Cooking Oil

Fat is the calorie a food store runs short of first, because grains and beans have almost none and every fat goes rancid in the end. Cooking oil is 1 to 2 years sealed in a cool cupboard and a few months once opened, which makes it a rotating item, not a buried one. The field guide puts cooking oil, tallow, nut butter and shortening in the fats group, the most calories per pound of anything stored, and this page is how to keep the bottles moving and which fats outlast them.

For keeping: oils high in saturated or monounsaturated fat keep longest, which means coconut oil (5 years), olive oil (about 2 years from pressing, sealed, in dark glass or tins), and avocado oil; the polyunsaturated seed oils, corn, soybean, sunflower, canola and the generic vegetable oil, are cheaper and go rancid soonest, about a year sealed. Buy oil in the smallest bottle you will finish in a couple of months once opened, and the big tins for the sealed store. Solid fats keep longest of all: shortening (a year or more sealed, months opened), ghee (a year or more at room temperature), lard and tallow (a year cool, 2 to 3 frozen). A pressure-canned or sealed tin of lard is years.

Cool, dark and sealed is the whole method, and small bottles, because oxygen starts the clock the day the seal breaks. Keep it away from the stove, the window and the top of the fridge. For the years, sealed tins or dark glass in the coolest room, or the freezer, where oil keeps about twice as long and comes back unharmed. Oil is not a Mylar food and takes no absorber. Buy a year's oil, date it, and cook from the oldest bottle.

Smell it, do not taste it, the field guide says: rancid oil smells stale, sharp, waxy, like old paint or crayons, and the smell is unmistakable once learned. Oil that has thickened, gone sticky at the cap or darkened has oxidized. Cloudy olive oil from the fridge is fine and clears at room temperature. Rancid oil will not poison a meal but it tastes of it and the free radicals are not worth eating.

A food store wants about 20 pounds of fat per person per year as the traditional planning minimum, and more is better: a tablespoon of oil is 120 calories, and two to three tablespoons a day per person is what makes beans, rice and flatbread into enough food. Oil fries the skillet bread, dresses the beans, and makes the mayonnaise when the jar is gone. Rancid oil is not wasted: it's a lamp fuel in a wick lamp, a rust preventive on tools, and the base of a soap, which is where the book's lye comes in.

Oil needs no cold, and an opened bottle in a warm house is a few months, so finish the open ones first and leave the sealed tins. A pan of oil is also light: a wick in a jar of old oil burns for hours.

Shelf-life figures are from the Survival Foods field guide; fridge, freezer and pantry times are from the USDA cold and pantry storage charts. Run the look, smell, taste check before eating anything past its date.