Cooking with certain materials can be a challenge, because it is difficult to know what is safe to use and what isn’t.
A material might be safe for one method of cooking but not for others; it is sometimes even the case that some food containers are suitable for cooking with, while others made out of the same material are not.
There is usually no quick way of knowing if a container can be used to cook with, just going by what it’s made from.
One of the most common questions encountered in cooking is whether glass is suitable for heating foods in the oven. In stores, you will often come across large glass dishes that are designed for things like roasting meats and potatoes – surely this means that glass is fine to use in an oven?
Not necessarily: while some glass products are made for this purpose, others are not, and you don’t want to end up unknowingly using something that isn’t safe. Therefore, it is best to check every time to avoid any cooking accidents and make sure you’re using your equipment properly.
What Sort Of Glass Can Go In The Oven?
For glass to be considered oven-safe, it needs to have been tempered first. Tempering is the term given to the process of reinforcing glass via chemical or thermal treatments, resulting in a more useful, hard-wearing material. After the glass has been treated, the outer surface is in a state of compression, while the inner part remains in tension.
This makes it up to 5 times stronger than untempered glass, which is in tension all the way through and thus requires less pressure to break. Tempered glass is also far more heat-resistant than its regular counterpart.
Tempered glass is used for a variety of different purposes, not just culinary ones. You will find tempered glass in construction, vehicle manufacture, and technology, as it is a common material for making windows, vehicles and cell phone screens. Unfortunately, having tempered glass alone is not a guarantee that it won’t crack, as all glass can succumb to environmental stresses.
Indeed, tempering alters the way in which glass shatters, causing it to break into granules rather than sharp pieces. It is safer overall, but you should still handle it with as much care as you would a fragile glass ornament.
In response to common frustrations about glass breaking in the oven after a single use, a brand called Pyrex was founded in 1915. Pyrex used a revolutionary type of glass called borosilicate glass, which was developed by the scientist Otto Schott from Germany.
He realized that the added boron oxide made the glass more robust and heat–resistant, so that it could withstand both high and low temperatures. These features made it an excellent option for manufacturing cooking products.
Anything bearing the Pyrex logo is safe to use in an oven, which helps to alleviate the concerns people have over cooking glass. It will not crack, even when exposed to very high temperatures.
Pyrex is still an extremely popular brand today, and it’s used in both domestic and industrial settings. There is a large range of Pyrex items available, from classic casserole dishes to lidded leftover pots – it is easy to find the perfect Pyrex product to suit your needs.
Many other brands produce oven-safe glass, so please don’t think that you can only buy Pyrex for all your cooking. However, it is definitely a good place to start if you’re new to purchasing kitchenware and want to make it as stress-free for yourself as possible.
While vintage Pyrex pieces can fetch hefty prices at auctions, a standard modern Pyrex dish represents good value for money and will last for a long time.
What Happens If You Put Unsuitable Glass In An Oven?
Glass is a delicate substance that is widely known for breaking easily. Everyone has had those unfortunate moments where a glass has slipped out of their hands when they’re trying to drink, and ended up making a huge mess on the floor.
Broken glass is especially awkward to clean up as well, because it’s clear and you can’t always spot all the shards – even the tiniest bit of glass can cut your skin if you accidentally step on it.
Some types of glass are thicker and more durable than others, and only these are used when manufacturing oven-safe glass products. The thinner, non-tempered ones are more prone to a phenomenon called thermal shock, which happens when glass is exposed to extreme temperatures and one part of the glass becomes hotter than the parts near it. The hot area experiences heightened stress, causing it to crack if the temperature difference is significant enough.
As mentioned above, dealing with shattered glass is an issue at the best of times. However, when you add food into the mix, the situation gets worse still. Even if it looks like your dish only has a crack in it but remains intact, it can fall apart entirely once you try to lift it out of the oven.
Then there is the risk of glass particles actually getting into your food, which can cut your mouth and damage your teeth if you eat it.
To put it simply: some glass is oven-safe, but some glass is not. Putting unsafe glass in the oven can introduce a whole host of issues, so you should make sure whatever glass you’re using will be able to withstand extended heat exposure before attempting to cook with it.
Where possible, only buy glass dishes where the packaging or material clearly states that they are oven-safe. These will have been tempered correctly so that they won’t succumb to thermal shock.
Knowing that your containers are oven-safe will give you peace of mind when cooking, allowing you to enjoy your favorite meals without problems.