1. Go heavy. Always use freezer-specific, moisture-proof plastic bags, containers, and heavy-duty freezer foil. Even several layers of lighter weight options, like regular plastic wrap, won’t protect food adequately.
2. Remove air. Air draws out foods’ moisture and creates frost, causing nasty freezer burn and ice crystals. If food is in a large container (such as a casserole), transfer to the smallest receptical that will work and cover tightly with a lid or heavy-duty foil. With freezer bags, use a straw to suck out as much air as possible; or invest in a vacuum sealer (about $100), which protects food, including raw meats, for up to a year.
3. Be square. Cubical containers take up less room than rounded ones. Leave about a 1/2 inch of space at the top for liquids to expand when freezing. And don’t forget to label containers with the contents and date.
4. Spread out. Freeze small, loose foods, such as berries, blanched asparagus, meatballs, and ravioli, in a single layer on a baking sheet. When solid, transfer to freezer bags.
5. Go flat. Pour soups, stocks, purées, and sauces into heavy zip-top bags, squeeze out any excess air, and freeze flat. When solid, stack and store horizontally or vertically to save freezer space. Because of increased surface area, these will also thaw quickly in a bowl of warm water.