Stir Bar w/ Center Ring _x000D_I use two of the vortex with 2-1000ml flasks with the yellow ridge stir bar, in each._x000D_I start on high, which starts a strong vortex, then turn dow to maitain a strong stir, and it works great. Start both 24 hours before pitch, and in less then an hour, I have very strong activity._x000D_Use 3-7.5 and 1-5.5gallon, buckets for primary, for red wine, then transfer to 100 liter SS tank, for 3+ months, seconday on 1-poundof blended oak cubes.

I use it in a 5 liter flask at moderate speed so it doesn't get thrown. It stirs up the entire bottom so the yeast stay in suspension.

I have a 5 liter lab grade Erlenmeyer flask and bought this because I make big starters for lagers. At full speed on my stir plate I can make a huge vortex, though the stir bar occasionally gets thrown to the side.

At low speed it doesn't get thrown as easily, at high speed it gets thrown in a minute. For the 5L flask, place it off center so the hump isn't directly under the stir bar.

The big one ends up getting thrown all the time. And the small one works great , at low speed, in a 2ML flask._x000D_I've not tried a 5ML flask, maybe it would be useful there.