What Is a Bunsen Burner? Types, Uses and How to Choose

A Bunsen burner is a laboratory gas burner that produces a single adjustable flame for heating, sterilisation and combustion experiments. It mixes a fuel gas with air before ignition, allowing the user to adjust the flame from a visible yellow safety flame to a hotter blue heating flame.

Bunsen burners are widely used in chemistry, microbiology, education, materials testing and general laboratory work. Traditional models use manual gas and air controls, while modern safety burners can include automatic ignition, flame monitoring, timers and automatic gas shut-off.

Choosing the wrong burner can produce an unstable flame, incomplete combustion or an unsafe gas connection. The burner must match the available fuel, gas pressure, required flame size and intended application. This guide explains how Bunsen burners work, compares the main types and outlines how to select and use one safely.

Bunsen Burner Definition

A Bunsen burner is a gas-fuelled laboratory burner consisting of a stable base, gas inlet, gas jet, vertical barrel and adjustable air openings.

Fuel gas passes through a small jet at the base of the barrel. As the gas moves upwards, it draws air through openings in the burner before the mixture is ignited at the top. Adjusting the air supply changes the amount of oxygen mixed with the gas, which alters the flame's colour, temperature and combustion characteristics.

The familiar burner design is associated with German chemist Robert Bunsen and instrument maker Peter Desaga, who developed an improved laboratory gas burner during the 1850s. The same basic principle remains in use, although modern laboratory burners can provide substantially better ignition control and safety monitoring.

Parts of a Bunsen Burner

A traditional Bunsen burner normally includes the following components:

• Base: provides stability and helps prevent the burner from tipping.
• Gas inlet: connects the burner to an approved gas hose or supply line.
• Gas jet or nozzle: controls how gas enters the burner barrel.
• Barrel: the vertical tube in which gas and air mix before combustion.
• Air holes: allow air to enter the burner.
• Adjustable collar: opens or closes the air holes to regulate the flame.
• Gas-control valve: fitted to some models to regulate gas flow.
• Flame stabiliser: helps maintain a stable flame under changing conditions.

Not every Bunsen burner includes an integral gas valve. Some models rely on the laboratory bench tap for gas-flow control.

How Does a Bunsen Burner Work?

The burner operates by mixing gas with air before combustion.

When gas passes through the narrow jet, its velocity increases and pressure around the jet decreases. This draws surrounding air through the openings at the base of the burner. The gas and air mix inside the barrel before burning at the top.

The amount of air entering the burner determines the type of flame:

• With the air openings closed, the gas burns with limited oxygen and produces a visible yellow flame.
• With the openings partly open, more oxygen enters and the flame becomes blue, cleaner and hotter.
• With the openings opened further, the burner can produce a stronger blue flame with a distinct inner cone.

The exact flame temperature depends on the burner design, fuel gas, gas pressure, air setting and operating environment. Laboratory gas burners commonly operate at temperatures above 1,000 °C, while some safety burners specify maximum flame temperatures of approximately 1,200 °C.

Bunsen Burner Flame Types

Yellow Safety Flame

The yellow flame is produced when the air holes are closed or nearly closed. It is bright, easy to see and less intense than the blue heating flame.

The yellow colour is caused by glowing carbon particles formed during incomplete combustion. These particles can deposit soot on glassware and other surfaces.

The yellow flame is commonly used while the burner is temporarily not heating anything because it is easier to see. It should not be treated as harmless, and the burner must never be left unattended.

Blue Heating Flame

Opening the air holes allows more oxygen to mix with the gas. This produces a blue, non-luminous flame with more complete combustion.

The blue flame:

• Is hotter than the yellow flame
• Produces little or no soot when adjusted correctly
• Has a clearly defined inner cone
• Is used for most laboratory heating
• Can be difficult to see under bright lighting

A blue flame should be adjusted until it is stable and remains attached to the burner head.

Roaring Blue Flame

Opening the air supply further produces a strong blue flame that may make a noticeable roaring sound. This flame provides intense heating but requires careful adjustment.

Too much air or excessive gas flow can cause the flame to lift away from the barrel. An incorrect mixture can also cause flashback, where combustion moves into the burner tube.

If a flame flashes back, produces an unusual sound or burns inside the barrel, turn off the gas supply immediately. Allow the burner to cool before it is inspected or relit.

Where Is the Hottest Part of a Bunsen Flame?

An adjusted blue flame has several visible regions:

1. Inner dark region: contains unburnt gas and air.
2. Inner blue cone: combustion has started but may not be complete.
3. Outer flame: combustion is more complete because additional oxygen is available from the surrounding air.

The hottest area is generally in the outer flame just above the tip of the inner blue cone. Laboratory vessels should be positioned according to the required heating intensity and the laboratory's approved procedure.

Do not place glassware directly on the burner. Use a suitable tripod, ring stand, clamp, wire gauze or other heat-resistant support.

Types of Laboratory Burners

Standard Bunsen Burner

A standard Bunsen burner has an adjustable air collar but may not include a separate gas-control valve.

It is commonly used for:

• General laboratory heating
• Educational demonstrations
• Flame tests
• Heating test tubes and crucibles
• Basic microbiological work outside a biological safety cabinet

Standard Bunsen burners are simple and economical. The available flame control depends on the laboratory gas tap and the burner's air collar.

Tirrill Burner

A Tirrill burner provides separate adjustment of the gas flow and air supply. It normally includes a needle valve at the base, allowing finer flame control than a basic Bunsen burner.

Tirrill burners are useful when the operator needs:

• More precise flame-height adjustment
• Better control at low gas flow
• Repeatable heating conditions
• Separate regulation of gas and air

They are often used in chemistry teaching, analytical procedures and general laboratory heating.

Teclu Burner

A Teclu burner uses a conical mixing section and adjustable air inlet to provide efficient mixing of gas and air.

It can produce a strong, hot flame and is commonly selected for:

• Higher-temperature heating
• Glassworking
• Heating crucibles
• Applications requiring greater flame intensity

Its gas connection and nozzle must still match the laboratory fuel supply.

Meker-Fisher Burner

A Meker-Fisher burner has a wider barrel and a grid or mesh at the burner head. The grid divides the gas mixture into multiple small flames, producing a broad and relatively uniform heating area.

It is useful for:

• Heating larger vessels
• Heating crucibles
• High-temperature work
• Applications requiring a broader flame
• Reducing concentrated hot spots beneath a vessel

Meker burners generally consume more gas than standard Bunsen burners and require suitable bench space and support equipment.

Safety Bunsen Burner

A safety Bunsen burner is a modern laboratory gas burner with automatic ignition and integrated monitoring functions.

Depending on the model, features can include:

• Push-button ignition
• Infrared sensor activation
• Foot-pedal operation
• Timed flame programmes
• Flame monitoring
• Automatic gas shut-off
• Overheating protection
• Burner-head blockage detection
• Removable burner heads for cleaning

Safety burners reduce the need for matches, spark lighters or continuously burning pilot flames. They are useful in microbiology, pharmaceutical laboratories, clean work areas, education and laboratories where the flame is switched on and off repeatedly.

For example, the WLD-TEC Flame 100 Safety Bunsen provides automatic ignition, an adjustable precision flame and safety monitoring in a compact stainless steel design. See the full WLD-TEC range for related safety burners and accessories.

Micro Burner

A micro burner produces a smaller, more concentrated flame for low-volume or detailed work.

It may be appropriate for:

• Small samples
• Microbiology tools
• Fine glass tubing
• Dental tools
• Delicate or localised heating

Confirm that the burner provides sufficient heat output for the application. A compact burner is not automatically suitable for large vessels or prolonged heating.

Spirit or Alcohol Burner

A spirit burner uses liquid alcohol and a wick rather than a connected gas supply. It is not technically a Bunsen burner, but it is often considered for laboratories without fixed gas services.

Spirit burners are:

• Portable
• Simple to operate
• Independent of a gas outlet
• Suitable for basic, low-intensity heating

They provide less flame control and generally lower heating performance than a gas burner. The liquid fuel also creates filling, spill and storage hazards.

Bunsen Burner Types Compared

What Is a Bunsen Burner Used For?

Heating Laboratory Glassware

Bunsen burners can heat test tubes, beakers, flasks and evaporating dishes when the glassware is suitable for direct or indirect heating.

A support such as wire gauze helps distribute heat and reduces localised thermal stress. Never heat sealed glassware, damaged glass or a container not rated for the required temperature.

Precise or extended heating is usually better performed with a hotplate, heating mantle, water bath or dry block heater.

Heating Crucibles

A Bunsen, Teclu or Meker burner can heat crucibles during ignition, ashing and gravimetric procedures. The crucible should be supported by an appropriate clay triangle or other high-temperature support.

The burner must provide enough heat for the method without exposing nearby equipment or chemicals to the flame.

Flame Tests

Bunsen burners are used for qualitative flame tests in chemistry. Certain metal ions produce characteristic flame colours when introduced into a clean, non-luminous flame.

The blue flame is preferred because it provides a less visually interfering background than a yellow, soot-producing flame.

Bending Glass Tubing

Glass tubing can be softened and bent using controlled heating. A broader burner flame may help heat the circumference more evenly and reduce the risk of a sharp bend or collapsed tube.

Only glass types and diameters suitable for manual flame working should be used. Eye protection, heat-resistant tools and appropriate training are required.

Sterilising Inoculating Loops

A gas flame can heat a metal inoculating loop until it reaches the required condition for flame sterilisation. Modern safety burners provide on-demand ignition and hands-free control for this purpose.

Flaming can produce aerosols or spatter if contaminated material is heated too quickly. Follow the laboratory's validated microbiology procedure and use an appropriate enclosed electric or infrared steriliser where required.

Heating the Neck of Culture Vessels

Some microbiology procedures briefly pass the mouth of a culture tube or flask through a flame. This must be performed only where permitted by the laboratory's procedure.

A Bunsen burner does not create a reliably sterile area around the entire bench and should not be used as a substitute for validated aseptic technique.

Combustion and Educational Experiments

Bunsen burners are used to demonstrate:

• Combustion
• Complete and incomplete burning
• Convection
• Heat transfer
• Flame structure
• Emission colours
• Thermal decomposition

Students must receive instruction and supervision before using any open flame.

Can You Use a Bunsen Burner in a Biological Safety Cabinet?

Open flames are generally not recommended inside biological safety cabinets.

The heat produced by a burner can disrupt the cabinet's directional airflow. The flame may also damage filters, create turbulence and present a fire or gas-accumulation hazard.

Safer alternatives can include:

• Sterile disposable inoculating loops
• Electric loop sterilisers
• Infrared loop sterilisers
• Pre-sterilised instruments
• Validated chemical or steam sterilisation methods

Only use a flame inside a cabinet if the cabinet manufacturer, risk assessment and approved laboratory procedure specifically allow it.

Natural Gas vs LPG Bunsen Burners

Laboratory burners are commonly designed for one of the following fuel supplies:

• Natural gas
• Propane
• Butane
• Propane-butane mixtures
• Approved gas cartridges

Natural gas and LPG burners are not automatically interchangeable. These fuels have different pressures, energy contents and air requirements.

The burner jet or nozzle is sized for a particular gas and operating pressure. Connecting the wrong gas can result in:

• An unstable flame
• Incomplete combustion
• Excessive flame height
• Flame lift
• Flashback
• Soot formation
• Carbon monoxide production
• Equipment damage

A burner labelled for natural gas should not be connected to LPG unless the manufacturer provides an approved conversion procedure or replacement jet. Cylinder and cartridge installations also require the correct regulator, connector and gas hose. Do not create improvised adapters.

Does Burner-Tube Diameter Matter?

The internal diameter of the burner tube influences gas-air mixing, flame width and potential flow capacity. A larger bore may support a larger flame, but bore size alone does not determine heat output.

The final performance also depends on:

• Gas type
• Gas pressure
• Jet diameter
• Burner-head design
• Air opening
• Flame stabiliser
• Gas-control valve
• Burner height

When a procedure specifies a particular bore, such as approximately 10 mm or 3/8 inch, confirm the internal diameter with the manufacturer. Do not rely on the external barrel diameter or gas-inlet size.

How to Choose the Right Bunsen Burner

1. Confirm the Available Gas

Determine whether the laboratory has natural gas, LPG, a gas cylinder or an approved cartridge system.

Check the operating pressure and connection type. Select a burner supplied with the correct jet for that fuel.

2. Identify the Application

For routine test-tube heating, a standard Bunsen burner may be sufficient. More demanding applications can require a different design:

• Choose a Tirrill burner for finer gas adjustment.
• Choose a Teclu burner for an intense heating flame.
• Choose a Meker burner for broad, uniform heating.
• Choose a safety burner for automatic ignition and monitored operation.
• Choose a micro burner for small tools and localised work.

3. Consider the Required Flame Size

Compare the required flame height, flame diameter and heat output with the vessel or tool being heated.

A narrow flame is useful for precise work but may create hot spots on large glassware. A broad flame provides more even heating but can expose a wider area to heat.

4. Compare Safety Features

For frequent operation, teaching laboratories or microbiology, consider features such as:

• Automatic ignition
• Flame detection
• Automatic gas shut-off
• Operating timers
• Overheating protection
• Burner-head monitoring
• Foot-pedal control
• Touch-free infrared activation

These features do not remove the need for supervision, ventilation and correct gas installation.

5. Check the Burner Base

A broad, weighted or non-slip base improves stability. This is particularly important where flexible gas tubing could pull on the burner.

Some traditional burners are available with an optional safety base.

6. Check Cleaning Requirements

Microbiology and food laboratories may prefer stainless steel burners with removable heads and smooth housings.

Confirm that cleaning liquids will not enter the jet, electrodes or control system. The gas supply must be isolated before cleaning.

7. Select the Correct Accessories

The complete setup may require:

• Approved gas hose
• Correct regulator
• Bench-gas connector
• Gas cartridge adapter
• Spark igniter
• Foot pedal
• Tripod
• Retort stand
• Clamp or support ring
• Wire gauze
• Clay triangle
• Heat-resistant mat
• Wind or splash shield

Use only accessories approved for the burner and fuel system.

How to Use a Bunsen Burner Safely

Before lighting the burner:

1. Wear safety glasses and required protective clothing.
2. Tie back long hair and secure loose clothing.
3. Remove flammable liquids, paper and combustible materials.
4. Confirm that the burner matches the available gas.
5. Inspect the burner, gas hose and connections for damage.
6. Position the burner on a stable, heat-resistant surface.
7. Check that there are no shelves, lights or equipment directly above the flame.
8. Make sure the gas isolation point is accessible.
9. Close or reduce the air inlet before lighting, unless the manufacturer states otherwise.
10. Have the approved ignition device ready.

Light the burner according to the manufacturer instructions and local laboratory procedure. Adjust the air supply gradually until the required flame is stable.

During use:

• Never leave the flame unattended.
• Keep the gas hose away from the flame and hot equipment.
• Use tongs, clamps or heat-resistant gloves when required.
• Do not reach across the burner.
• Treat all heated glassware as hot, even when it looks cool.
• Do not move the burner while it is operating.
• Keep the flame away from solvent vapours and gas cylinders.

After use:

1. Shut off the gas at the bench tap or central supply.
2. Confirm that the flame is completely extinguished.
3. Allow the burner and supports to cool.
4. Disconnect portable supplies only as instructed.
5. Report damaged tubing, unstable flames or unusual odours.

Some burner designs cannot be fully shut off using the burner valve alone. For example, the manufacturer advises that certain Usbeck burners manufactured to DIN 30665 retain a small flame and must be isolated using the laboratory's central stopcock.

Common Bunsen Burner Mistakes

Most Common Mistake

Connecting a burner to the wrong gas supply. A natural-gas burner and an LPG burner may look identical, but their jets and pressure requirements can be different.

Other common mistakes include:

• Heating with a yellow flame: this provides less efficient heating and deposits soot on glassware.
• Opening the air supply too far: the flame may lift, become unstable or flash back into the barrel.
• Using damaged gas tubing: cracks, loose connections and unsuitable hose materials can allow gas to leak.
• Leaving the burner unattended: a flame can ignite nearby materials or be extinguished while gas continues to flow.
• Heating a sealed vessel: pressure can build until the container ruptures.
• Using an open flame near solvents: vapours can travel across the bench and ignite.
• Using a burner inside a biological safety cabinet: heat can disturb protective airflow and damage the cabinet.
• Looking down the burner barrel: delayed ignition or flashback can cause serious injury.
• Handling hot equipment too soon: the burner barrel, gauze, tripod and glassware can remain hot after the flame is extinguished.
• Closing only the burner valve: some models require the gas to be isolated at the bench or central stopcock.
• Using improvised adapters: incorrect fittings can leak or expose the burner to the wrong gas pressure.
• Assuming the blue flame is easy to see: it can be almost invisible in strong laboratory lighting.

Bunsen Burner Alternatives

Frequently Asked Questions

What is a Bunsen burner used for?

A Bunsen burner is used for heating laboratory vessels, performing flame tests, heating crucibles, bending glass tubing, sterilising suitable metal tools and demonstrating combustion principles. It provides an adjustable flame by mixing fuel gas with air before ignition.

How hot is a Bunsen burner?

The flame temperature depends on the burner, fuel and air setting. Many laboratory gas burners produce flame temperatures above 1,000 °C. Modern safety burners may specify maximum temperatures of approximately 1,200 °C, while some conventional burner and gas combinations can produce higher local flame temperatures. Always use the manufacturer's stated performance when a procedure requires a particular temperature.

Why is a Bunsen burner flame blue?

The flame becomes blue when sufficient air is mixed with the gas before combustion. The additional oxygen supports more complete burning, producing a hotter flame with little soot. A yellow flame indicates reduced air and incomplete combustion.

Which part of the Bunsen flame is hottest?

The hottest region is generally just above the tip of the inner blue cone within the outer flame. The exact temperature distribution varies with the burner, fuel, airflow and flame adjustment.

Can the same burner use natural gas and LPG?

Not unless the manufacturer specifically approves the burner for both fuels and supplies the correct jet, regulator or conversion components. Natural gas and LPG operate under different conditions. Using an incorrect burner or nozzle can produce an unstable and potentially dangerous flame.

What is the difference between a Bunsen and Tirrill burner?

A basic Bunsen burner primarily controls the air supply, with gas flow often regulated at the bench tap. A Tirrill burner provides separate gas and air adjustments, allowing finer control of flame height and intensity.

What is the difference between a Bunsen and Meker burner?

A Bunsen burner produces a relatively narrow single flame. A Meker burner uses a grid head to divide the mixture into many smaller flames, creating a broader and more uniform heating area.

Can a Bunsen burner be used inside a fume cupboard?

An open flame should only be used in a fume cupboard when permitted by the facility's risk assessment and operating procedure. Solvent vapours can ignite, and the flame may affect airflow or damage cupboard components. Never use a burner in a cupboard containing flammable vapours or combustible materials.

Can a Bunsen burner be used inside a biological safety cabinet?

Open flames are generally not recommended inside biological safety cabinets because heat can disrupt protective airflow and potentially damage filters. An infrared loop steriliser or sterile disposable loop is usually a safer alternative.

Why does a Bunsen burner make a popping sound?

A popping sound may indicate flashback, where the flame has moved into the burner barrel. This can occur because of an incorrect gas-air mixture, low gas flow, excessive air or a hot burner head. Turn off the gas immediately and allow the burner to cool before inspection.

How do I choose the correct burner-tube diameter?

Select the diameter according to the required flame size, gas flow and application. If the procedure specifies a bore such as 10 mm or 3/8 inch, confirm that the specification refers to the internal barrel diameter. Gas type, pressure, jet size and burner-head design remain just as important as the tube diameter.

Where can I buy a laboratory Bunsen burner?

LabFriend supplies traditional laboratory gas burners and modern safety burners for education, microbiology, research and industrial laboratories. Browse Bunsen burners at LabFriend or contact the LabFriend team with your gas type, required flame size and application.

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Need Help Selecting a Bunsen Burner?

The most important selection factors are the available fuel, gas pressure, required flame size, heating application and desired safety controls.

Whether you need a simple natural-gas burner for education, an LPG model for a cylinder supply or an automatic safety burner for frequent microbiology work, LabFriend can help you compare suitable options.

Browse the LabFriend Bunsen burner range or contact us with details of your gas supply and application.