Whether you plan on freezing leftovers or following a “freezer style” recipe, there are some questions that usually come to mind. This post will teach you how to safely freeze in Mason jars.
It is important to only freeze in jars that do not have shoulders (jars that are straight sided or “tapered”) are the easiest because the contents can expand upward in the jar during freezing, especially if you’re freezing liquids (jams, jelly, soup, broth, etc).
You can use other food grade jars, as long as the expansion of the food isn’t a problem. We often freeze single serving sizes of grilled chicken, beef BBQ, or meatballs in other jars since the straight sides really aren’t a requirement.
Jars with necks (sauce & woozy bottles etc.) are not recommended, as the contents will expand upward into the part of the glass with a smaller diameter causing breakage. If the description of the jar doesn’t mention that it is safe for freezing, double check with your supplier. The chart below indicates Ball jars that are freezer safe.
You’ll want to use a lid with a plastisol liner or a foam liner to create a good airtight seal. This is a great time to re-use your already spent flat canning lids or single piece lids because all you need is a good seal to keep flavors in and air out! The single piece lids are nice for jams and products that you will be getting into often. You may also use the plastic lids with a foam liner.
Ball also has a leak proof storage lid for wide mouth and regular mouth canning jars. These lids are not for preserving, but are designed specifically for food storage, and are great for the freezer.
Another great lid option – iLids Storage Lids – they come in a wide variety of colors, which is very useful if you want to be super organized and color code your freezer items.
Allow enough headspace for the expansion of your product. Some, but not all of the Ball jars have a “FOR FREEZING——FILL HERE” line embossed on the glass. We refer to this as the ‘freeze line’. A general rule of thumb for any jar is to only fill to a little below the collar of the jar, or only to the freeze line if that’s indicated on the jar.
Allow enough headspace for the expansion of your product. Some, but not all of the Ball jars have a “FOR FREEZING——FILL HERE” line embossed on the glass. We refer to this as the ‘freeze line’ pictured above. A general rule of thumb for any jar is to only fill to a little below the collar of the jar, or only to the freeze line if that’s indicated on the jar.
Remember most food grade glass exhibits a 90-degree thermal shock differential! Jars should not be subject to an abrupt temperature. Keep this in mind for both when filling your jars to freeze, and thawing your jars filled with frozen contents.
For example: When canning, you can’t pour hot contents into a cold (or sometimes even room temperature) jar. For the same reason, you shouldn’t expose your jarred frozen items to sudden heat.
To fill your jars, be sure to start with clean, room-temperature jars (around 70-degrees). Fill jars with product that has cooled to 160-degrees, then let cool to room temperature before placing jars in your freezer.
To safely defrost jars, set them on a dish towel or paper towel on a plate or tray (to hold/absorb the melting condensate) and allow thawing in the refrigerator overnight, or on your counter if you are able to monitor them. If you need to speed up the process, you may set them in a few inches of lukewarm water. Do NOT try to microwave a frozen jar.
For more details about freezing foods safely, read these posts: