One of the most common questions I am asked is “what kind of olive oil should I use?” There are so many olive oils available and the labeling is very confusing. Yesterday, Kitchen Conservatory had a class on olive oil, which included a tasting of several oils. My first recommendation is, taste the oil and use the oil whose taste you like. The fat that you choose to cook with — whether it is butter or lard or other meat fats or vegetables oils — will carry the flavor of the food. It is very important to cook with a fat that tastes delicious.

Most liquid fats are used because they have no flavor. The oils have been deodorized and neutralized so that the fat adds no additional flavor. What’s the point of cooking with fat that has no flavor! Fat is such a critical element of cuisine that we always want to use a fat that has lots of flavor, particularly a flavor that tastes delicious to us. The vast majority of the olive oils available have been deodorized to remove any connection to an olive. And then the “olive oil” has a green coloring added just to confuse the customer! Any oil labeled as “light” or “virgin” or “pomace” or “refined” or “pure” has been purposely stripped of all flavor. So you might as well cook with less expensive corn or soybean oil.

A delicious olive oil has three characteristics: fruit, pepper, and bitter. Olive oil has a maximum shelf-life of two years and age is not a benefit. The fresher the oil, the better the taste. Old oil tastes musty. Ideally, all olive oil bottles would include a “born on” date. Bitter may not sound like a flavor that we want in food, but the purpose of oil is to blend with food. A good olive oil should catch in the back of your throat.

I have not mentioned “extra-virgin,” because, unfortunately, many oils that are labeled as “extra-virgin” have been faked. Don’t automatically trust an “extra-virgin” label, but trust your own tastebuds.

Superior olive oils should not be heated to more that 350 degrees, because the flavor of the oil will change.

Our class on olive oil featured two recipes that were very popular: tuna slow-poached in olive oil and a cake made with olive oil instead of butter. For the tuna, I used Colavita extra-virgin olive oil with a strong pepper taste. I had previously made this tuna recipe with a plain, tasteless olive oil and the difference in taste when using the better oil was extraordinary.

Generally, the olive oil from northern Italy is more fruity and the olive oil from southern Italy is more pungent. So I used a very fruity olive oil in the cake and everyone pronounced that olive oil cake as the best ever. Try it and use your favorite cake recipe and substitute a good olive oil for the butter in the recipe!

Oil-Poached Tuna

2 cups extra-virgin olive oil

2 garlic cloves, smashed

1 sprig of thyme or other herb of choice (ginger, lemongrass, tarragon, rosemary, parsley, etc)

1 bay leaf

Zest of one lemon or lime or orange

1 tablespoon salt

1 teaspoon peppercorns

1 pound fish or shellfish

Use a pan that is about the same diameter as the tuna. Warm the oil to 150 degrees (use a candy thermometer) with the garlic, herbs, bay, lemon, salt, and peppercorns. Let the flavors steep for 10-20 minutes. Do not let the oil get hotter than 180 degrees. Add the fish and gently cook until the tuna has an internal temperature of 120 degrees, about 20 minutes, depending on the thickness of the fish. Drain. Serve warm or chilled.