What Is Reactive Glaze Cookware?

I love owning different dinnerware. The different colors and patterns bring cheer to the home decor and my dining table. 

Recently I came to know about glazed cookware sets that are called reactive glazed cookware.

I decided to find out more about them to add to my collection. 

What Is Reactive Glazed Cookware?

“Reactive” indicates that the glaze coating on top of the dinnerware has reacted in a ‘special way’. 

Dinnerware is often coated with a glaze coating to make it sturdy and non-porous.

In the case of reactive glazed cookware, the coating undergoes chemical changes during firing.

The most common phenomenon is oxidation or melting. As a result of this, particular variegation or pattern is created.

Reactive Glaze plate

What Is a Reactive Glaze? 

A basic glaze is made from four kinds of materials: lead, tin, salt, and feldspathic. There is also a new glaze that is similar to glass. Almost all glazes are transparent except tin. The tin glaze is white. 

The feldspathic glaze is usually used on hard porcelain while lead glaze is used on soft porcelain. 

Earthenware or stoneware is usually coated with lead glaze or white tin glaze. 

Salt glazes are also applied on stoneware and give a pitted appearance, just like an orange peel. The salt combines with the clay of earthenware underneath to form a sodium silicate glaze.

The term ‘biscuit’ refers to earthenware, stoneware, or porcelain that are unglazed

Also read: Hard Anodized Cookware – Pros and Cons

How Does a Reactive Glaze Cookware Appear?

A reactive glaze produces different mottled or variegated patterns. It will not have a solid color like a toilet sink.  

A reactive glaze is mostly applied on ceramic, porcelain, earthenware, or stoneware.

It contains a good amount of additions and fluxes to create one or more variegated patterns. The modern glazes contain finely ground glass powder that is mixed with water.

The textures and colors of dinnerware will be different according to the amount of change the reactive glaze undergoes being fired and fused with the clay underneath.

Tin glazes give an appearance of thick white paint on the dinnerware. 

Also read: Where Is Kutime Cookware Made?

What Are the Different Types of Glazes? 

There are six types of glazes: transparent, translucent, Matt finish, Opaque, Overglaze, and underglaze. 

Overglaze is achieved when you fire the cookware above the temperature that they require. Over firing your cookware leads to the formation of crystal shapes. 

Similarly, underglaze is when you fire the glaze at a lower temperature. This is mostly done for decorations and not for cookware. The underfired glaze is rougher and drier. This is because the correct temperature needed for the glaze to vitrify is not reached. 

There are also three types of glazes depending on the temperature you use. These are Low fire glazes, mid-fire glazes, and high fire glaze

The firing temperature of the glaze is matched with the firing temperature of the material underneath. 

High Fire Glaze

Most porcelain and stoneware clays use high fire glazes as they have a high firing temperature.

They produce dull, muted colors and make the cookware more durable.

The temperature that is usually used for high fire glazes ranges from 1249° C( 2280° F) to 1285° C (2345° F).

Low Fire Glaze 

Low fire glazes are used at temperatures between 998° C (1828° F) and 1063° C (1945° F). The result is a deep color with a gloss finish. 

Mid Fire Glaze 

Mid-fire glazes end up achieving earthy and bright colors.

The temperature ranges from 1186° C (2167° F) to 1239° C (2262° F). Most of the cookware sets are glazed at these temperatures. 

Also read: Where Is Made-in Cookware Made?

Is Reactive Glaze Cookware Safe to Use for Food? 

Most of the modern reactive glaze cookware is lead-free after the US food and drug administration limited the use of leachable lead for glazing cookware.

Lead is poisonous and slowly debilitates people with its poison. Lead was used earlier to glaze ceramic ware to produce an attractive shiny appearance. 

However, always double-check and look for a warning sign indicating it is not food safe or a sign indicating it is food safe.

You will find it stamped on the box, in the instruction booklet, or at the bottom of the cookware.

In case you find it, it means this is a decorative piece and not meant for serving or storing food. 

There are two tests with the help of which you can easily check if the reactive glaze is food safe. 

The Lemon Test 

Slice the lemon in half and squeeze out its juice on the horizontal glazed surface. You can also place the lemon peels over the freshly squeezed juice and leave it overnight. 

Next, remove the lemon, wipe away the juice and observe. If there is discoloration, the reactive glaze cookware is not food safe. 

I need to mention here that if there is no discoloration, it does not guarantee that leaching won’t happen.

It just indicates that the leaching is minuscule. 

The Microwave Test 

Fill your reactive glazed cookware with water and microwave it.

If the glazed layer is not vitrified, the clay underneath will absorb water and become very hot. This will cause the glaze to crack or chip.

Do not attempt this test on cookware having a metallic finish or trim as it might catch fire. 

Where Are the Glazes Fired?  

Glazes are fired up in kilns. As I have explained earlier, the heat in the kiln will change the appearance of the glaze due to a chemical reaction. 

The kiln can be electric or gas kilns. Gas kilns are not preferred and most of the glazing occurs in an electric kiln. This is because electric kilns produce more vibrant and bright colors.  

Electric kilns are also called neutral or oxidation kilns as they remove electrons. Gas kilns, on the other hand, add electrons.

Another reason why gas kilns are no longer popular is that they need oxygen to burn.  The glaze also melts faster in a gas kiln. 

How Are the Reactive Glazes Applied? 

There are many options with which glaze can be applied over cookware. You can brush, pour, spray and even dip.  

For brushing glazes, you need specialized brushes that will hold the glaze.

For optimum results, you need to brush three layers and let each layer dry up before coating with the second layer. 

Dipping is the most commonly used procedure to glaze the cookware.  While brushing may require many layers, all you need is one dip. Dipping glazes also dry up faster. 

Also read: Is Cookware Made in China Safe?

Which Is the Best Material for Dinnerware? 

Some of the best dinnerware sets are Porcelain, Bone china, and stoneware. Porcelain and Bone china are strong, non-porous dinnerware.

They are fired at high temperatures, making them oven-safe and microwave-safe. 

Bone china is famous for being a high-quality ceramic ware. Bone china is available as beautiful dinnerware pieces and is chip resistant. 

Stoneware is very durable. It is less porous and has a light color. Stoneware is also dishwasher and microwave safe. 

Some other good dinnerwares are Earthenware dinnerware and Melamine dinnerware.  For glasses, it is best to opt for plain clear glass. 

Also read: Is Nylon Safe for Cooking?

What Do You Mean by Glazed Plates? 

It simply means that the plate body is coated with a vitreous substance. When the plate is heated in the kiln, the glaze fuses with the ceramic or clay underneath.

It is a protective layer that forms to make the cookware nonporous. 

The glaze is usually applied on plates made from ceramic, stoneware, Porcelain, and Earthenware. 

The chemical changes make the glaze form different colors and patterns. This is why the plates appear pretty and bright. 

Are Old Glazed Dishes Safe to Eat From? 

I do not recommend you to eat from old glazed plates. Just like everything has a life duration, glazed lining also has a particular lifespan after which it starts to disintegrate.

It may crack, chip, shrink, or begin to Pitt. 

Once this happens, the lead will be easily leached out into your food.

Antique bowls and china used to be glazed with lead. Do not consume food from such antique chinaware. 

Which Glaze Materials are Not Food Safe? 

The glaze that uses lead or cadmium fluxes is not food safe. You may use them for decorative purposes.

Lead is usually added to brighten up and make the glaze flow better. Cadmium is used to produce red or bright orange Colors. 

Palladium glaze is not food safe. This is because highly acidic foods like tomatoes can cause the metals to leach from the glaze. 

Glazes contain additions and fluxes such as soda ash, alkaline feldspars, potassium carbonate, and fluorspar. These are skin irritants. 

Also read: What Is a Non Reactive Cooking Pan?

Are Unglazed Porcelain Plates Safe for Food? 

Yes, you can use Porcelain plates safely for serving and storing food. 

It is an inert material that can withstand heat, making it food safe with no chances of leaching. 


Cookware and dinnerware are glazed with a coating to give a particular color or texture. 

‘Reactive glaze’ simply means that the glaze has reacted to the temperature in the kiln.

The reaction is more of a chemical change that makes it able to form a particular color or pattern. 

Reactive glaze can be found on ceramic ware, stoneware, earthenware, and Porcelain. 

The glaze forms a glass-like transparent film over the clay to make it non-porous and sturdy.

There are six types of glazes in the market with the most commonly used reactive glaze being transparent. Matt finish, opaque, and underglaze are the next favorites for cookware.

Let me know which one you chose.

You can also glaze your cookware by watching the youtube link here. All the best!

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Hey there! I'm Sasha, just your regular mom-turned-kitchen-appliances enthusiast. When I gave my kitchen a makeover, I took a shine to new kitchen appliances like Induction Cooktops, Air Fryer, Instant Pot, Microwave, and Oven. I'm always up to some fun experiment, whipping up a storm, and writing about common questions people have about the efficient use of these kitchen gadgets