Sunday, February 3, 2008

The Stir Plate Project

In a previous post, I wrote about a yeast starter I created. This was a great learning experience and it really helped out my IPA I created. A yeast starter helps get the fermentation process started quicker. By growing the yeast culture, instead of just throwing in a White Labs tube, there will be more yeast further on in their life at pitching time. This will help drop the specific gravity down, increasing the ABV and drying out the beer. So what can one do to help out the starter even more? Keep the yeast starter on a stir plate.

What is a stir plate?

In short, a stir plate is a piece of equipment that continually stirs liquid (in our case, wort). With a yeast starter, the stir plate keeps the yeast in suspension and does not allow the yeast to settle. It also continually adds oxygen to the yeast starter. This helps keep the yeast growing and reproducing. As long as there is oxygen in the yeast starter, the yeast will reproduce.

One issue with stir plates is their price. A retail stir plate can go anywhere from $100 USD to $500 USD. If you’re a home brewer like me, spending a couple hundred on a stir plate is not an option. But how can you get the benefits of a stir plate and not pay the premium price. My answer, I built one.

After searching the web, I found hundreds of people who have built their own stir plates. These ranged in price from cheap and simple to complex a little more pricey. Still, most were under $50 USD. I went the cheap route.

I discovered a page from Dave Trumbell and the Stir Plate he created. I pretty much just copied his. In the end, the price ended up being around $22 USD, but I had some help. I ended up having some parts around the house. I took apart an old Hard Drive from a computer and stole the Rare Earth magnets from within. I also had some old 6-volt power supplies to old electronics that I kept “just in case”. Steve Hawk had a couple computer fans to add to the mix. I ended up making 2 stir plates. One for me and one for Steve.

Here is a video of the stir plate in action:


Steve Hawk said...

Hey Jeff, Nice Work!
I have a yeast starter sitting on mine right now. Probably going to try to pitch tonight using Mr. Malty's suggestion of pitching the starter during 12-18 hours. I'll let you know how it turns out.

Tom Hargrave said...

Great stir plate for the price.

We just launched our own stir plate - it costs more than yours but understand that some homebrewers don't have the skills you have.


Nickname unavailable said...

do some research before purchasing anything from . . . that company and owner have a history that ain't good. Search on

Chris said...

FWIW is associated with a man who cannot seem to keep up with orders on his other site

He is well known (disliked) due to his shoddy business practices and more information on him and his sites are available on

He even has his own sticky warning people against using him.

Lars Mudrak said...

This looks great, I followed the link to the web site, are there any written instructions to go along with it? I'm pretty UN handy when it comes to wiring and electricity... Thanks!

Lars Mudrak said...
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