Beer Forum

This is my first time using my new equipment so I can't say how it will hold up over time, but for its first use it's very impressive. I have a 4L starter going in a 5L flask and this new stir plate is spinning it like a top.

If you get a chance, can you try it with a 1G jug with a domed bottom and see if the thing still holds the stir bar or if it just throws it? I have been using a 2L flask and a 1G jug, but the jug doesn't do the stir plate thing very well. I think it is just because the magnets aren't strong enough to hold it when the bar is that far away due to the domed bottom.

I think if you have a vessel with a concave/convex bottom you need a special bar to not have it be thrown. Some need a barbell type and others need one with a bumper in the middle. I am pretty sure straight bars will only work in vessels with flat bases.

NateBrews wrote:If you get a chance, can you try it with a 1G jug with a domed bottom and see if the thing still holds the stir bar or if it just throws it? I have been using a 2L flask and a 1G jug, but the jug doesn't do the stir plate thing very well. I think it is just because the magnets aren't strong enough to hold it when the bar is that far away due to the domed bottom.

The one gallon jug (or any domed vessel) will not work well for two reasons.

1. - the dome will place your stir bar further away from its magnetic pair than a flat vessel would, reducing the magnetic pull between the two magnets.

2. the dome forms a "dynamically unstable" scenario, where the stir bar will have to fight gravity in order to stay at the peak of the dome. So now centrifugal force will trying to throw the bar out to the vessel's side, and gravity will be trying to pull it down to the base of the dome (also the vessel's side).

If anybody knows of a supplier that ships to the UK please let me know.

Thanks.

They make bars in various shapes to help with non-flat vessels.

You can get bars like little barbells (disk on each end) which helps when you have domed (convex) bottoms. The 2 bands will more or less help keep the bar in place by pulling downward equally on both ends.

center pivot (or Saturn shaped) work well for flat bottoms or convex.

http://www.rosesci.com/Products/product ... tir%20bars