Cooking with Oils & Fats
The majority of cooking techniques we use depend on oil, either as a heat transfer medium, as a flavoring, or commonly both. Selection of an appropriate oil, the amount used and the temperature it is used at are all critical to success in cooking. There are also health and safety considerations to keep in mind.
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Select Suitable OilsEven the most casual cook needs at least two oils: a high temperature oil (400°F+) for deep frying, sauté and stir frying, and a flavorful oil like extra virgin olive oil for salads and low temperature cooking. If I wanted to minimize the number of oils I had on hand, I'd select Butter, Extra Virgin Oil, and Pure Olive Oil (and dark Sesame for Oriental stuff). In actuality, I usually have about a dozen oils. High heat destroys oils (polyunsaturates faster than others) and the byproducts of breakdown aren't good for you. You can use a high temperature oil at low temperatures (sacrificing flavor) but never use an oil higher than its rated range. With flavorful oils keep well away from the maximum or you will lose the flavor you paid extra for. Health factors are also a consideration, but intense controversy surrounds these (see our Oils, Fats and Health for details). The chart below serves the three leading theories including the "Anything in Moderation" theory which can select from either column.
Storing OilsMost oils are highly perishable because unsaturated fats are subject to oxidation and rancidity. All contain significant amounts of unsaturated fats (with the notable exception of coconut oil which is darned near eternal). Those high in polyunsaturates are most vulnerable and should be used within 6 months of opening while monounsaturates (Olive Oil) will last a year properly stored. Properly stored means in a tightly sealed glass jar or oil can in a cool
dark place. You can store oils very much longer if you refrigerate them, but
all (except Safflower Oil) will solidify to some extent, particularly Olive
Oil. This is not damaging and left at room temperature for a while
they'll re-liquify. I keep dark Sesame Oil in in the refrigerator, but the
rest I use up fast enough to store at room temperature.
Cooking MethodsSautéHere a small amount of oil is used at high temperature to quickly brown ingredients. Heat the pan moderately, add the oil and turn up the heat to bring the oil up to near its maximum temperature - but it should not smoke because that damages the oil. Then add the ingredients and leave to brown on one side. Make sure they have plenty of space and don't move them around. When done, turn over to brown the other side, again without moving (for vegetables you will have to move them around more). Sautéing is a favorite technique for restaurant chefs because it can be very quick and requires only modest attention once you're good at it. Clearly though, sautéing takes a bit more practice than most cooking methods since you have to get the heat and timing right by experience. The most commonly used oils are olive oil and butter (tasty, but needs more care with the temperature). Obviously other oils can be used as you desire or as called for by the ethnicity of the recipe. Meats must be tender cuts or they will just toughen, Depending on the recipe they may be floured or not. If not, they should be dry and brushed lightly with oil to prevent sticking. If floured, they should be dried before coating. Meat should be cut thin enough to cook through (for thicker cuts, after sautéing the sauté pan can be moved directly into a hot oven to finish cooking). Vegetables should be cut so they will all cook in the same time, hard vegetables small, soft vegetables larger (or you can cut them uniform and add in stages). In some cases more ingredients may be added at the end of sauté and the pan may be "deglazed" (by wine or flambé with brandy) to provide additional flavoring, or a sauce may be made.
Braising - Stovetop & OvenHere you start by frying the main ingredients in a small amount of oil, similar to sauté or stir fry. Ingredients may be added in the process, such as starting with onion, then adding meat, garlic and ginger while continuing to fry. Once you've reached the proper state of brownness, you add a small amount water (and probably a few more ingredients), cover tightly and either simmer on the stovetop, or in a preheated oven until the ingredients are tender. The recipe is finally finished up on the stovetop. The most common oils are Butter and Olive Oil but others can be used. The main ingredients may be cubed, or may be put in whole. For Stovetop Braising, after browning put in enough water to come up about 1/3 of the depth of the ingredients. Cover tightly and bring to a simmer. Check the liquid occasionally and turn the ingredients for even cooking. The pot must never run dry. Meat is done when it's fork tender. For Oven Braising, after the browning step, put in enough water to come up about 1/4 of the depth of the ingredients. Cover tightly and place it in an oven preheated to between 325°F/160°C and 350°F/175°C. Meat is done when it's fork tender. Whether braised on the stovetop or in the oven, many dishes end up back on the stovetop for finishing. The main ingredients are often removed and the remaining ingredients made into a sauce which then accompanies the main ingredients.
StewingStewing is pretty much the same as Braising except
you put in enough water or stock to cover the ingredients. Again, it starts
on the stovetop with browning, and generally ends on the stovetop with the
finish seasoning, reduction or thickening, but the middle portion can be
done either on the stovetop or in the oven.
Pan FryingPan Frying is similar to sauté except more oil is likely used and the ingredients are moved and turned more often. Generally the ingredients are removed entirely from the frying pan when sufficiently browned and the oil does not become part of a sauce, but may be used to fry additional items. Again, butter and olive oil are the most used oils but many others including lard, duck fat, goose fat (and even chicken fat if you're Jewish) are frequently used - unless you subscribe firmly to column 2 of the selection chart above.
Your beautiful and costly multiply stainless / aluminum / copper
frying / sauté pan will be often be useless because what you are
trying to fry sticks horribly, while that ugly old cast iron thing works
like a dream.
Stir FryStir frying refers to an Asian technique generally executed in a wok, a wide shallow pan of spherical shape. This technique uses a small amount of oil at high temperatures to cook ingredients very quickly preserving flavor and texture. The oil may become part of the recipe if a sauce is made. "Stir fry" is often used in the context of Western cooking simply because it's easier to say and write than "fry stirring". Oriental stir frying can be done in a sauté pan, but it will require more oil and it may be rather cramped for ingredients that wilt down during cooking - and you can't park ingredients up on the cooler sides as you can with a wok. A high temperature oil of neutral flavor should be used. Suitable examples are Grapeseed, Peanut and Olive Extra Light or Pomace, all of which have a smoke point well over 400°F/200°C. Start by heating the wok moderately, adding the oil and spreading it up the sides with a spatula to coat well before adding ingredients. The key to successful stir frying is cutting and organization. Cut ingredients to uniform size and thin enough to cook through very quickly. All preparation must be done in advance because the process is too fast and needs too much attention to allow distractions. If you're having rice it should be completely cooked before starting the stir fry. Heat the oil very hot for meat (but never smoking which damages the oil) and moderately hot if starting with garlic, ginger and the like. A good strategy is to cook any meat first at high temperature and set it aside. Fry other ingredients at a more moderate temperature, then add the meat back in when about done. Keep in mind the wok must never be overloaded. If chicken or meat is to be cut thin or shredded, it'll be easier if you sit it in the freezer for 20 minutes or so - enough to stiffen it up a bit but not freeze it. Start adding ingredients with aromatics (garlic, ginger, etc.) and then in order of cooking time. It takes a little practice to judge the timing. Ingredients should be kept in motion most of the time to assure even cooking. If some ingredients are done while others are not done yet, you can keep the done ones from getting overcooked by parking them up on the cooler sides of the wok. Many recipes call for a finish steaming or braising covered with a tight fitting wok lid and/or making of a sauce just as with sauté.
Cast iron woks are very rare, and a bit heavy to work with but do cook evenly. The best available choice is usually a heavy gauge bare carbon steel wok you season well with oil. The one I have was made by Atlas Metal Spinning in San Francisco and is of very fine quality and has a long wooden handle. Most woks have loop handles which must be handled with pot holders or oven mitts. Non-stick woks are made, but cannot handle the high temperatures and abrasion they are likely to encounter. Stainless woks distribute heat very poorly and don't take a good seasoning. Electric woks don't get hot enough and the heater element is well up from the center making a hot ring up where it should start getting cooler. If you're stuck cooking with electricity, you're better off using a regular burner on high with a ring stand just as with gas. Western stoves are not ideal for woks. They must be placed on a ring
stand and the hottest part will be around the center not the center
itself as it would be on the wok's native charcoal stoves. Keeping this
in mind, good results can still be achieved.
Deep FryingFor deep frying, heat your oil very hot (but never hotter than its rated for). Take care not to overload it with ingredients so the temperature stays very high. If it falls too low the items fried will become soggy with oil. Take particular care with meat that has been previously frozen because it exudes a lot of water. It should be thoroughly drained and firmly patted dry with paper towels, then fried in small batches. In general, 350°F/175°C is a good starting point for most ingredients, but if you're using a 350°F fat like lard, keep it a bit lower. You should be applying enough heat that the oil comes back to temperature by the time the current batch is fully done. For French fried potatoes, the experts recommend "blanching" by frying at 350°F/175°C until cooked through. When ready to serve do a final browning fry at 365°F/185°C. For donuts and similar fried bread items a fat solid at room temperature is highly preferred so they don't drip oil all over everything. Lard, tallow and hydrogenated vegetable shortenings are usable. People attempting to avoid saturated fats went to vegetable shortening but got an even worse trans fat problem. "Zero trans fats" vegetable shortenings are now available, but they are, of course, high in saturated fats.
For real production, the European deep fry pot and basket are best, but you're going to have a lot of oil splatter to clean-up, Do clean up right away because oil starts turning to varnish immediately and will be a lot harder to clean up in a day or two. Reusing Deep Fry Oil is permissible, within limits, if it hasn't been overheated or otherwise abused and has been filtered and stored carefully. Some oils are much more reusable than others. See the "Oxi" column in our Smoke Point & Composition chart. The lower the number the more durable the oil or fat. Note that common vegetable oils have very high numbers which means they aren't much good for deep frying. This is why fast food industry, hounded by "health advocates" to stop using beef tallow (very durable) use partially hydrogenated vegetable oils which are similarly durable (see canola vs. canola hydrogenated) - but these are trans fats now considered far more harmful than the saturated fats (beef tallow) they were hounded into giving up. When reusing oil, don't use oil fish was fried in to fry anything else because it will have a strong fish flavor. In restaurants, oil for potatoes is kept separate, but for the limited reuse in a home kitchen I don't consider this necessary. My rule is to use durable oil and no more than 4 times over the period of a month, discarding it when either has been exceeded or if it has darkened substantially. To store oil for reuse, let it be hot long enough after removing
ingredients to make sure it has no moisture (there should be no bubbling
or popping. Filter it through a cloth to remove all food particles and store
in a clean sealed jar.
RoastingRoasting usually refers to cooking birds and large pieces of meat in an oven at between 350°F and 400°F. The main source of oils is the fat contained in the bird or meat, but oil, usually Butter but sometimes Lard, Bacon Fat or Olive Oil may be brushed on, usually at the beginning or after turning. Large vegetables such as squash and eggplants may also be oven roasted, generally in a shallow pan or on a grill. If cut, they will be brushed with butter or oil.Roasting is now also used to cook small cut vegetables that were formerly fried, particularly potatoes, with little oil or fat. First they are cut to size, then tumbled with oil to coat, and roasted on a baking sheet in the oven. For larger cuts, 3/8 inch or so of water may be placed in the pan to cook the potatoes, but all will be evaporated by time roasting is done. Temperatures are not that hot so moderate temperature oils can be used. Sometimes strips of bacon or lard are draped over the meat and the fat that renders from them keeps the meat coated and moist. Once fat starts to render from the meat itself it may be used for basting (brushing or dripping) the meat itself. Always follow the instructions in the recipe unless you have a very good reason not to.
BakingThere are two basic categories of baking: baking dough products like breads, cookies, cakes, pie crusts and the like, and baking casseroles (known as "hot dish" in the U.S. Midwest). Baking casseroles may involve no more oil than a rubbing of butter on the inside of the casserole dish to minimize sticking, and perhaps some oily cheese on top. Baking breads, cookies, cakes, pie crusts and similar items always involves fats, generally fats solid at room temperature called "shortening", to provide a pleasant texture when cooled. Your choices here are generally Lard, Butter and Vegetable Shortenings (though some people have successfully (for certain values of success) used oils for some baking). For flavor and texture Lard is considered best, preferably "leaf lard" if you can get it. People trying to avoid saturated fats turned to vegetable shortening and ended up with a trans fats problem that is probably a lot worse. "Zero trans fats" vegetable shortenings are now available but are, of course, high in saturated fats - they're vegetable saturated fats though, which makes some people (especially people at Cargill and Archer Daniels Midland) feel better about them. Baking dough products is highly critical in measurement, ingredients,
temperature and timing, so follow the recipe with exacting care and use a
timer if you're likely to get distracted.
Dressing SaladsSalads is where to use those "virgin", "cold pressed" or "unrefined" oils that are high in flavor but have a smoke point too low for frying. The run-away favorite here is Extra Virgin Olive Oil - superb flavor and healthy composition both. The disadvantage of olive oil is that it solidifies in the refrigerator because it is low in polyunsaturated fats. This does no damage, just take your dressing out of the fridge 20 minutes before you need it.
Commercial salad dressings favor Safflower Oil because it is so high in polyunsaturated fats it's still liquid in the refrigerator. This sacrifices flavor compared to Olive, so they add more flavoring ingredients to make up for that. Some theories hold that polyunsaturates aren't good for you but at low salad temperatures the risk is a lot less. When making salads, you should spin the ingredients dry and then coat with oil before you add vinegar. Oil will not properly coat ingredients that are wet with water or vinegar. In any case, don't apply dressing until you're about ready to serve or the salad will wilt.
Safety
Much more serious is the possibility of severe personal injury from spilled oil or oil that splatters from contact with water. Oils are essential, but so is care.
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