[tschmidlin]

I think you can get something cheaper through a lab surplus outlet.  I got an old heated stir plate for $50 online a few years ago.  The nice thing is you can boil on it while stirring.

[majorvices]

That's how I got both of my stir plates (they are heated too) but I doubt they would work on a 5 gallon carboy.

In my case, I'm willing just to spend the money rather that hunt around on some site for days or weeks.

[tschmidlin]

Fair enough, you have your priorities.  Mine will stir a carboy though, if you use a good enough magnet on the inside.

[gmac]

Starters aside, am I wrong that if you were to use this for "dry hopping" as the flyer suggests you'd end up with an oxidized mess? 

[tschmidlin]

No O2 means no oxidation, so you'd have to make sure it was purged well.  I wouldn't bother for dry hopping them.

[phillamb168]

WTF, dry hopping? Do they know what that means? How would you use a stir plate to dry hop?

[majorvices]

WTF, dry hopping? Do they know what that means? How would you use a stir plate to dry hop?

I'm guessing the point is to keep the hops in suspension to get more contact time with the beer. Other than that I'm lost. Certainly doesn;t seem necessary.

Tom,what size magnet are you using on your stir plate to stir a carboy? You ever try it at 5 gallons?

[tschmidlin]

Tom,what size magnet are you using on your stir plate to stir a carboy? You ever try it at 5 gallons?

Here it is with 5 gallons of water.  This is not my heated stirplate, this is a non heated one, but it works the same.  This model is a Corning PC-353, painted red to make it work better.  I still need to add flames to the sides, do you know where I can get some flame stickers?  The heated one is a PC-351.

First we have the 35 mm barbell:


Here it is in action:


Here is the depression on the top to show it is working.  This one can't go much faster or it throws off, but you could use a barbell much larger than one inch and get a stronger vortex if you wanted to:


I switched to a 1.5 inch octahedral with a pivot ring.  It could go faster without flying off the magnet, and pulls a better vortex.  Again, you could go with much bigger than a 1.5" bar in a carboy, it's just what I have because I usually don't use larger than a 4L erlenmeyer.

[narvin]

That's how I got both of my stir plates (they are heated too) but I doubt they would work on a 5 gallon carboy.

Unless you made it out of a PC fan, I think most stirplates (lab models) would work through the thicker glass of a carboy.  If the problem is that you can't balance a carboy on it, maybe you can build a scaffolding around it?

[majorvices]

Well shucks - I guess I'll have to give it a try. Thanks fellas.

[PSUhomebrewer]

If you are seriously looking at investing in equiptment to grew yeast at large scale, I would recommend lookin for a shaker table or incubator instead of a stir plate. When you start growing yeast the more O2 the better, since at large pitches you will want to decant off the liquid an just use the slurry. With this in mind, most stir plates do not create enough surface area to keep the O2 levels high since most do not have the rpm to throw that much liquid out( basically you want to see the magnet as dry as possible looking down from the top. A shaker table set at 225-250 rpm is the standard when culturing. At this you will almost see the liquid double in height in the container giving you much higher cell counts.
Just remember your makin yeast in the starter not beer, thus fermentation is not a good thing since it cost the yeast more (biochemically) than simple respiration.