For many applications, the exact nature of the stirring pattern is not important. Perfectly adequate mixing for many applications, particularly in preparative work, can be achieved by use of a magnetic stirrer. This type of stirrer rotates a magnetic stirrer bar placed in the solution by means of a rotating magnet. Many magnetic stirrers of this type also incorporate a hotplate which allows the solution to be heated at the same time as stirred. Magnetic stirrers tend to be well liked among researchers as they are simple to set up and use, involve no external moving parts, and can be used easily in a closed system, for example under a nitrogen atmosphere. However, this method of stirring is only suitable for relatively small volumes of a solution (up to around 4 L), and is generally not adequate when particularly viscous solvents need to be mixed.

For situations in which a greater volume or a higher viscosity solvent must be mixed, an overhead stirrer is often the preferred method. This consists of a motorized unit which is supported by a clamp and positioned above the solution to be mixed. A stirrer bar leads from the overhead unit down into the solution-containing vessel and rotates, mixing the solution. This type of arrangement requires a little more laboratory space than the simple magnetic stirrer, and can be more time consuming and awkward to set up. However, precisely the required stirring action can be determined with an overhead stirrer by choosing the most appropriate stirrer blade. For example, a radial flow pattern can be achieved by using a cross stirrer, a straight stirrer, or a centrifugal stirrer, while a tangential flow pattern can be achieved with a paddle stirrer. The former types of stirrer are suitable for low viscosity solutions requiring high speed stirring, while a paddle stirrer is suitable for low speed, high viscosity situations.

A third way to mix solutions in a laboratory is to use a laboratory shaker. This is particularly useful for mixing small volumes of liquid, and is commonly used to mix the contents of microplates, although it is also suitable for culture flasks, Petri dishes, and Erlenmeyer flasks. Laboratory shakers tend to agitate the solutions either in a linear reciprocal motion (backwards and forwards), or through an orbital motion which creates a vortex effect within the samples. The swirling action achieved with an orbital shaker tends to be suitable for gentle mixing or aeration, while the action of a linear shaker is more aggressive, making it ideal for applications in which reagents must be thoroughly mixed, such as extractions.

Laboratory mixers and stirrers have come a long way since the dawn of science when all solutions were stirred by hand. These days, it is not only possible for an automatic stirrer to mix a solution at a specified speed and for the required length of time, but now even the specific type of stirring motion can be predetermined. Who would have thought the simple act of mixing could cause such a stir?