OK, so I've been doing all-grain for a while now, and have been looking for new ways to improve the quality of my brews. The things I've identified are: making starters, better oxygenation of wort, better temperature control (the peltier thermoelectric fermentation chamber turned out to be a bit under-powered, but we'll save that for another post). I think making starters will have the greatest impact on my beer quality, and it may also save me money since, at the same time, I think I may start "washing" and re-using yeast, which is by far the most expensive ingredient. I've done small starters before, using a mason jar covered w/ foil that I just shake periodically, but I'm looking to do a little better, so I built a stir-plate. Parts list as follows:
(1) computer fan
(1) potentiometer
(1) DC spst lighted switch
(1) dial knob
(1) cigar box
(1) DC adapter
(4) bolts w/ nuts
(4) nylon washers
(2) neodymium (rare-earth) magnets
hot glue
(1) teflon magnetic stir bar
I bought all of the electrical components, switches, knobs, etc at radioshack. I picked up the wooden cigar box for free from my local liquor store. And, I found an old DC adapter in my box of wiring junk. I bought the magnets at Ace Hardware, and I bought the stir bar at Austin Homebrew Supply.
I drilled four holes in the top of the cigar box for mounting the fan, and holes in the front for the switch and speed knob.
The fan is mounted on the under-side of the box lid. The two rare-earth magnets are hot-glued to the spinning hub of the fan. Notice I ended up using a different fan than what I started with. The first one spun too quickly, and kept throwing the stir-bar.
Success!
My first yeast starter on the stir-plate!
