Mixing solutions is one of the most common laboratory tasks.

Magnetic stirrers are a popular type of laboratory stirrer that use a rotating magnetic field to cause a stirrer bar to rotate within the solution. These stirrers are often combined with a hotplate and are ideal for small volumes of non-viscous liquids and for situations in which a reaction must take place in a closed vessel or system. The overhead stirrer, however, is more suitable for larger volumes and more viscous solutions, but can be less convenient and more time-consuming to set up.

Lab shakers are available in two different mixing actions: orbital and reciprocal and are primarily used for culturing organisms in shake flasks or test tubes, and can also be used for mixing liquids. Shakers range from small to mid-size bench top models, larger-capacity console (floor standing) models, or spacesaving stackable models. Heavier loads may also require a heavy-duty drive mechanism such as a triple-eccentric drive vs. a lighter-duty single-eccentric drive. Samples in a lab shaker can be agitated via a linear motion or by an orbital motion to create a vortex in the solution. The principal application of shakers is for growing yeast, bacteria, or mammalian cells in specialized containers known as shaker bottles.

Different types of lab shakers and stirrers respondents are using or planning to purchase for their labs:

Components respondents are using or planning to purchase with their lab shaker and stirrers:

There are many different factors to consider when making a lab shaker or stirrer purchase: is the equipment going to be used to grow cultures or to mix chemicals and liquids? Is temperature control needed and, if so, do you need incubation only or refrigeration as well? Do you need digital controls to ensure precise and reproducible results, or will analog controls do?

The technology in lab shakers and stirrers continues to advance at a fast rate. The future for lab shakers and stirrers is likely to involve the development of instruments that offer alternative mixing actions for more thorough and efficient mixing, possibly mimicking further the action of the human wrist. Other innovations are likely to include instruments capable of mixing more samples simultaneously and greater integration with other lab processes, allowing for more automation in the laboratory and less human intervention. A number of automated methods for mixing have been devised, all of which remove this burden from the operator by offering a sustained and controlled stirring action for indefinite periods of time.

Choosing a shaker comes down to such features as heating/cooling capability, capacity, shaking speed, orbital vs. reciprocating motion, ease of use, programmability, heating capability, and footprint. With research budgets tight and lab space even tighter, groups or departments are increasingly sharing shakers. Fourteen percent of respondents choose models that they are able to stack and keep them in a shared equipment room.

Customers also value ease of use—the ability to utilize shakers fully, out of the box, with labware of any shape and size.

The choice of overhead or magnetic stirring to achieve uniform mixing is relatively straightforward, based on scale and viscosity of the medium being stirred. Overhead stirrers are used when sample viscosity and/or size are issues, or when there exists a concern for significant changes in viscosity.

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