Quick Answer

Yes, Glasslock oven safe containers are freezer safe. The tempered glass is designed to handle extreme temperature changes, but you still need to follow a few simple rules to prevent cracking. Always cool food before freezing, leave headspace for expansion, and thaw gradually in the refrigerator.

If you meal prep or batch cook, you've probably wondered whether your glass containers can go straight from the freezer to the oven. The good news: Glasslock oven safe containers are freezer safe, thanks to their tempered glass construction. But 'freezer safe' doesn't mean you can ignore basic handling rules.

In this guide, we'll cover how to freeze and thaw Glasslock containers without breaking them, what to avoid, and which sizes are most practical for freezer storage. By the end, you'll know exactly how to use your Glasslock containers for freezer meal prep with confidence.

Why Glasslock Containers Are Freezer Safe

Glasslock oven safe containers are made from tempered glass, which is treated to withstand rapid temperature changes. This is why they can go from the oven to the freezer (and back) without shattering. The glass is durable, but it's not indestructible—thermal shock can still occur if you expose it to extreme temperature swings too quickly.

The key is to manage temperature transitions. For example, placing a hot container directly into the freezer can cause stress cracks. Likewise, taking a frozen container straight from the freezer into a hot oven is risky. Always allow the glass to come closer to room temperature before changing its environment.

  • Always cool cooked food to room temperature before freezing.
  • Leave at least 1 inch of headspace in the container to allow food to expand.
  • Never place a hot container in the freezer or a frozen container in a hot oven.

How to Freeze Food in Glasslock Containers

Start with completely cooled food. Hot or warm food raises the temperature inside the freezer and can cause condensation, which may weaken the seal. Use a container with a tight-fitting lid to prevent freezer burn and odor absorption.

Fill the container only about three-quarters full. Liquids expand when frozen, so leaving room is crucial. For soups and stews, this is especially important. Once filled, snap the lid on securely and place the container in the freezer. Avoid stacking heavy items on top of the glass while it's still cold.

For portion control, choose smaller containers like the Glasslock Oven Safe Square 1.5 cups or the Round 0.7 cups. These are perfect for single servings and thaw quickly.

  • Use smaller containers for individual portions to speed up thawing.
  • Label containers with the date and contents before freezing.
  • Freeze flat if possible to save space and ensure even cooling.

How to Thaw Glasslock Containers Safely

The safest way to thaw frozen Glasslock containers is in the refrigerator. This gradual process prevents thermal shock and keeps food at a safe temperature. Depending on the size, it can take several hours or overnight.

If you're in a hurry, you can thaw in cold water. Place the sealed container in a bowl of cold water and change the water every 30 minutes. Avoid warm or hot water, as the sudden temperature change can crack the glass.

Once thawed, you can reheat the food in the same container—Glasslock is oven safe. Just remember to remove the lid before placing it in the oven, and follow the manufacturer's temperature guidelines.

  • Never thaw in hot water or in the microwave without removing the lid.
  • For quick thawing, use the cold water method with frequent water changes.
  • If you plan to reheat, thaw in the refrigerator first to avoid temperature shock.

Common Mistakes to Avoid

One of the biggest mistakes is putting a hot glass container directly into the freezer. This can cause the glass to crack due to rapid contraction. Always let food cool completely before freezing.

Another mistake is overfilling. When liquids freeze, they expand, and if there's no room, the pressure can crack the glass or pop the lid. Always leave headspace.

Finally, don't use glass containers that have chips or cracks. Damaged glass is more susceptible to breaking under temperature stress. Inspect your containers regularly and replace any that show signs of wear.

  • Never stack frozen containers with heavy items on top.
  • Avoid using containers with any visible damage.
  • Always remove the lid before heating in the oven or microwave.

Diagnosis: Is Your Freezing Method Safe?

  • Symptom: You're unsure if your Glasslock container can go in the freezer, or you've heard stories of glass cracking. Glasslock containers are freezer safe, but only if you follow proper procedures.
  • Likely cause: Most cracking happens because of thermal shock—placing hot glass in the freezer or frozen glass in hot water or a hot oven. Always cool food completely and thaw gradually.
  • Corrective action: Cool food to room temperature, leave headspace, seal the lid, freeze, and thaw in the refrigerator or cold water. Follow these steps to keep your containers intact and your food safe.
  • Stop or choose another option: If your container is chipped, cracked, or you're planning to use it in a microwave without a vented lid, stop and switch to a different container or method. Damaged glass is not worth the risk—replace it.

Glasslock Containers for Freezer Use

  • OCST-040 Glasslock Oven Safe Square 1.5 cups: 12 oz. Glasslock® Square 1.5 c. 4-1/2′′ sq. x 2-1/4′′ h This compact size is ideal for single servings of soups, sauces, or leftovers. It freezes and thaws quickly, making it a practical choice for meal prep.
  • OCST-090 Glasslock Oven Safe Square 3.3 cups: 26.4 oz. Glasslock® Square 3.3 c. 5-3/4′′ sq. x 2-3/4′′ h With a larger capacity, this container is great for family-sized portions or batch cooking. It also fits well in most freezer shelves and stacks neatly.
  • OCCT-019 Glasslock Oven Safe Round 0.7 cups: Glasslock® Round 0.7 c. 3-3/4′′ diam. x 1-3/4′′ h Perfect for small portions like baby food, sauces, or herbs. Its round shape makes it easy to stir and reheat, and it takes up minimal freezer space.
  • Glasslock Oven Safe Square 6pc set: Square 6pc Set 1pc – OCST 040 _ 1.5c 1pc – OCST 090 _ 3.3c 1pc – OCST 165 _ 6.0c + 3 matching lids This set gives you a range of sizes for all your freezer needs, from single portions to large casseroles. It's a cost-effective way to start your freezer meal prep.

Glasslock oven safe containers are excellent for freezer storage when used correctly. By cooling food before freezing, leaving headspace, and thawing gradually, you can enjoy convenient, safe meal prep without worrying about cracks. Choose the right size for your portions, and you'll have a reliable freezer-to-oven solution for years to come.