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Stir Plate

I am looking for suggestions on a stir plate, the one I have keeps throwing the stir bar, will a longer stir bar help with this? Once the yeast got going, the vortex disappeared and the stir bar appeared to be mired in the yeast at the bottom of the flask.

Are you using a flask with a flat bottom? I use a 2 liter flask(about 6" dia.) with a one inch bar & have no problems. Tried a large pickle jar, but the bar wouldn’t stay in the middle, due to the convex shape of the jar bottom. :cheers:

Also you may be going to fast, you don’t need a large vortex just a dimple will work. The main idea is to keep the yeast in suspension the added o2 is a bonus.

I use an old apple juice jug with a bump on the bottom and a 1" stir bar with a band in the middle. No issues for me.

Maybe you need a barbell or cross style stir bar.

Sounds to me like you may need stronger magnets or they may just need to be positioned closer to the bottom of your flask. Stir bars receive quite a bit of resistance with some of the high flocc. strains as your population grows.

I have a computer HD magnet glued to an old computer fan, sitting about 1/2" below the level of the bottoom of the flask. I have the best/consistent results from a 1" bar, a 1.5" doesn’t do as well, it throws off after a little while, and a 2" won’t work at all. There is a small rise in the center of my 2L flask, so I off-set the flask just a little bit so that it spins just off center. That makes a great difference, and will run for hours without any problems. It’s sometimes a little aggravating, but usually works well enough that I don’t feel the need to spend big money on a commercial stir plate.

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