Freezing food in Mason jars is an increasingly popular method of sustainable storage, but not all jars are created equal.

The general rule is that jars with straight sides are freezer-safe

Jars with "shoulders" are not.

Straight-sided jars allow liquids to expand even as they freeze, minimizing the risk of cracks or breaks. Meanwhile, jars with shoulders can trap expanding liquid, potentially causing them to shatter. This is why freezer-safe jars are typically recommended for liquids like soups, sauces, and broths.

Is It That Simple?

Here's what I learned SCOURING the Different DIY groups and Canning Forums

Many claim they've successfully used shoulder jars for years without any problems, as long as they leave enough headspace, usually about an inch, and keep the lids loose until the contents are fully frozen.

Others argue that leaving the jar open and freezing slowly prevents cracking, even for jars with shoulders. Some commenters say that both jar types are acceptable as long as common sense is applied—always leave room for expansion, and you'll be fine.

Some folks flat-out reject freezing in glass jars altogether, having experienced shattering even when following all the "rules." Others believe it's simply not worth the risk and stick to plastic or other freezer-safe containers. Ultimately, freezing success seems to boil down to personal experience and, sometimes, a little trial and error.

Despite the differing opinions, one thing is clear:

No matter which jar you choose, leaving room for expansion is crucial.

Whether you're team straight-side or shoulder, giving your liquids space will reduce the risk of a messy freezer catastrophe.