How can I optimise my magnetic stirring? To ensure the best possible stirring, we advise: Use the stirring bar we recommend for the piece of equipment / glassware you are using. You could alternatively test a range of stirring bars – we offer three stirring bar evaluation kits, each containing a selection of stirring bars of different sizes and shapes. Standard stirring bars lose their magnetism with time and use, so try replacing old stirring bars. Rare earth stirring bars contain stronger magnets than standard stirring bars, so are particularly useful for stirring relatively viscous samples. If your sample is very viscous, it may be that magnetic stirring is not sufficient and you require overhead (mechanical) stirring instead. Depending on your sample size and number, the Tornado module for the Carousel 6 may be appropriate for you, or you could use a single overhead stirrer motor with a stirring guide for a single flask in Heat-On or Cool-It. For further details, please view the other FAQ entries on this topic – type ‘stirring bar’ in the search box.