What’s the best oil for everyday frying? I’d long figured that the choice is a matter of taste and price. I usually use canola oil because it’s neutral in flavor, a good source of omega-3s and inexpensive. It costs about a dime a tablespoon, whereas extra-virgin olive oils can cost more than a dollar.

Partisans of the olive maintain that a high-quality extravirgin oil brings its special flavor and health benefits. More recipes now suggest it for frying and other high-heat techniques, not just for drizzling. But does it make enough difference that it’s worth a tenfold premium in price?

I investigated the flavor question by heating 15 oils ? 4 olive and 11 seed oils - so I could taste what heat alone does to them. And I served some of them to trained oil judges.

We were surprised at how thoroughly heat obliterated the flavors in cooking oil . Even prize-winning, and costly, extra-virgin olive oils lost much of what makes them special, though they retain their apparently healthful pungency. It seems more economical and effective to fry with an inexpensive refined oil and drizzle on a little fresh olive oil after cooking.

Many oils have little or no flavor to begin with, as they’ve been refined to remove almost everything except the oil molecules. This is true of most oils extracted from seeds, including canola and soy. The nine refined seed oils I tested were almost odorless. Some seed oils, including peanut and sesame, are also sold in unrefined or partly refined form. They’re more sensitive to heat and start breaking down, developing unpleasant flavors . When heated to a moderate frying temperature , only the unrefined sesame oil had a distinctive flavor. The other 10 seed oils tasted slightly nutty and fried.

Olive oils are pressed from fresh fruits, so their flavors can vary tremendously. Of the four tested, one was an inexpensive “light” olive oil, made primarily of neutral refined oil, with very little aroma. The other three were labeled “extra virgin,” a standard that in theory signifies an unrefined oil of good quality but in practice doesn’t signify much at all. The first two were a fruity Spanish oil and a spicy, pungent one from California. Both were international medal winners . The third was a suspiciously inexpensive bottle from an upscale supermarket, a blend from Mediterranean countries. After I’d heated them, none of the olive oils had much olive flavor left.

I took the olive oils to a meeting of the University of California’s olive oil research group which evaluates oils from all over the world to provide guidance to California’s young oliveoil industry.

In a blind tasting of the four unheated olive oils, the six tasters easily distinguished the medal winners from the cheaper oils and found many interesting aroma notes in them, from tea and mint to green banana, stone fruit and cinnamon.

For the second tasting, I heated each oil to 177 degrees Celsius for five minutes. The panel ranked the heated light oil higher than the heated pricey California extra-virgin oil, whose pungency had become overbearing.

So the choice of everyday frying oil should indeed be a matter of taste. Choose as cheap or expensive oil as you like. But learn to taste the difference between good fresh oils and stale or funky ones.


HAROLD MCGEE
ESSAY