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What are conical flasks?

Known under a variety of names, including the titration and the Erlenmeyer flask, this laboratory flask looks quite similar to an upside-down funnel, with a flat, round base and conical body, which slopes towards a cylindrical neck. Typically made of glass and supplied with a bung, they often feature units of measurement on the side.

Why conical flasks?

Conical flasks are one of the larger containers used in a laboratory environment and are often used to mix or boil larger amounts of chemicals. Their design means that swirling a liquid inside to agitate or mix won't lead to a spill which maintains the controlled principles of a laboratory setting.

When are conical flasks used?

Used widely in laboratory settings, conical flasks are also used in schools for chemistry lessons and even in bars for cocktail displays. Typically, they're used to measure chemicals or store gases, but they can also be used for boiling and mixing chemicals too.

Conical flask types

There are two types of conical flasks available in a variety of sizes. Mostly made in clear glass, some versions are made in an amber colour to protect light-sensitive chemicals.

Narrow neck conical flask   -   The narrow neck on this type of conical flask is ideal for holding a funnel to filter sediment and other contaminants away from a liquid.

Wide neck conical flask   -   The wider neck design of these laboratory flasks allow for denser liquids to be combined by stirring with a rod.

Considerations when choosing conical flasks

Size - often a range of sizes are required to cover all requirements, with each type of flask classified by their capacity in millilitres.

Colour - available in a choice of clear or amber, the most popular of these is clear, although amber colour is ideal for light sensitive substances.

Neck type - depending on the experiment and the solution, the neck width of a flask will dictate whether you can use a rod to stir or not.

Conical flask jargon buster

There are a couple of international standards relating to conical flasks, so we've chosen one to break down and explain to keep you informed and up to date with quality requirements for laboratory equipment.

What does standard BS EN ISO 4797:2015 mean?

This quality standard outlines the requirements for the manufacture of boiling flasks with conical ground joints for laboratory use.

Let's break it down...

• BS - Short for the British Standards Institute, this standard is part of British legislation.

• EN - These initials mean European Norm, which is derived from the German translation, and highlights that this standard has been adopted in Europe.

• ISO - This stands for the International Organization for Standardization which is the independent governing body for all international standards.

• 4797 - This is the legislation number for this standard.

• 2015 - This standard was published in 2015 and supersedes the 2004 version. International standards are reviewed every five years, with this standard reviewed and confirmed in 2020.


Why not use a test tube instead of a conical flask?

Test tubes have their place in the laboratory and are very useful. However, when a chemical reaction is expected to be larger than the capacity of a test tube, or two chemicals need to be mixed thoroughly, a conical flask is the ideal piece of equipment for the job.

How do you wash a conical flask?

Due to the nature of the chemicals used in a conical flask, it's important to rinse the flask using distilled water only to ensure all residual chemicals are washed away.