A Basic Recipe

• A basic olive oil vinaigrette combines olive oil and balsamic vinegar -- or another kind of vinegar -- at a ratio of 3-parts oil to 1-part vinegar. Add a pinch of salt and pepper and perhaps some brown sugar and you've got a delicious salad dressing. Because this dressing contains no perishable ingredients, you can store it at room temperature for two to three weeks.

Spice It Up

• Transform an ordinary vinaigrette into something special with the addition of fresh herbs and seasonings. Add minced garlic or shallots, lemon or orange zest, rosemary, basil or dill. Whisk in a bit of Dijon mustard, which not only adds flavor but acts as an emulsifier -- preventing the dressing from separating. Once you add perishable ingredients, keep the dressing in the refrigerator at 40 degrees Fahrenheit or cooler and use it within one week. The olive oil may harden in the refrigerator. Place the dressing on the countertop 30 minutes before dinner so the oil can soften. Shake the dressing to combine the ingredients.

Make Ahead

• Homemade olive oil dressings have a relatively short shelf-life, depending on the added ingredients, but you should definitely make these dressings a few hours ahead of serving them so the flavors can meld. Whisk the vinegar and seasonings together in a bowl. Slowly add the oil in a thin stream and whisk continuously to make a thick dressing. Refrigerate dressings with perishable ingredients.

Safety's Sake

• Although olive oil and vinegar aren't hospitable to bacterial growth, any moisture in fresh ingredients can harbor bacteria, including the bacteria that causes botulism -- a serious and sometimes fatal food-borne illness. Always dry fresh herbs thoroughly before adding them to a salad dressing with an olive oil base. Keep the dressing refrigerated and store it for no more than one week. Discard any dressing that has an odd odor, flavor or color. Better safe than sorry.