We’ve all used Pyrex glass cookware in our ovens before, but knowing why Pyrex glass is oven-safe is less common. Can glass go in the oven no matter what kind of glass it is? Or is Pyrex special? These are important things to know if you want to avoid some pretty messy mistakes.
It turns out there are different kinds of glass, two of which are normal (annealed) and tempered. Tempered glass has undergone a special process to make it stronger and able to withstand higher temperatures, so it can be baked in the oven without incident. Normal glass, on the other hand, is too weak to handle oven temperatures and will shatter.
Think of this article as your comprehensive guide to using glass in the oven: we’ll cover the safety concerns and temperature limits, and we’ll show you how to tell whether the glass is oven-safe or not. We’ll even cover some baking tips and our recommendations on the best oven-safe glass cookware sets.
- Is it Safe to Put Glass in the Oven?
- Highest Temperature You Can Put Glass in the Oven
- Can Glass Shatter in the Oven?
- How Do I Know if Glass is Oven-safe?
- Is it Better to Bake Cake in Glass or Metal?
- 5 Best Glass Bakeware Sets to Use in the Oven
Is it Safe to Put Glass in the Oven?
As mentioned in the introduction, there are different kinds of glass you’ll commonly find in any household. One is ordinary glass used to make decorative plates, ornaments, and the glasses we drink out of. The other is tempered glass (or toughened glass) which has been specially treated to make it about four times stronger than ordinary glass.
Tempered glass can withstand oven temperatures up to about 400F, and is generally tougher than normal glass. Sometimes also referred to as safety glass, tempered glass has many applications such as car glass, shower cubicles, aquariums, and mobile phone screen protectors. And, of course, it is also used to make glass cookware!
The third kind of glass is borosilicate glass. Since the 1920s, this kind of glass has commonly been referred to by the name of the brand that introduced it into the commercial market: Pyrex. Unlike tempered glass which gains its strength through special treatments, the strength of borosilicate glass comes from the materials it is made from.
Quick side note: nowadays, a lot of Pyrex products are actually made out of soda-lime glass, not borosilicate. Soda-lime glass is another kind of heat-resistant glass, but it’s much cheaper to produce.
The most important thing to remember is that only tempered glass and borosilicate glass are safe to go in the oven. All other glass will not be able to handle the heat and will shatter. All normal glass cannot go in the oven.
Highest Temperature You Can Put Glass in the Oven
The maximum temperatures of both borosilicate and tempered glass can vary depending on the manufacturing process and the quality of the brand. You’ll find oven-safe glass products with temperature limits of anything between 300-500F.
The best way to know the precise temperature limit of your glass cookware is to check the glass container itself, its packaging, or its user manual. If you’re unable to find out, the safest thing you can do is not subject it to temperatures higher than 300F.
Normal glass, on the other hand, cannot handle any kind of hot oven temperature. Placing non-tempered glass into a preheated oven would likely cause it to shatter almost instantly. If it isn’t labeled as oven-safe, the best thing you can do is not put it in the oven.
Can Glass Shatter in the Oven?
Glass can indeed shatter in the oven. This will almost certainly happen to normal glass that is incorrectly placed into an oven, but it can also happen to oven-safe glass in extreme circumstances.
All kinds of glass can also shatter outside of the oven when subjected to sudden temperature changes. This could include taking a glass pan from the fridge and putting it straight in the oven, or vice versa. But with non-tempered glass, it can also happen in far less extreme circumstances.
Drinking glasses that are taken out of a hot dishwasher and immediately have an ice-cold drink poured into them, for example, can also shatter. When glass shatters, the cracks travel through the surface of the glass at the speed of sound, so the process happens extremely quickly and can be a bit of a shock, especially if you’re holding the glass when it happens.
Different kinds of glass require different kinds of care, so make sure to read up on how to look after them.
How Do I Know if Glass is Oven-safe?
In some cases, finding out whether your glass is oven-safe or not will take all of about 3 seconds, but in other cases, it is unfortunately not so easy. Let’s take a look at the various things you can do to find out if your glass is safe to go in the oven.
1 – Look at the product
The first and easiest way to find out if your glass can go in the oven is to look for a symbol indicating so on the product itself. This information is usually found on the bottom of glass containers: various symbols will show whether the glass dish is oven-safe, dishwasher-safe, or microwave-safe, for example.
Sometimes, writing is used instead of symbols. If your glass product says ‘oven-safe’, ‘tempered glass’, or ‘safety glass’, then it will be safe to go in the oven. It may also have the maximum temperature listed.
Similarly, some products will explicitly state that they are not oven-safe, so if you see a symbol or writing that indicates this, then you cannot use your glass dish in the oven.
Finally, if your glass dish says nothing, that tends to be a sign that it may not be oven-safe. But, it’s too early to give up just yet, so let’s move on to the next method!
2 – Check the packaging
If your product is blank, your next best bet is its packaging. That might be the box it came in, or simply a label it had attached to it. Packaging is used to advertise a product, so it will generally show off all the wonderful things it can do: including being oven-safe.
Check all sides of the packaging, for the words mentioned before: ‘oven-safe’, ‘tempered glass’ and ‘safety glass’ or keep an eye out for temperature limits.
If you don’t find anything, move on to tactic no. 3!
3 – Check the user manual
If your product came with any kind of literature detailing how to use it or look after it, this is another place you can look. As before, look out for the key words we mentioned, and for any mention of temperatures. If your product does have a manual, it should almost definitely be written whether or not the glassware can go in the oven.
If your product didn’t come with a manual or you don’t have access to it anymore, you are left with one last thing you can try.
4 – Google it
When all other options have been exhausted, the last resort is to take all the information you have on the product: its brand, its name, where it was bought, etc, and type it into Google.
Modern and popular brand names will definitely have product information published online, it’s just a matter of finding the entry that matches your product.
If your glassware is old or you bought it at a thrift store, then you’re far more unlikely to find the information you need.
Other Things to Watch out for When Putting Glass in the Oven
If your glass dish really is from the junk store, there are other reasons that you may need to avoid putting it in the oven.
When oven-safe glass gets old, it can lose its strength and become scratched and chipped. When the surface of the glass is damaged, it affects the product’s ability to withstand heat and can lead to the glass shattering in the oven. This applies to all oven-safe glass pans, even if you didn’t buy them second-hand!
Glass dishes don’t have to be old to get chipped, it can, unfortunately, happen at any point—sometimes it will even happen in the dishwasher. When this happens, your glass dish is unfortunately no longer suitable for being used in the oven, even if it is new. A glass baking dish will not be able to handle the heat from the oven and will be subjected to thermal shock, which will end in the glass breaking.
Glass Products that are Not Oven-safe
To save you a bit of time, here is a list of common glass products that almost definitely won’t be oven-safe. Normal glass breaks when it goes in the oven, so make sure not to put any precious pieces of decor in there.
- Drinking glasses
- Mason jars (this is a debated topic, but at the very least, not all mason jars are tempered)
- Decorative thin glass items
- Glass bottles
- Glass mugs
Is it Better to Bake Cake in Glass or Metal?
You may be wondering which is better to bake a cake in: an oven-safe glass container, or a normal metal cake pan. The answer depends on what kind of cake or dessert you intend to bake.
The main difference between a metal cake pan and a glass pan when it comes to baking is the way the materials heat up and cool down. Metal heats up quickly and cools down quickly, whereas glass pans heat up slowly and retain heat for longer.
The result of this is, however, slightly unintuitive. Despite heating up more quickly, metal pans actually bake the cake more slowly and evenly than glass pans. Metal pans can also be made in a greater variety of shapes and can create sharper corners that look really great on a sheet cake compared to the rounded corners of glass dishes. Glass bakeware will bake the outsides of your cake very quickly, but often leave the middle undercooked which can be problematic.
However, that same glass container will be perfect for cooking savory dishes like pasta bakes, or desserts like a fruit crumble. The heat retention ability of the glass will also keep your food warm inside the pan which can be great when you want to leave the pan on the table so people can grab extra servings.
Another reason we recommend baking a fruity dessert like a fruit crumble in a glass pan is that metal can actually react to the acids in the fruits and alter the taste. Glass containers won’t do this, so they are much better suited to baking with fruits.
Overall, for baking classic sponge cakes, metal pans are often considered the better option for a better-looking, more evenly baked cake.
5 Best Glass Bakeware Sets to Use in the Oven
If you haven’t used glass to bake with before, take a look at our list of the 5 best oven-safe glass bakeware sets. You’ll be able to use these sets at a high temperature without worrying about the glass breaking.
1. Anchor Hocking Basic Set
This basic set by Anchor Hocking has everything you need to start baking: mixing bowls, casserole dishes, smaller glass bowls, and other cookware. They are made from strong glass which has been tempered and treated to withstand temperatures of up to 425F.
Although this is oven-safe bakeware, it’s best to avoid putting the glass through rapid temperature changes as this can weaken it and shorten its lifespan. Glass dishes do not have non-stick surfaces, so they should be soaked after use to make them easier to clean.
This set includes 10 pieces of cookware that can be used to bake, store and display foods. The oven-safe dish will retain heat for a long time, perfect for keeping food hot at the table. It will take a long time to completely cool, so make sure to use oven mitts when carrying the hot glassware.
2. Pyrex Bakeware and Storage Set
The famous Pyrex brand has been trusted by households for 100 years, and its products come with a two-year warranty. This 8-piece set includes plastic lids so you can use the casserole dish to store food in the fridge once it has cooled to room temperature. If you subject the dishes to extreme temperature changes, you could make the glass break, so make sure to let it cool down before putting it on the cold surface of a fridge.
To use the glass safely, follow the instructions Pyrex will include with your set when heating food and using the products with high temperatures.
Pyrex products are also preheated oven-safe, meaning they can withstand the sudden temperature change when going from room temperature to the heat of a preheated toaster oven.
3. Libbey Baker’s Basics Set
The Libbey baker’s basics set includes 5 pieces: a 9-inch x 13-inch glass baking dish, a 8-inch x 8-inch glass baking dish, a 9.5-inch glass pie plate, a 2-quart glass mixing bowl and a 2-quart round glass casserole dish with a glass cover.
The glassware is tempered and able to withstand sudden temperature changes, allowing it to be used in the oven, the microwave, the fridge and the freezer. Putting glass in the oven is safe as long as you follow the instructions—to read about the temperature limit and care manual for these products, visit the Libbey brand website.
4. Finedine 4-piece Set
If you like statement pieces, this Finedine set features 4 casserole dishes with a unique design and shape. Although these dishes can be used in the oven, the microwave, the fridge, the freezer, and even the top rack of the dishwasher, Finedine recommends avoiding thermal shock through extreme temperature changes.
The largest casserole dish is 15.5 x 10 inches, and the set of four nests within each other for convenient storage. The design also features easy to hold handles so you can remove the glass containers from the hot oven safely.
5. Amazon Basics Set of 2
If you’re not looking for a larger set just yet, this Amazons Basics set of 2 oven-use glass dishes has everything you need to try out using glass in the oven. The temperature limit for this set is listed at an incredibly high 1076F and claims to be able to handle even extreme temperature changes.
These glass containers are made from very thick glass which is why they can withstand high temperatures.
Putting glass in the oven is generally fine as long as you stick to reasonable temperatures and make sure the glass containers are clearly listed as safe for oven use.
Glass breaks when subjected to sudden changes in temperature, so it’s best not to put a hot dish into a fridge, or put cold glass straight into the oven. Cracks and chips can also break glass dishes when they are subjected to uneven temperature, so make sure to check your glassware for damage before use.
Glass containers are great for cooking casseroles, pasta bakes, and fruit desserts, and they can also be used to store food too. If you like using glassware for lots of different things, it might be a good idea to have all of your glass containers be oven-safe, so you don’t need to worry about using the wrong type!