No, not all glass jars are freezer safe. The ability of a glass jar to withstand freezing temperatures depends on its quality, thickness, and design. Generally, glass jars that are specifically labeled as "freezer-safe" or "safe for freezing" are designed to withstand the low temperatures of the freezer without shattering or cracking.
Regular glass jars, such as those used for canning or storing food, may not be suitable for freezing. The main concern is that when liquids freeze, they expand, and this expansion can put pressure on the glass, causing it to break or crack. Additionally, certain types of glass, like thin or low-quality glass, are more susceptible to damage from extreme temperature changes.
To ensure that a glass jar is freezer safe, look for labels or manufacturer instructions indicating that the jar is suitable for freezing. If you're unsure about a particular glass jar, it's best to err on the side of caution and avoid using it in the freezer. Instead, consider using containers made of materials specifically designed for freezing, such as freezer-safe plastic containers or glass containers specifically rated for freezing.