Three Types Of Glassware That Can Be Heated

There are many concerns about cookware; for example, some may want to know if a plastic container is microwave-safe or what glassware can be heated.

If you are a pro or a veteran at cooking, common sense tells us that heat can bring forth a lot of chemical changes and reactions, and the same can be said to our cooking utensils as well. This article discusses a few types of glassware that can be heated and those that cannot be.

When it comes to glassware for cooking (and even in laboratories), Pyrex glassware is always a reliable choice. Other glassware, such as a select few glass cups and glass plates, are heatable as well. Of course, research is still essential before one heats their glassware.

When it comes to kitchen knowledge, all you need to do is leave everything up to us! Let us understand and explore what glassware can be heated. 

Can Glassware Be Heated?

Glass is far from the most durable thing in the world, and in fact, it is pretty brittle as a slight shock, either from falling and, yes, to a sudden change in temperature, can compromise its integrity heavily.

However, despite being brittle, it is still entrusted with containing liquids, solids, and gasses, with components from food to heavily corrosive laboratory chemicals. With its extensive uses yet pretty questionable integrity, can glassware be heated, and what glassware can be heated?

The answer is not very simple, as it may seem, unfortunately. Glassware is created through extreme heat and molded through high temperatures, yet not all can withstand heating. Particular kinds of glassware are pretty reliable when heated, even allowing you to cook with said glassware.

However, some glassware, and yes, even glassware such as cups (as you would expect to at least stand boiling water), breaks with minimal effort. The critical point in this argument is that glassware that is graded and approved for use in heating, such as cooking, and most especially lab-grade glassware, is pretty reliable when it comes to heat.

However, when talking about non-graded glassware, we may not very well establish its reliability. It is critical to avoid using heating elements, nor will it be wise to use heated chemicals and materials such as hot water.

To understand this concept better, we must first ask why some glassware breaks when heated and why some put up with high amounts of heat? Without further ado, let us get started.

Why Does Glass Break When Heated?

Thermal shock, or thermal fracturing, is a phenomenon that happens to many materials, but in this context, to glass. It often manifests first when an audible popping sound erupts, and a streak of fractured glass appears.

It can happen to glass cups, glass cookware, and even glass plates, more commonly on glassware not to be used with heat, and on occasion, on heat-resistant glassware.

Thermal shock in glassware occurs when there is a temperature difference between the two surfaces of the glass. Because glass expands under heat, the heated side will expand swiftly while the more relaxed side will fail to respond accordingly, resulting in stress. When stress builds up, it will manifest itself as a crack on your glassware.

Because thermal shock happens when there is a temperature difference, not only situations such as sudden heating can break the glass. Sudden cooling can induce thermal shock, so heating or freezing glass is NOT a good idea whatsoever.

The type of glass that is very prone to breaking is called float glass which you can find on many window panes. However, most glassware used a kind of reinforced glass or any strengthening method of some sort. At this point of the article, we will discuss what glassware can be heated and what types you should use.

Glassware That Can Be Heated? What Glassware Can You Heat?

Now that we have discussed why glass breaks when heated or what thermal shock is, we will proceed with the bread and butter of our article: determining what types of glassware can be heated.

Of course, all the glassware mentioned here is suitable for heating given that they are graded and approved for cooking or heating purposes.

Below Are Three Types Of Glassware That Can Be Heated:

  1. Cooking-grade glassware
  2. Glass plates
  3. Pyrex glassware 

Cooking-Grade Glassware

Cooking glassware is a remarkable invention that allows people, especially those fond of the kitchen and the very act of cooking, like you and me, to do said tasks in a more exquisite and fancier manner.

Most people like to make use of glass cookware due to its ability to be transparent. Unlike most metal or clay cookware, glass is transparent, allowing people to see the ingredients get cooked inside without physically lifting the lid.

Another thing most people like about glass cookware is that they are very suitable for use in ovens, as glass cookware does not react with particularly acidic foods, especially those with vinegar added.

Moreover, no studies have shown that glass releases toxic chemicals or has adverse effects on the human body. These non-reactive properties allow the glass to be a top-notch material for cookware, health, and safety-wise.

However, glass also comes with its caveats, primarily when used as a cookware material. Although extremely attractive for aesthetics, glass, as discussed earlier, is not a very durable material.

Although said glass may be rated safe for cooking, it can still break due to thermal shock, and simple missteps, such as drops, may result in breakage, unlike steel cooking pots which can easily withstand drops of a few meters high.

Moreover, glass cookware needs to be handled with extreme care, needing to use self-polishing, non-abrasive cleaners for cleaning. Unlike most cookware that can withstand “ungga bungga” cleaning tactics, glass cookware requires extreme care and patience in handling and a meticulous mindset for execution.

Although glass cookware is very effective on ovens due to its ability to conduct heat, it simply falls off when one wants to do stovetop cooking.

The simple fact is that glass cookware, although conductive, does not spread out heat evenly, making some areas cooler and some warmer than others, resulting in unevenly cooked dishes. However, most will not notice these regional temperature shifts and differences. 

So what types of glassware can be heated? Glass cookware can be heated but needs careful handling and careful use, especially when it comes to stovetop cooking.

Glass Plates

Glass plates may not be your number one choice for heatable glassware, but it turns out that you can heat glass plates, albeit with its limitations. Since glass plates are not suitable for heating, I highly recommend you not to warm them up. However, if you really must, there are a few thresholds you may need to know.

First off, only tempered glass plates can hold heat, so if your glass plate is not under the tempered classification, or you are simply unsure, please refrain from heating them. Moreover, they have a threshold of around 400 degrees Fahrenheit.

Pyrex Glassware

Pyrex glassware is very famous for its usage in cooking as well as in labs. Such popularity is because of pyrex glassware (not plasticware) manifested with heat resistance in mind.

They do this by reinforcing the glass and by using borosilicate glass instead of regular tempered glass. So if you happen to have pyrex glassware, always remember that it is oven and microwave-safe!

Frequently Asked Questions

1. What Makes Some Glassware Heatable? The Importance Of Borosilicate Glass.

At this point, we all now know that some types of glass are suitable for heating and some are not. For example, while many glasswares suck at heating, some glassware manufacturers, such as Pyrex, excel in heat-resistant glassware. How do they make these glasswares possible?

The answer? Borosilicate glass.

Borosilicate glass single-handedly made heatable glassware possible due to its ability to limit glass expansion due to heat. As we all know, thermal shock in glassware occurs when the two glass surfaces have a significant temperature difference. While the hotter surface expands, the cooler surface does not, mounting up pressure that manifests itself as a crack. 

Borosilicate glass aids this pressure by having an excellent property: limited thermal expansion. Because borosilicate glass does not expand at the same rate as standard float glass, it does not exert much pressure even when under heat, preventing thermal shock.

Companies like Pyrex make use of borosilicate glass in their products. This usage makes Pyrex an industry leader in heat-resistant glass.

2. Can I Use Glass Plates In A Microwave?

Yes, you can. As long as your glass plates do not have gold or silver engravings, they should be acceptable for use. But always check the bottom for an embossed stamp in the glass that says it’s safe, otherwise it may not be safe for your microwave. 

3. Can I Use Glass Cups In An Oven?

Unless indicated, glass cups are not safe for oven use. Any glassware should have an embossed stamp on it that says what it is safe for use for; if it doesn’t assume it’s not safe for the oven.

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