Quad Stir Plate

I made this a couple years ago. The goal of this project was to build 4 stir plates for under $100 total. I used the basic design you see all over this site using PC fans, PVC pipe, NdFeB magnets (I could only get 3 hard drive magnets), a voltage regulating chip and a used external hard drive power supply.

The frame is made from wood left over from manufacturing box springs. The lid is a 2'x2' thin plywood from Home Depot. Handles and hinges are also Home Depot. The hinges also function as magnet holders.

The only 'innovation' (if you can even call it that) I made was to use combination potentiometer+switches so I could individual control each stir plate. This also forced me to use a different resistor value combination than the stock design since this was the only cheap pot/switch in stock.

If anyone is interested in more details I will post.

If you're having to do 4 starters at a time, shouldn't you just open a brewery? Lol

Seriously though. What kind of fans/bearings are you using, and have you put any consideration in to using larger or performance grade fans to allow larger starters?

Yeah, while it certainly appears you're proud of and enjoyed building this (which at the end of the day all that really matters in this hobby) I can't fathom ever needing to create 4 starter at once. If you do brew multiple batches in a day, can't you just make one starter a week or so ahead, let it ferment out and stash it in the fridge 'till the next brew day? Congrats on your creation. I couldn't do it, nor can I see the reason to.

When I made this my buddy and I were making 2x10G batches in a brew day, about once every 3-4 weeks or so. We only had 5G fermenters and 2L flasks. The primary reason for this set up is it makes it easy to make 4 starters for 4 fermenters at a time without much notice. Second to that is that we had started to make lagers, and unstirred starters couldn't come close to the pitch rates we needed when making 20G in a day. Obviously if you're only making the occasion 5G batch this is way overkill.

The fans i used were these. They've doubled in price in the last 2 years but are still cheap: http://www.newegg.com/Product/Product.aspx?Item=N82E16835150007

I've never tried to spin more than about 1.7L in a 2L flask with this, but i sized the platform to handle 4x5L, and although I've never attempted to spin a 5L flask, I would think it could handle it as is.

Just saw this from a link from another post. This is awesome! Very nice creation!

Cheers,

John