Freezing food is a very effective way of sealing in nutrients and cutting down on food waste in your house. The main downside, of course, is freezer burn, when cold, dry freezer air pulls the moisture out of your food—and the taste along with it. Freezer-burned food isn't harmful to eat, but the "burn" creates unpleasant texture, nutrient loss, and often goes hand in hand with the absorption of off-flavors pulled out of other items. Most of us usually wind up throwing out freezer-burned food, undoing efforts made to eliminate food waste.
The remedy? Airtight, puncture- and tear-resistant packaging with as little air trapped inside as possible. Plastic bags and containers fit the bill perfectly, but not if you're trying to cut plastic out of your life to avoid being exposed to harmful chemicals like hormone-disrupting bisphenol A, and also to avoid single-use disposable plastics that live forever in a landfill. So what should you use instead? There are a lot of good alternatives that work for freezing, including aluminum foil, glass containers and mason jars, and butcher or wax paper.
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 a storage set 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 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 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 unimpeded expansion in any jar whose neck is narrower than the body of the jar. 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.