What Glass is Safe For Candles?

  • By: Carl
  • Time to read: 9 min.

Candles add a touch of warmth and ambiance to any setting, but choosing the right holder for them is more than just a decorative decision—it’s a matter of safety too. The glass type used for your candles plays a critical role in this. From borosilicate to tempered, regular to recycled, each kind of glass offers unique properties and responds differently to heat. Let’s dive into this topic and identify what glass is safe for candles.

Borosilicate and tempered glass, known for their high heat resistance, are the safest choices for candles. Regular or soda-lime glass requires careful usage, while alternatives like ceramic or metal can also be safe. Choosing the right glass for candles is vital for safety.

Understanding the properties of different glass types helps ensure a safe and enjoyable candle experience. While borosilicate and tempered glass stand out for their heat-resistant qualities, regular glass, often used in common candle containers, demands a cautious approach. 

Exploring non-glass alternatives, such as ceramic or metal, can offer additional safety benefits. Remember, whichever material you choose, adhering to safe candle usage practices is paramount.

Understanding Different Glass Types

As you embark on your candle-making journey, you’ll come across several types of glass. Understanding these different kinds is crucial, as each has unique properties that affect its interaction with candle heat.

A Closer Look at Common Glass Types

Numerous glass types could potentially serve as your candle holder. Let’s explore these in more depth:

Borosilicate Glass

This high-heat-resistant glass is a frequent choice for laboratory equipment due to its ability to withstand temperature changes. Its resilience also makes it a favorite for certain luxury candles that require safe, heat-resistant containers.

Tempered Glass

This safety glass undergoes controlled thermal treatments to boost its strength significantly. The result is a durable material, often chosen for larger candle jars that need to endure heat over extended periods.

Regular Glass or Soda-Lime Glass

The most widely used glass type, soda-lime glass, finds its place in various everyday items, including several candle containers like mason jars, water glasses, and vases.

Recycled Glass

For the eco-conscious, recycled glass serves as an excellent candle container choice. It can, however, vary in thickness and durability, reflecting the original glass source and the recycling process it underwent.

Crystal Glass

If luxury and elegance are what you’re after, crystal glass is your go-to. Its high quality and aesthetic appeal make it the preferred choice for decorative candle holders and luxury scented candles.

Hand-blown Glass

The allure of hand-blown glass lies in its uniqueness – each piece is an original. It often houses artisan candles and specialty candle holders, offering a distinct, artistic appeal.

Heat Handling of Different Glass Types

It’s vital to grasp how each glass type interacts with heat, as this directly impacts your candle’s safety.

Borosilicate Glass

Known for its exceptional heat handling, borosilicate glass rarely cracks under intense temperatures. This makes it a reliable, safe choice for candle containers.

Tempered Glass

The thermal treatment that tempered glass undergoes enhances its heat resistance. This robust, enduring glass is an excellent choice for candles, especially larger ones that burn for longer periods.

Regular Glass or Soda-Lime Glass

Less heat-resistant than borosilicate or tempered glass, soda-lime glass requires careful monitoring when used with candles. Overheating can lead to potential cracking or breaking.

Recycled Glass

Given its varying thickness and original source, recycled glass’s heat resistance is inconsistent. It’s advisable to exercise caution when using recycled glass candle containers.

Crystal Glass

While crystal glass can handle candle heat, its primary function is often decorative. It’s best used with short-burning candles to avoid potential overheating.

Hand-blown Glass

Due to its unique crafting process, hand-blown glass thickness and shape can vary greatly. This also means that its heat resistance can fluctuate, and it’s always best to adhere to any safety guidelines provided.

Remember, irrespective of the glass type, never let a candle burn right down to the base. Extinguish it when only 1/2 inch of wax remains to avoid overheating the glass and compromising its integrity.

Borosilicate Glass and Candles

Borosilicate glass is a type of glass with a unique composition. It includes boron trioxide, which allows for a very low coefficient of thermal expansion. This means it’s less likely to crack under extreme temperature changes, unlike regular glass. 

Its high heat resistance and durability make borosilicate glass a preferred material in laboratories for test tubes, beakers, and other heat-sensitive applications.

Borosilicate glass’s high resistance to temperature changes makes it an excellent choice for candles. When you light a candle, the flame’s heat can cause the glass to expand. When extinguished, the glass contracts as it cools. 

This continual expansion and contraction can lead to stress fractures in regular glass. However, borosilicate glass’s low thermal expansion means it handles this process better, reducing the risk of cracking or breaking. This ensures a safer candle burning experience.

Tempered Glass and Candles

Tempered glass is four times stronger than regular glass, thanks to a process called tempering. This involves heating the glass to over 600 degrees Celsius, then cooling it rapidly. This process increases the glass’s strength, making it more resistant to breakage from impact or temperature changes. 

If tempered glass does break, it crumbles into small granular chunks instead of shattering into jagged shards, reducing potential injury.

Tempered glass’s enhanced strength and heat resistance make it a safer choice for candle containers, especially larger ones. The tempering process it undergoes allows it to handle the heat produced by a candle flame much better than regular glass. 

Even in the rare event of breakage, the small, less sharp pieces it forms reduce the risk of injury. Its durability and safety features make tempered glass a popular choice for larger, long-burning candles.

Regular Glass and Candles

Regular glass, also known as soda-lime glass, is the most common type of glass. It consists of about 70% silica (silicon dioxide), 15% soda (sodium oxide), and 9% lime (calcium oxide), with the rest made up of various other elements. 

While it’s used in a variety of applications, from windows to glassware, it has a higher coefficient of thermal expansion compared to borosilicate or tempered glass. This means it expands and contracts more with temperature changes.

Although regular glass is widely used for candle containers due to its versatility and affordability, it may not always be the safest choice. Its higher thermal expansion means it’s more prone to cracking or shattering due to the heat of a candle flame. 

If a candle burns too low, the heat may cause the glass to crack, potentially leading to a safety hazard. Therefore, when using regular glass candle containers, it’s crucial to monitor the candle closely, especially as it burns down to the end.

Alternatives to Glass for Candle Holders

Exploring Non-Glass Alternatives for Candle Holders

While glass is a common choice for candle holders, other materials are also used. These include ceramic, metal, and stone.

Ceramic holders are widely used due to their heat resistance and variety of designs. They’re often thick and sturdy, making them a safe choice for larger candles.

Metal holders, like those made from iron or brass, are also a popular choice. Their high melting point makes them safe for candles, and they can add a rustic or vintage touch to any decor.

Stone holders, such as those made from marble or granite, offer a natural and elegant aesthetic. Their high heat resistance and stability make them an excellent choice for larger or heavier candles.

Safety Comparisons Between Glass and Alternative Materials

Each material comes with its own safety considerations. Ceramic, metal, and stone all have higher heat resistance compared to regular glass, making them safer in terms of temperature changes.

However, other factors also come into play. For example, metal holders can become hot to the touch, posing a burn risk if handled carelessly during or shortly after burning a candle. Ceramic holders can crack if dropped, while stone holders, due to their weight, could pose a risk if knocked over.

Always consider the specific safety features and potential risks of any candle holder material, whether it’s glass or an alternative.

Understanding Candle Containers

Candle containers come in various shapes, sizes, and materials. Some are designed to fully contain the candle, like jar or tin candles. Others, like pillar or taper holders, are designed to hold the candle in place while it burns.

The container’s material affects how it handles heat. As we’ve discussed, materials like borosilicate glass, tempered glass, ceramic, metal, and stone handle heat well, making them safer options.

The design of a candle container plays a significant role in candle safety. A well-designed container should be stable to prevent tipping, and it should be large enough to contain the candle flame and any melting wax.

Open containers, like pillar or taper holders, require extra care as the open flame can easily come into contact with flammable objects. Fully enclosed containers, like jar or tin candles, help contain the flame, but they also need proper ventilation to prevent overheating.

Safety Tips for Using Candles

Quick Tips on Safe Candle Usage

Always follow these basic safety tips when using candles:

  1. Never leave a burning candle unattended.
  2. Keep candles out of reach of children and pets.
  3. Ensure candles are on a stable, heat-resistant surface.
  4. Keep candles away from flammable items.
  5. Trim the wick to 1/4 inch before each use.
  6. Extinguish a candle if it smokes, flickers, or the flame becomes too high.

How to Avoid Common Candle Safety Issues

Avoiding common safety issues is as simple as practicing mindful candle use.

Ensure your candle is in a well-ventilated area away from drafts, which can cause uneven burning or rapid flame movement. Always burn candles in containers designed for candle use.

When burning a candle, monitor it closely, especially when it’s nearing the end of its life. Always extinguish a candle when it burns down to 1/2 inch to avoid overheating the container.

Following these tips can help you enjoy your candles safely.

Frequently Asked Questions

Why is borosilicate glass a good choice for candles?

Borosilicate glass is a safe choice for candles because of its high heat resistance. It’s less likely to crack or break when exposed to the heat of a burning candle, reducing the risk of accidents.

Why is tempered glass used for candles?

Tempered glass is used for candles because it can withstand higher temperatures without breaking or cracking. It’s especially suitable for larger candles that burn for extended periods.

What are some alternatives to glass for candle holders?

Some alternatives to glass for candle holders include ceramic, metal, and stone. Each material has its own properties and considerations when it comes to heat resistance and safety.

How does the design of a candle container affect its safety?

The design of a candle container plays a significant role in its safety. A stable, well-designed container can prevent tipping, while a container large enough to contain the flame and any melting wax can prevent spills or accidental fires.

What is the best material for candle containers?

The best material for a candle container depends on the specific needs of the candle and the user. Borosilicate and tempered glass are excellent choices for heat resistance and safety, while materials like ceramic, metal, and stone offer unique aesthetics and other benefits.

Why is it crucial to monitor candles in regular or soda-lime glass containers?

It’s crucial to monitor candles in regular or soda-lime glass containers because this type of glass is less heat-resistant. If the glass gets too hot, it could crack or break, potentially causing accidents.


In conclusion, when it comes to choosing a safe glass for candles, it all boils down to understanding the different types of glass and how they handle heat. Borosilicate and tempered glass are exceptional choices due to their high heat resistance and durability, reducing the risk of cracking or breaking. 

On the other hand, regular or soda-lime glass, while common and versatile, requires more cautious use. Recycled glass, crystal glass, and hand-blown glass also have unique characteristics and considerations.

Remember, alternative materials like ceramic, metal, or stone can also serve as candle holders. The key is to choose a material and design that provide stability, heat resistance, and safety.

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