Metal And Glass Containers
These are the best choices for plastic-free freezing, especially if you are going to keep the food frozen for months before use. Flat, rectangular containers are the easiest to stack and also make the best use of freezer space. Just look for ones with silicon lids or lids with silicone gaskets, to ensure you get an airtight seal that will keep food fresh. Pyrex makes storage containers with glass lids that have airtight silicone seals, but for the most part, glass storage containers have plastic lids. One Korean company is making glass containers with stainless steel lids as well as 100-percent stainless steel freezer containers. If you're really dedicated to cutting down on plastic, you can replace plastic lids with these Silikomart Coverflex reusable freezer-safe silicone lids. But these storage products are not cheap. So unless money is no object, you may need to explore other options. For instance, freeze the food in a glass container until solid, then remove the block of food from the container and wrap it tightly in something else before returning it to the freezer (see below for options). Then you can reuse the same glass container for something else.
Glass Canning/Freezing Jars
These tapered wide-mouth Mason jars, usually described as quilted crystal jelly jars, are specifically designed for freezing and come in pint and half-pint sizes. They're a good choice for vegetables and fruits, and are much more affordable than glass or metal boxes, though less easy to pack tightly in the freezer. Use standard metal two-piece canning lids, which seal well, unless you're bothered by the fact that the coating on them contains a small amount of BPA. Tattler makes reusable BPA-free canning lids, but they are a hard, though probably reasonably safe, plastic. So pick your poison. You can also freeze in standard canning jars, but you need to leave more headroom over liquids to allow for expansion. Don’t try to freeze liquids in jars other than Mason jars. They will burst, as even Mason jars do occasionally.
If you're using either glass jars or glass food containers, it helps to add ¼ inch of water over the frozen food after it is solid to help provide a temporary seal protecting the food from the air. Rinse the ice layer off with warm water before defrosting the rest of the jar's contents.
Related: 8 Crafty Ways To Upcycle Mason Jars
Some commercial frozen foods still come in waxed cardboard boxes. If you can find empty ones for sale, they are a reasonable option, but be sure to tape the openings tightly with freezer tape, a special, thick type of masking tape designed to withstand the cold temperatures of your freezer. You can also make your own waxed boxes by reusing cartons or aseptic containers (the kind boxed soup comes in). To do that, carefully cut the top seam, open the container completely, and wash it out well. Fill it with the food to be frozen, leaving enough space to be able to fold the top over and seal it securely with freezer tape. And label it! You can't see through boxes the way you can with glass jars, so don't rely on memory to remind you of what's inside.
Paper And Foil
Wraps are good for chunks of firm foods such as meat or pre-frozen blocks of food (see "Metal and Glass Containers," previous page). Unbleached brown butcher paper can be used in the very short term or as a first-layer wrap, but it provides very little protection from moisture loss. Waxed paper is a bit more moisture resistant and will work for a few weeks. Look for unbleached products like Natural Value Unbleached Waxed Paper or Waxed Paper Bags. Butcher and waxed paper are also good wraps for cheeses that you want to take out of plastic wraps and store in your refrigerator; just follow the same instructions for wrapping food, below.
Heavy-duty aluminum foil is probably your best bet—airtight when well sealed and moisture-resistant. It can be damaged easily while you handle it, though, and once there's a hole, it's Freezer-Burn City. Wrap meats carefully in foil, and then overwrap with butcher or waxed paper to protect it (if you're careful with the paper, you can probably reuse it a few times), and be sure to recycle the foil when you're finished with it.
Whether using paper or foil, to wrap food properly, cut a piece large enough to wrap all the way around the food, plus a couple of inches extra. Place the food in the center, bring two opposite edges together, and roll them down until the rolled edge is snug against the food; flatten the rolled edges, and tape down securely with freezer tape. Flatten the extra wrap at one end, fold in the corners to make a point, fold that up snugly over the taped seam, and tape. Flatten the remaining loose end and repeat, squeezing out as much air as possible as you go. For anything you plan to keep longer than a few weeks, repeat with a second length of wrap.
More and more silicone products that are great for freezing have been introduced, which is great. Silicone is sturdy, reusable, and as airtight and puncture- and moisture-resistant as plastic. Plus, it's more durable and doesn't come with all the associated health risks. Norpro Silicone Stretch bowl covers are stretchy sheets of silicone you can use to seal the tops of bowls or baking pans with. The largest of the sheets is 10"-x-10" but stretches to twice its size, so it should cover a pretty big container. And—Eureka!—Lekue has (finally) introduced what is, in my mind, the holy grail of freezer containers: a 1-liter, zip-close silicone pouch! I’m hoping they will come out with a larger size as well.
Admittedly, these silicone products are a bit pricey for my nickel-pinching self, so it's going to be a while before I rely on them as my only tools in the freezer. If you want a more affordable option, plastic freezer bags, ever airtight and long-lasting, can be handy kitchen helpers, despite their somewhat iffy raw material. Opt for "freezer bags" (not "storage" or "sandwich" bags, which are much thinner). Most are made with a type of plastic that does not contain BPA, but if you don't like the idea of your food touching plastic, you can wrap it first in waxed or butcher paper, then put it in a plastic bag. Also, biobased plastic bags and wraps made from corn and sugar are available online and in some stores; I've yet to try them for freezing, and there's some controversy over whether they're actually greener than regular plastic, considering that they take a lot of energy to make, not many cities compost them, and they won't break down in the average home compost pile. I'd opt for these as your last resort.