I ordered a 1/8" magnet for my homemade magnetic stirrer. I got 2 of them so put them side to side. Still waiting on the stir pill to try it but, wondering what you guys used for them?

Most use the magnets from a computer hard drive and a power supply fan for the fan.

Forgive me for asking, but why use a magnetic stirrer? What is used for and what benefits do you get from it?


-J

It greatly helps yeast propagation in a starter. Keeps it oxyginated & off the bottem. Makes more yeasties!

OH COOL!





-J

We used magnetic stirrers in Microbiology class when we needed a lot of yeast for various projects.

They work pretty well.

Please post pictures when you finally have your stirrer up and running.

- Scott

I am curious how much better it will make my starters since I can get a 10gallon batch fermenting real quick w/ doing it old way. Oh well if's its no better at least I didn't drop $200 on the stirrer.haha

How big are magnets from computers that they use?

The magnets from the computer harddrive are pretty small. However, they are neodymium, or 'rare earth' magnets, and are extremely strong. When I made my stirrer, I had some neodymium magnets lying around, and used them. I had to glue the magnets on the fan several times before i got the most optimal position for them. I used a cut bolt for my stir stick for about a week before I got a true magnetic stir bar, and it was something of a dissapointment. It would stir, but you could not turn the fan on high without losing the bolt. Once the stir bar came in, it was much more satisfying. I now get a wonderful SUCKING sound as the water tornado is pulled all the way down to the stir bar. Its very neat.
Does it make better yeast starters? Yes and No. If you make a yeast starter by putting an airlock on a liter of 1050 gravity wort until it ferments out, then yes, you will get a CONSIDERABLY FASTER starter, with healthier yeast cells. If, however, you constantly aerate your 1020 gravity wort by shaking it, you will not get a better starter. Just one that requires much less work.
The idea of the stirrer isnt to make large high gravity starters. Its actually used to 'step up' yeast starters from a few cells from a slant or petri dish. Using lower gravity wort and high oxygen content through stirring, the yeast cells remain in a state of aerobic fermentation, which is necessary for rapid yeast propogation.
I hope your stirplate build goes well. My wife says that this is by far the 'coolest' thing that I've ever built. My son loves throwing the stir bar in a glass of water and making it 'suck'.

On a side note....Due to a fortunate mistake, I have a few (3) extra stir bars than I actually ordered. If anyone in the lower 48 needs one, drop me a PM, and when I get home I'll ship one to you. Im trying to spread a little good karma around the Brewers Roundtable, so this will be completely free. Please only PM me if you have a stir plate that needs a stir bar, or are building a stir plate and will require a stir bar. These things are pretty useless for anything else.

Cheers
Dave

vanwolfhausen (I love that movie!), what kind of magnets did you order? (ie - neodymium, ceramic, alnico...?)

GuitarLord5000 wrote:vanwolfhausen (I love that movie!), what kind of magnets did you order? (ie - neodymium, ceramic, alnico...?)

I used a rare earth magnet and it is strong for it's size but, still dont know if I need a bigger one so better to have it.haha

Beerfest is my new Animal House in regards to fun drinking movies that I have seen more than I would like to admit.haha

Wild....
My first trial, I had my magnet (only one) situated like yours. The problem I had with it was, the stir bar would not spin on center, and at high speeds, the stir bar would get thrown off track.
I hope that your stirrer doesnt suffer the same problems that mine did. However, if you find that you are having the same problem that I did, let me know and I will send you two fragments from the magnets that I have. They are considerably smaller and lighter, and you get both poles (MUCH more balanced!). If you align them correctly, you can get a near perfect spin. If you find you need them, I'd be happy to send them as soon as I get home. Consider it 'Good Karma'.

Cheers
Dave

GuitarLord5000 wrote:Wild....
My first trial, I had my magnet (only one) situated like yours. The problem I had with it was, the stir bar would not spin on center, and at high speeds, the stir bar would get thrown off track.
I hope that your stirrer doesnt suffer the same problems that mine did. However, if you find that you are having the same problem that I did, let me know and I will send you two fragments from the magnets that I have. They are considerably smaller and lighter, and you get both poles (MUCH more balanced!). If you align them correctly, you can get a near perfect spin. If you find you need them, I'd be happy to send them as soon as I get home. Consider it 'Good Karma'.

Cheers
Dave

Thanks for the offer Dave and the heads-up. The magnet isn't glued and the stirbar I'm waiting for is just the standard for a 2L flask. I have several magnets and I beleive I can fit 2 on if forced. I also have a backup fan just in case.

Thanks,
Wild

Going through some older postings.... I would like to see pictures of Wild's working stir plate. And any one else that has built their own. I have a few fans, and hard drive magnets, so I'd like to build one. And you know pictures are worth a thousand words.