Controlling Temperature While Mixing Samples

Combining agitation at just the right temperature comes in handy in many lab processes. That’s when scientists turn to a temperature-controlled shaker. To get the best results, though, that device must shake and warm at the expected levels, and do so repeatedly.

When asked about the main use of temperature control in a shaker, David Hayes, global product manager at Cole-Parmer (Vernon Hills, IL), says: “Used in chemistry or biology, the temperature in an incubator shaker provides the optimal environment to promote cell culture procedures, such as yeast, bacteria, or tissue cultures.”

For cell culture work, the precision of temperature control can mean the difference between success and failure. When growing microorganisms, says Lee J. Lowenstein, president of Stellar Scientific (Baltimore, MD), “optimum growth conditions for these cultures include proper aeration and specific temperatures, and the shaker provides the aeration while the tight temperature control ensures the proper environment.” The best temperature can vary among cultures. As Lowenstein says, “Many cultures are grown at 37°C, however, other temperatures are often needed, especially for protein-expression studies.”

Here are some ways to pick the best shaker with temperature control for your lab:

Shake up the search

When looking for a shaker platform that provides temperature control, consider some important features. Be sure, Hayes points out, that a device will provide “temperature uniformity, temperature stability, and adjustable temperature.”

According to Lowenstein, “There are a number of temperature-related features that matter when deciding to purchase an incubated shaker.” At the top of Lowenstein’s list is “the ease of setting and control of temperature.” That control will be analog or digital. “Analog is less expensive, but digital is more precise,” Lowenstein says. “Digital temperature controllers require less routine maintenance, such as calibration.”

The required precision will depend on the application, and some depend on tight temperature tolerances. In those cases, Lowenstein says, “if you set the temperature for 36.5°C, you want to be sure that the incubator is reaching that temperature within a slight measure of variation.”

Uniformity also comes high on Lowenstein’s list. For this feature, he asks: “Is the temperature the same at every point within the chamber?” He adds, “If, for instance, the left-rear corner is slightly warmer than the right-front corner, in many studies that can cause a difference in the experimental outcome.”

Another question to keep in mind is: How fast will the temperature recover after opening and closing the door of an incubated shaker? “Quick recovery of the temperature environment is crucial—as is an alarm if the door is left open,” Lowenstein points out.

Some scientists will need even more control. As an example, Lowenstein says, “While not a necessary feature for many users, the ability to program changes in temperature over time may also be important.”

Stabilize your sample

A shaker needs some way to keep a sample in place. Most shakers, Lowenstein says, “use screw-in clamps to secure flasks and other vessels to the platform.” Alternatively, Lowenstein mentions that a “magnetic-clamp system keeps flasks rooted to the shaking platform.” This method keeps a flask or other container in place on a shaker, even at high rates of shaking, and it provides “convenient, quick ‘swapability’ to change from one size flask to another,” he explains.

So, from temperature stability to flask attachment, consider which shaker with temperature control will best meet your laboratory needs.

For additional resources on shakers, including useful articles and a list of manufacturers, visit www.labmanager.com/shakers