25.6 Freezing

The cold-storage rules

The freezer must hold food at −18°C (0°F) or colder. Freezing does not kill most bacteria: between 0°C and −18°C, most bacteria survive but do not grow. If the freezer warms above −18°C, food can lose color and vitamins, and cooling it down again does not undo the harm.

• Wrap well. Anything not properly wrapped gets freezer burn: it loses moisture, and its texture and flavor suffer. Look for dry white or gray patches on the surface. Meat is especially prone to it.
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• Rotate. Use the oldest stock first (first in, first out). Chest freezers make this hard, because old stock must come out before new stock goes in.
• Count the cost. Frozen fruit and vegetables, well wrapped, keep for months, and so do well-wrapped meat and fish. Freezing fresh produce in the kitchen takes time and may cost too much, and fresh fruit that is not properly prepared will not freeze well.
• Cook with care. Partly frozen meat or poultry can have cold spots that do not cook through. Allow more time and check the inside temperature.

Frozen storage in general is covered in the food safety chapter. see chapter 2: Frozen storage

Freezing fast

To freeze food well:

• Freeze it as soon as it is ready.
• Keep packages apart, not stacked or touching, until they are frozen solid; only then stack them.
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• Label every package with the food, its treatment and the date.
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• Press the air out of bags and seal them tight.
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• Pack small bags together inside a larger freezer bag for protection.

Some of the methods below do not give a standard product; that is the point of trying them.

Fruit: apple slices

Freeze apple slices six ways and compare them:

• dry, with no treatment
• with dry sugar
• steamed 3 minutes
• in a 35% syrup
• in the syrup with a commercial anti-darkening product
• in the syrup, with the fruit sprinkled with lemon juice

For the 35% syrup, boil 2 cups of water with 1 cup of sugar at a rolling boil, then chill it before adding anything else. To judge them, thaw the sealed bags in lukewarm water for 20 minutes.

Vegetables: blanch first

Freeze cauliflower and carrots both blanched and unblanched, and compare them with fresh and canned.

• Wash the vegetables, peel the carrots, and slice or chop.
• Bring at least 1½ quarts of water to a boil for each cup of vegetable. Lower the vegetable in, cover, and keep the heat on high.
• Time from the moment the vegetable goes in: carrots 2 to 3 minutes, cauliflower 3 minutes, or until hot in the center.
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• Lift out with a slotted spoon and chill at once in at least 2 quarts of iced water. Drain well when cool.
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• Bag, press out the air, seal, and freeze at once.
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Prepared foods

Prepared dishes can be frozen too, to show what freezing does to them.

• Fruit pie. One pie is baked, cooled, wrapped in plastic wrap and foil, and frozen; one is frozen unbaked, with no vents cut. The unbaked pie is thawed overnight in the refrigerator, vented, baked at 450°F for 15 to 20 minutes, and finished at 375°F for about 20 to 30 minutes. The baked pie is thawed overnight in the refrigerator and warmed at 350°F for about 35 to 40 minutes, loosely covered with foil so the top does not brown too much.
• Gelatin and cornstarch pudding are frozen in covered plastic containers and compared with fresh. Do not use instant pudding mix.
• Casseroles. For Spanish rice, and for macaroni and cheese, the rice or pasta is cooked slightly short of done, and the dish is frozen unbaked. The frozen Spanish rice bakes covered at 350°F until it bubbles at the edges, about an hour; the macaroni and cheese bakes uncovered in a water bath at 350°F for about 50 to 60 minutes. Some baking dishes cannot go straight from freezer to hot oven; with those, do not preheat the oven.
• Spice cake. One pan of batter is frozen raw and one is baked and then frozen. The frozen batter is thawed overnight in the refrigerator and baked at 350°F for 20 to 25 minutes; the frozen cake is warmed in a heat-proof wrap at 300°F for about 15 to 25 minutes.
• Egg salad is frozen to show what happens to cooked egg white and mayonnaise.
• Ground beef patties are frozen raw and cooked. The recommended wrap is plastic wrap and then foil; wrapping in non-freezer plastic wrap or a bag is not recommended.
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Reheating safely. Food being reheated has to get to 74°C (165°F) or hotter and stay there 15 seconds or more, and on a stove or in an oven it must get there within two hours. Ground meat must be cooked to 70°C (158°F). Cook the beef patties fresh or from the freezer, and reheat the cooked frozen ones to 165°F. Reheat leftovers only once.