Heating magnetic stirrer 12 L

Quick Answer: Heating magnetic stirrer 12 L is a hotplate stirrer that heats and mixes volumes of liquid up to twelve litres in one vessel. It is suited to prep-room batches, such as warming class stock solutions or dissolving agar for a full set of plates.

Heating Large Batches in One Vessel

Making up a solution for a whole year group, or enough agar for several classes, usually means working in a 2 to 5 L flask or beaker rather than many small ones. Hand-stirring such volumes while they heat is slow and uneven: the liquid at the bottom overheats while the top stays cool. A heating magnetic stirrer 12 L keeps the whole batch moving so that heat spreads through it and solids dissolve evenly.

Large volumes change the practical details. Heating takes much longer than for a beaker on the bench, so start early rather than turning the plate up to hurry it. A long stir bar, often 50 mm or more, is needed to move the liquid in a wide vessel, and it must be centred over the drive before the speed goes up. The 12 L rating applies to water; thick media need a smaller batch.

Weight matters too: several litres of liquid plus glassware is heavy, and a full vessel is awkward to lift off a hot plate. Decide where it will go before heating starts, and keep heat-resistant gloves at hand.

Specifications

Prep-Room Jobs for a 12 L Stirrer

• Dissolving and heating agar-based media in bulk before autoclaving
• Preparing class stock solutions in a single large batch
• Dissolving slow-to-dissolve solids, such as gelatin, in large volumes
• Warming several litres of water for a class set of heat-transfer practicals

Working Safely with Large Volumes

• Leave headspace: a vessel filled to no more than about two-thirds allows for foaming and for the vortex.
• Watch agar and gelatin closely as they near boiling, because they foam suddenly and can boil over.
• Check that the vessel base is flat and fully in contact with the plate before the heater is switched on.
• Keep the bench clear around the stirrer so a hot, heavy vessel can be moved without obstruction.

Why Choose LabEquip

This size is chosen by prep rooms and college technicians who make solutions for many benches at once. LabEquip lists it with smaller models in its General Lab Products range, and the larger heating magnetic stirrer 16 L is an option where batches are bigger still. Send your batch sizes through the contact page.

Frequently Asked Questions

Does 12 L mean I should always fill a 12 L vessel?

No. It is the largest volume the stirrer is rated to mix, measured on water. Most batches are smaller, and thick liquids should stay well below the limit.

How long does it take to heat a large batch?

Much longer than a small beaker, and the time grows with the volume and the wall thickness of the vessel. Start early, and cover the vessel loosely to cut heat loss from the surface.

What length of stir bar is needed for 5 L?

Choose a bar a little shorter than the vessel base diameter, typically 50 to 80 mm for a 5 L flask or beaker. A short bar leaves the outer liquid still and gives uneven heating.

Can agar be dissolved on the stirrer?

Yes. Stir the agar into cold water, then heat while stirring until the solution clears, watching closely near the boil because agar foams quickly. Sterilise the medium afterwards in an autoclave.

Is a borosilicate bottle safe on the heated plate?

Borosilicate media bottles and flasks tolerate hotplate heating, but loosen the cap so pressure cannot build up, and do not put cold glass onto a plate that is already hot.

What should I do after heating a large batch?

Switch off the heater first and let the stirring continue while the liquid cools, which avoids a hot layer at the bottom. Treat the plate as hot until it has cooled down.

Last Updated: September 2026