DIY stir plate

My friend Jon says that the essence of hardcore punk is 'DIY'. I love that as a definition of punk and I like the idea of being a bit handy but I don't have a great DIY track record myself. This is my attempt to build a stir plate, something that will help my yeast starters to grow big and healthy.

It took:

• A PC fan
• A 12v adaptor
• A couple of crazy rare earth magnets
• A LED dimmer (for speed control)
• A plastic container
• Bolts, nuts, washers, blu-tac

I drilled holes in the lid to mount the fan. 4 bolts, each with 3 nuts between the lid and fan to provide a bit of space for the magnets to sit on top of the fan. A couple more holes in the container, one on the end for the speed controller and one on the side for the power chord.

Magnets nicely balanced and spaced for my stir bar

After stripping the wires for the power supply and the fan, they were hooked up to the speed controller.

I attached the magnets to the top of the fan as in the picture. I'd read that some people had difficulty getting them balanced and others had difficulty with spacing the magnets. I wasn't confident to just glue them down and blu-tac made it easy to get it right. It also means that I can easily move the magnets if I get a longer stir bar.

DIY stir plate in action

Pretty simple and totally effective. The bar spins well and stays spinning properly even at full speed. 

Normally, I'll be putting an erlenmeyer flask of wort and a bit of yeast on the stir plate. The idea is that as the magnetic stir bar in the flask spins, it keeps the wort moving and doesn't allow the yeast to fall out of suspension. It helps the yeast to be active and also introduces oxygen into the wort. These are perfect conditions for the yeast to flourish and quickly build up numbers before pitching into a brew.