Condenser, Liebig (Sampling)

Quick Answer: A Liebig condenser is a water-cooled glass condenser with a straight inner tube running through an outer jacket. It is the standard condenser for simple distillation, sloping down from a still head so that condensed liquid flows into a receiver.

Straight-Tube Cooling for Distillation

The Liebig condenser is the plainest water-cooled design. Vapour passes down a straight inner tube while cold water flows through the jacket around it, entering at the lower connection and leaving at the upper one so that it runs against the vapour. Because the inner tube is straight, condensed liquid drains freely at any angle, which is why this design is the usual choice when a distillate has to be collected rather than returned to the flask.

It sits at the heart of most school and college laboratory distillation apparatus: a flask, a still head with a thermometer at the level of the side-arm, the condenser, an adapter and a receiver. It also works for reflux with gentle boiling, although a bulb or coil condenser gives more cooling for the same length. The straight tube is the easiest condenser to clean and inspect.

The word Sampling in the listing title is not explained, and the listing gives no jacket length or joint details. Buyers should confirm what the term refers to, together with the dimensions and end fittings, when ordering.

Applications

• Simple distillation of water from salt solution, or of ethanol from a fermented mixture
• Solvent recovery after extractions
• Steam distillation of essential oils from plant material, paired with a steam generator
• Reflux of mixtures that boil gently, where a straight tube gives enough cooling

Specifications

Care & Handling

• Clamp the condenser at its middle, not by the side-arms, and support the receiver end.
• Start the cooling water before heating, and check that the outflow runs cool throughout the distillation.
• Drain the jacket before storage so hard-water scale does not build up and cloud the inner tube.
• Push a long brush right through the straight tube to clean it, then rinse with distilled water.

Why Choose LabEquip

Chemistry teachers and college lab managers usually order Liebig condensers with the flasks, adapters and receivers of a full distillation set. LabEquip supplies them through its chemistry lab equipment range, along with flasks such as the short neck boiling flask with interchangeable joint; send your requirements through the contact page.

Frequently Asked Questions

Why is the Liebig condenser used for distillation rather than reflux?

Its straight inner tube lets condensed liquid drain freely when the condenser slopes down to a receiver. It can reflux too, but bulb and coil condensers provide more cooling surface for the same length when vapour has to be returned to the flask.

Where should the thermometer bulb be during distillation?

In the still head, level with the side-arm that leads to the condenser. There it measures the temperature of the vapour entering the condenser, which is the boiling point of the fraction being collected.

Does it matter which end the water goes in?

Yes. Water should enter at the lower connection, nearest the receiver, and leave at the upper one. This keeps the jacket full and brings the coldest water to meet the vapour just before it leaves the condenser.

Is this condenser suitable for steam distillation?

Yes. Steam and the volatile oil pass together through the condenser, and the condensate separates into oil and water layers in the receiver. A strong flow of cold water helps, because steam carries a lot of heat.

How can I stop hot liquid bumping into the condenser?

Add anti-bumping granules to the flask before heating, never to a hot liquid, and do not fill the flask more than about half full. Heat steadily so the liquid boils smoothly.

How long should the condenser be?

A longer jacket gives more cooling and suits volatile liquids or faster distillation, while a short condenser is adequate for water and higher-boiling liquids heated gently. Choose a length that also fits your stands and bench space.

Last Updated: September 2026