Glass vs Plastic Food Storage Containers: Lids, Oven and Care Limits

A glass storage set and a plastic one can look alike on a shelf, but their care lines read very differently once you get to the oven, the microwave, the freezer and the dishwasher. This guide reads those lines on one glass set, the Pyrex Simply Store 18-piece set, using Pyrex’s product page and its use and care page, and explains what each word does and does not tell you. We did not test the containers. Where Pyrex does not state something, we say so.

The short answer

On most glass storage sets the base and the lid are two different materials, so they come with two sets of rules. For this set, Pyrex says its glassware can go in the microwave and in preheated conventional and convection ovens, while the plastic lids must stay out of conventional and convection ovens. Both can go in the freezer and the dishwasher, with the lids on the top rack (Pyrex use and care). Read the lid rules first, because they are usually the stricter ones.

What is in the set

Pyrex lists nine glass containers and nine plastic lids (Pyrex):

• Two 3-cup rectangles, about 7.5 x 5.5 x 1.75 inches
• One 6-cup rectangle, about 7.5 x 6.5 x 2.25 inches
• Two 1-cup rounds and two 2-cup rounds
• One 4-cup round and one 7-cup round
• Nine plastic lids, one for each container

Pyrex notes that all measurements are approximate and says the containers nest and stack with other Pyrex storage.

Step 1: Glass wording: tempered, borosilicate and soda-lime

Glass storage labels use a few different words. “Tempered” describes glass that was heat treated during manufacturing. “Borosilicate” and “soda-lime” are names for glass compositions. Some makers name a composition, some name a treatment, and some name both.

For this set, Pyrex describes the containers as “durable high-quality tempered glass” and says they resist stains and do not absorb food odors or flavors (Pyrex). The product page and the use and care page we read do not use the words borosilicate or soda-lime, so we do not name a glass composition for this set. If the composition matters to you, ask Pyrex before you buy.

Whatever the glass type, the wording on the box is not a promise that the glass cannot break. Pyrex’s own use and care page names three primary risks with its glass and ceramic products: breakage from sudden temperature change, breakage from impact, and burns when handling hot cookware (Pyrex use and care).

Step 2: Oven and microwave lines, base vs lid

Pyrex says its glassware “can be used for cooking, baking, warming, and reheating food in microwave ovens, and in preheated conventional and convection ovens.” It adds that decorated glass storage may discolor permanently if used in the oven (Pyrex use and care).

The same page sets clear limits for the glass:

• Preheat the oven before the glass goes in.
• No stovetop, broiler, grill, camping stove or open flame.
• No countertop appliances. Pyrex names toasters, countertop ovens, multi-cookers, electric pressure cookers, air fryers, slow cookers and rice cookers.
• Do not heat empty or nearly empty glassware in the microwave, and do not overheat oil or butter in it.

So these containers are not a dish for your pressure cooker or air fryer, or an insert for a rice cooker.

For plastic lids, Pyrex is plain: do not use them in a conventional or convection oven, or on or under a flame, broiler, grill or toaster oven. Plastic lids can go in the microwave, but Pyrex says to remove them or vent them at least 1/4 inch to avoid warping, and to open the vent if the lid has one (Pyrex use and care).

Step 3: Freezer, fridge and sudden temperature change

Pyrex says both its glassware and its plastic lids can be used in the refrigerator or freezer. The limit is the jump between extremes. Pyrex says not to transfer glass directly from the freezer to a hot oven, and to let hot glass cool before washing, refrigerating or freezing it (Pyrex use and care).

Its other temperature-change rules for hot glass:

• Do not add liquid to hot glassware.
• Do not set it on a wet or cool surface, directly on a countertop or metal surface, or in the sink.
• Do not handle it with a wet towel or wet potholder.
• Let it cool on a cooling rack, a dry potholder or a dry cloth.

These are Pyrex’s rules for Pyrex glassware. Another brand may list different limits, so read the sheet that comes with your set.

Step 4: Lid material and BPA-free wording

Pyrex lists the lids as plastic and words the claim this way: “BPA-free plastic lids are top-rack dishwasher, freezer and microwave safe” (Pyrex). That is Pyrex’s statement about its own lids. The product page we read does not name the type of plastic.

A BPA-free line is a maker’s claim, not an FDA mark. FDA’s Packaging & Food Contact Substances page points to its food contact substance notification program, its inventory of food contact substances listed in 21 CFR, and guidance for industry. It does not list or rate consumer brands, so the page will not confirm a product’s BPA-free wording for you.

Pyrex also says to take care with tomato and acidic sauces, which can stain plastic lids, and, if a lid has a removable seal, to check that it is in place to prevent leaks (Pyrex use and care).

Step 5: Dishwasher and cleaning rules

Pyrex says its glassware can be washed in the dishwasher or by hand, loaded so it does not bump other items during the cycle. Plastic lids go on the top rack. Use non-abrasive cleansers, and if you need to scour, use only plastic or nylon pads, never metal or other hard objects. Before first use, Pyrex says to wash in warm soapy water and let the glass and lids dry completely before adding food (Pyrex use and care).

Pyrex also says not to use glass that is broken, chipped, cracked or severely scratched, and not to strike utensils against it.

Step 6: Read a plastic set the same way

We do not have an all-plastic set in our catalog, so this step is about what to look for rather than a specific product. Put the same questions to any plastic container label:

• Which parts does the maker call microwave safe, and does it ask you to vent the lid?
• Are freezer and dishwasher lines given, and is the rack named?
• Is any oven use listed? If the label does not mention the oven, do not assume it is allowed.
• Does the maker name the plastic, and how exactly does it word any BPA-free claim?
• How long is the warranty, and does it cover lids as well as bases?

Lining up two sets this way usually tells you more than the words glass or plastic on the front of the box.

Warranty and what owners mention

Pyrex lists a 2-year limited warranty on the glass containers and plastic lids (Pyrex). Customer reviews on the same Pyrex page are mixed: one reviewer reports that the lids split within two months, another that items arrived broken, and another found the containers smaller than expected but was glad to switch to glass. These are owner reports, not our testing.

A quick checklist

1. Read the lid rules separately from the base rules.
2. Check the oven line: preheated oven only, and lids out.
3. Vent or remove plastic lids in the microwave.
4. Never go straight from freezer to hot oven.
5. Note the dishwasher rack for lids.
6. Read any BPA-free or glass-type wording as the maker’s own claim.

FAQ

Can the Pyrex Simply Store lids go in the oven?

No. Pyrex says not to use plastic lids in a conventional or convection oven.

Can I move the glass from the freezer to the oven?

Not directly. Pyrex says not to transfer glass from the freezer to a hot oven, and to preheat the oven before the glass goes in.

Is the Pyrex Simply Store set borosilicate glass?

Pyrex calls it tempered glass. The pages we read do not say borosilicate or soda-lime.

Can I microwave with the lid on?

Pyrex says to remove plastic lids or vent them at least 1/4 inch to avoid warping.

Where to go next

For more kitchen gear read spec by spec, see our salad spinner specs explainer and our kitchen tools buying guide, or browse all kitchen tools.