What is the difference? 

Both water and bead baths are used to warm laboratory reagents, such as media, as well as incubate samples. As the names imply, a water bath is full of water, and a bead bath is filled with thermal metal beads.

Key Differences

• Water conducts heat evenly, whereas bead baths can cause uneven temperature distribution. When using a bead bath, it is a good idea to use a temperature probe to check for the temperature near your sample or reagent.
• Water baths are prone to contamination, whereas bead baths, such as those filled with aluminum Lab Armor® thermal beads, are resistant to contamination. This is especially important for applications where samples or reagents must stay sterile, such as cell or tissue culture media. 
• Water must continually be added to a water bath or turned off to ensure it doesn’t dry out, posing a fire hazard. Bead baths, on the other hand, can remain on and be ready for use at any time.  
• Water baths often include lids to combat evaporation, while bead baths are usually open.
• Bead baths are easier to maintain, requiring much less cleaning. 

PolyScience Digital 28 Liter Water Bath            Lab Armor Digital Bead Bath

Is a bead bath just a water bath filled with beads? 

No, but many laboratories will simply swap out water for Lab Armor® beads and repurpose the water bath. Before you do this, there are some things to be aware of.  Water baths tend to have a single heating element. Because water conducts heat very well, this is perfectly suitable for a water bath without sacrificing temperature distribution. However, a single heating element will not evenly heat beads since they are not as good at conducting heat. There are usually multiple heating elements in a dedicated bead bath that surround the chamber to provide more even heat distribution. 

Selecting a Bath

When selecting a warming bath, consider how it will be used and who is using it. Some questions to consider include: 

• How concerned are you with contamination for your applications? If highly, opt for a bead bath or a combination option. For cell and tissue culture applications, a bead bath is almost always going to be the better option. 
• What items will you be warming and how sensitive are they to temperature fluctuation? If temperature fluctuations will be particularly problematic, you may want to stick with a water bath. Also, consider the size and shape of these items. Beads can accommodate any vessel, including cell culture plates or odd-size containers, whereas water baths will require appropriate racks, floats, or other supports.
• Who will manage the cleaning and maintenance of the bath? If you do not have someone willing or able to ensure the water bath is clean and does not run dry, a bead bath may be the safer option.  
• For your purposes, does the bath need to be ready to go at any time or will there be time to warm a water bath? If you will be using it multiple times per day and with little notice, a bead bath is the better option.