I know that there is a specific ratio for salad dressing. I believe it is 3 parts oil to 1 part vinegar. That seems like a heavy dressing. I know I could just switch the ratio, but I was wondering, is there a reason why that is the typical ratio?
That ratio is often quoted, but really it should only be considered a starting point. There is no one “correct” ratio. That will depend on the vinegars and oils you use, the kinds of salad and salad dressing you’re making, and your personal taste.
The most basic salad dressing is vinaigrette, a simple mix of oil, vinegar, salt, and pepper. According to Madeleine Kamman in the revised edition of The Making of a Cook, the following proportions are those “generally accepted by the Old World and Latin American countries”:
For a very acid vinaigrette, use 50 percent each oil and vinegar
For a medium-acid vinaigrette, use 35 to 40 percent vinegar and 60 to 65 percent oil
For a mellow vinaigrette, use 25 percent vinegar and 75 percent oil
The Romans preferred mild dressings. This little saying sums it up in a memorable way, “It takes four persons to make a salad; a wise one to add the salt, a miser to add the vinegar, a spendthrift to add the oil, and a crazy one to toss the salad.” I think Americans tend to prefer mellower dressings, too (that partly explains why there’s sugar of some kind in almost all commercially available varieties. There are other reasons as well, but suffice it to say it’s there to benefit the manufacturer, not the consumer.) Hence the recommendation for the ratio you refer to.
What kind of salad oil is your go-to? If it’s a neutral one like vegetable oil (either one or a mix of soy, canola, or corn oils), you’ll need more of it to offset the acid of the vinegar. With a more flavorful oil like extra virgin olive or walnut oil, not as much will be required. The kind of vinegar matters, too, as they can vary in acidity from 4 % in rice vinegar up to 6.5 or 7 % in red wine vinegar. Red wine vinegar needs a lot of oil and a fair amount of salt to tame it for dressing a salad.
As in other areas of cooking, salt balances acid and vice versa. So if you find your dressing too acidic and don’t want to add more oil, try adding a bit more salt, tasting as you go. Other modifiers include egg or egg yolk, and heavy or sour cream. Vegetable juices or fruit purees add flavor and reduce the need for oil. If you’re concerned about calories, there are recipes which use chicken broth (homemade, please; commercial ones don’t have enough gelatin for body) as an extender. In a pinch, you can even add a little water; just don’t overdo it.