Beer Forum

As soon as I started to look at using liquid yeasts - and playing with Mr Malty's pitching calculator I could see that a stir plate produced the most yeast and possibly healthier yeast. Soooo after many googles and looking at other stir plate projects I did mine this week. It didn't hurt that in a previous life I was a electronics tech and did plenty of fabrication.

Harvested the rare earth magnets from an old hard drive - I had a 80mm fan - also found a 12v brick in a junk box. About $18 in electronics and had the plastic case built from parts out of the scrap box at a local plastics store. The case cost $10 including the bending and gluing. I did the fabrication in a "old timey" fashion ...

I'll have to figure out how to post some pics

Please do post some picts! Back in 07-08 I harvested the magnets, had a computer fan set aside... and then petered out on the project. I just "intermittently shake" my starters, and have had good results... but I definitely should get back onto the stir-plate track.

I work in a lab as a second job. They had an old heat/stir plate that the stir had gone out on. I asked if I could take it home and work on it. I was able to move some of the good parts from the heating side over to the stir side and got it to work (no heat). Now I have a laboratory grade 12"x12" stir plate that was probably about $1200 brand new!

I recommend getting a job as a lab tech.

i second lab stir plates! mine is the shiznits, and i like the ramp up, ramp down feature.

At a major on line auction site I bought a lab grade stir plate $35 and $10 shipping. I guess I could make one for less maybe but not by much. They hold value if you ever want to sell one.

Steve

Yeah -- If you can get a lab grade used stirrer for under $50 go for it. I worked as a lab tech all through college and they run from basic to programmable.

But if you are on a tight budget and can scrape up the parts you can build one for less than $30. I kept this very simple - I did get a great deal on the having the plastic case constructed by a local plastic shop using parts from their scrap bin - total $10.

I did my first starter this weekend and see that I have to fix one thing - the stir bar will occasionally get thrown off to the side of the flask (2000ml flask). For about $8 I found rare earth magnets 3/8" or 1/2" disks with adhesive on the North or South side. I'll do that next month - see link(s) below. I used a 80mm fan I had laying around at some point it will fail and I might move to a 120mm fan. But it works and its simple

shot of top -- key here is to glue a washer to the fan and the magnet just sticks to the washer (I did add 2 glue dabs just in case)


Side Detail shot


Test Run


First Starter - 2000ml Flask


This is the site I used as a reference - and the circuit design
http://www.backyardbrewers.com/?p=26

Rare Earth Magnets - adhesive on North or South
http://www.mcmaster.com/#rare-earth-magnets/=6eqrrl



This is a super simple design - I would use a 180mm fan
http://www.pbase.com/mrfebtober/diy_stir_plate

Remember you don't need a super vortex - the idea is to keep the years in suspension and improve the gas exchange at the surface

Prost!