stir plate

[Butter]

I'm finally going to make starters for my beer. Is a stir plate a necessity for aeration or is it more a convenience? Couldn't I just use my O2 that I use on my wort?

 

[bessieflames]

The stir plate doesn't allow the oxygen to be depleted. By constantly stirring, it provides continual oxygenation which keeps the yeast in the growth phase. Aerating once and leaving it without stirring will work but not provide as much growth. The result is that you will need a larger volume of starter to get the same amount of cells. Check out Mr. Malty pitch rate calculator.

 

[Butter]

Oh ok, so constant aeration is key. Got it. Checked out Mr malty, but wouldn't load right on my phone. Thanks for the help.

 

[daksin]

Not necessarily. You can make more yeast grow in the same volume using a stir plate, but you can just make a larger starter and mix it every time you walk by it. Definitely don't need to spend any more money than you want.

 

[Butter]

Granted I don't want to spend it if I don't have to, but don't mind spending it if it will go to good use. Although I've seen the replies by other people who do the shake and it works for them. I'll try that first and if it works, the stir plate will be a luxury buy.

 

[theveganbrewer]

You could make a stir plate for about 10 dollars. The flask will cost a bit more, I think they are 10 bucks too.

 

[jusware]

The stir plate also keeps the yeast in suspension and helps make contact with sugars in the wort. In my experience starters get going quite a bit faster. I think the stir plate is one of the best things I've bought since I've started brewing. I would highly recommend one, especially if you ever plan on using slants or harvesting yeast from bottles. Mine cost me 50$ and that included a flask and a stir bar. I've also found that after pouring out my starter I can add wort to the flask and put it back on the stir plate and start another starter off tiny bit of yeast left in the flask. It'll pay for itself quick if you do that a few times.

 

[Butter]

Veganbrewer, how would I build a stir plate for $10?

 

[Butchv12]

I'm with you Butter --- for 10$ ? I'd do it for twice that!

 

[Butter]

I plan on using the 2L flask and making a minimum 1L starter for each brew. I'd be limited to 1500 ml starter size with the 2L flask right?

 

[beergolf]

You don't need a stir plate. You can just shake the flask every time younwalk by. But a stir plate is so much easier.

I got a Stir Starter stir plate and it works great. It was around 40 dollars. Worth it to me. I have used it to culture yeast from commercial brews (Bell's, Rogue, and Pranqster) so I figure that it has paid for itself.

 

[Exbeerienced]

What is the latest scientific evidence on this topic? The last I recall, it was the Mary Beth Raines experiment comparing stirring and aeration.

 

[theveganbrewer]

I used to shake every hour but the stirplate not only is easier, but makes more yeast. I easily have an extra 1/4 to 1/2 inch on the bottom of the flask after using the stirplate.

About the $10, this is what I did.

Get a 80-120mm computer case fan. Newegg is a decent place to get them on sale. In their email blast they usually put one on sale for 1.99 every week with free shipping.

I just checked and they have a number of them on sale either free after rebate or for 1.99 with free shipping. Even some LED light up ones.

Newegg.com - Computer Hardware, Fans & Heatsinks, Case Fans, Mail-in Rebate

Then you need to pick up a Stainless Steel Washer, 2 inches wide with about 1/2 or smaller hole in the middle. 25 cents.

Pick up some Neodymium 42 magnets at Ace or Hobby Lobby, or buy on Ebay. $5 or less. You can get 35 strength but you may have to do 3 on each side.

Get an old cell-phone charger 9v or 12v $2.99 on Ebay.


I used an old 50 CD-R spindle top to house my computer fan and magnets. That was free. You could pay 5.99 and get a radio shack project box if you wanted it to look nice. Also, others get on off switches and throttle knobs, but when mine busted during installation, I just wired the fan direct to the cell phone charger and have never had an issue.

You're going to epoxy the SS washer to the center of the computer fan motor. After it dries, place 2 neodymium magnets on each side of the center hole. You can epoxy them if you wish, but they should stick in place by themselves. You'll want to space them so the end of the stir bar (1" works good) sits in the middle of each magnet. With that done and spaced, wire up to the charger (yellow line gets nothing), put on the CD spindle cover (you may have to cut out the center a bit if it has an indention) and try to space it so the magnets are as close as possible to the top of the case. They should nearly touch the top of the plastic. That should do it.

Here is mine, it's not pretty, but that could be solved for 5.99. I've done 7 starters on this so far, from 500ml up to a 1.8l last night, no problems.

 

[Exbeerienced]

Can that puppy be rigged with an adjustable speed control?

 

[theveganbrewer]

Can that puppy be rigged with an adjustable speed control?

Yeah, I had one originally but I just took it off cause it worked without it. Just wire it into the splice off the power cord. If I ever get a thick wort, I just undo the wire nuts and wire in a more powerful 12v charger I have. Usually I just run on the 9v.

 

[Sulli]

I use a setup similar to this. With this setup you can turn just about any fan into a stirplate. The dimmer switch is the on/off switch as well. I use an old box fan I had lying around, removed the plastic grille, stuck some magnets on the hub, and laid a piece of 1/4 inch plywood over the frame. Voila. Instant stirplate.

[ame=http://www.youtube.com/watch?v=SmnPHQNwuFM&feature=player_embedded]DIY Magnetic Stir Plate - YouTube[/ame]