StirStarter throws bar

[h22lude]

I've had a Stir Starter for awhile now and I can't seem to get the stir bar to stay unless I have it on a really low speed. I have been doing less than 2L starters and using the stir bar the Stir Starter came with (no pivot ring and kind of small). I now have a 5L starter and bought a 35mm stir bar which has a pivot ring on it. I'm testing a 4L starter with it and I can't use that on high speed either. It does move but doesn't cause any kind of funnel.

I guess a two part question...

1) Does it matter that it is at a low speed and now funnel with a bigger starter?
2) If it does matter, how do I fix it so it does throw the bar at higher speed?

 

[brick_haus]

Doesn't need to have a vortex to be effective.
Make sure the flask is centered on the stir plate. The stir bar should be in the exact center of the flask for best results.
Sometimes it helps to increase speed slowly, in increments, to help keep the stir bar from being thrown. Fluid resistance caused by sudden increases in speed will sometimes be enough to throw the bar.

 

[Cyclman]

No vortex is required.

But my stir starter easily vortexes a 2l starter. Weird.

 

[johnwpowell]

Try a smaller bar

 

[Konadog]

Question, has the stir bar been stored or attached to another magnet?

 

[Smellyglove]

Bigger oxygenuptake give a bigger growth..

Try swapping it for an oval bar. I find that the ones with the pivot rings give more resistance (and noise).

 

[whovous]

Try a smaller bar

This.

It seems entirely logical to use a larger bar with a larger starter, but it's not.

 

[Brewsncrabs]

Stir Starter recommends a 1" bar. I swear the website used to state not to use a bigger one as it would throw it, but now it just says 1" is all you need.

 

[h22lude]

The bar I was using with my 2L flask was a 1" bar with no pivot ring on it. That one wasn't creating a vortex. I'd say over 20% power would throw the bar. The flask is as center as my eyes can get it.

I have tried to slowly increase speed over time but that doesn't work either.

I stored the bar and magnet to pull the bar out of the starter away from each other.

I'm wondering if the magnets in the stir starter aren't placed correctly.