Homebrew Recipe Search by Google

Links to Stuff

The Incredible Yeasty Beasty Stir Plate

This yet another project conceived in the pages of BYO Magazine, by far the best investment I made in my brewing hobby. Using a computer fan, simple power supply, a neodymium magnet from an old hard drive and a cigar box, sure beats the $200+ option. Although I’m a big fan of mail order homebrew supply shops, if I don’t have to give them my money, I avoid it.

Several of the books in the 3 Dog Library extol the benefits of using a stir plate to propagate your yeast if you make starters like I do (even for the average gravity brews) or if you harvest yeast from other beers. The stir plate keeps more cells in suspension rather than letting them drop to the bottom and congeal on the bottom of your yeast starter vessel.

So, here’s how I made mine:

First, I had the cigar box lying around, but it wasn’t my first choice of items to use. I wanted a small 12V DC power supply to run the fan and I had read that a portable hard-drive box was good alternative to the cigar box and it had a power supply. I managed to find one in the scratch-and-dent section of the local Micro-Center and picked it up for about $15. I got the thing home and extracted it from the disheveled box. It had nifty power and activity LEDs as well as a “wall wart” transformer pack and a power switch. The problem, I discovered was that the box was so cheap because it was steel. Not what I needed to try and put a spinning magnet in. I had to scrap that idea and pull the guts out of the hard-drive box and mount them in the non-metallic cigar box. Try and save a buck and spend two…

Second, I had a couple of computer fans I had planned on using, I would just test them to see which was running at the speed I wanted and mount the magnet on that one. They were both your standard fare 80mm fans from an old PC and both were fairly old. I started with one of the newer fans and found that it turned way to fast. I wanted to make a stir plate, not a chipper-shredder. I tried the second fan and it turned too fast as well. Just to add to my misery, I tried fitting the magnet to both of the fans and as it turns out, the magnet wouldn’t stick to the fans either. I had to find the magnet across the room a couple of times before I gave up. I went back to Micro-Center to buy a 120mm fan with speed control (hindsight, duh) so that I could slow the thing down. Another $15 spent on this low budget project. I stuck the magnet on the new fan and presto! Everything was back on track again. Well, almost...

Lastly, the stir bar was sourced from Northern Brewer and looks about the size of a Tylenol capsule. I made a point of not swallowing it by accident. The orange ring also from Northern Brewer is there to reduce vibration and movement; its a plastic coated iron ring and weighs a pound or more. I tried the thing out before fastening everything in place. Anticipation, and … Nothing. It seems that the magnet was too far away from the stir bar. I put spacers under the fan to raise it up inside the cigar box. I wanted to be able to open the lid, so I avoided fastening the fan to the lid and stubbornly worked to move the magnet closer to the underside of the cigar box lid. I used my daughter’s silly putty like “plasti-gauge” to determine how close to the lid I was getting the magnet.

I had achieved spacing the fan as close to the lid as was possible without scraping it. Still nothing. I determined that I needed a larger magnet. The one I was using was from a laptop drive and I was going to get an old clunker 5.25 inch drive and pull it apart to get the magnet. Not much use for a 20Mb drive these days. The magnet was much larger and unfortunately, thicker. I had to go back to spacing the fan again since the magnet was thicker, but now I had a working system with a variable speed control. The result is what you see here.

Huh?

I once made a half gallon yeast starter for a Strong Scotch Ale I made.

I started with 1 pint and after 3 days would pour off the top layer of liquid and add another pint of wort and shake it up.

Scotchtoberfest was 1.100+ starting gravity and finished out at about 1.034. Not what I ahd hoped for. I aged the brew in a keg with oak strips for a year at 34 degrees.

At about 9% ABV it was still a little rough around the edges and leaving the oak in the keg that long was probably not a good idea. The beer was to cloying and not bitter enough. Bad batch. I finally finished the keg about 3 years after initially brewing it. By that point I was very tired of drinking it and had started to look like Grounds Keeper Willie. Arrgh!