False bottom - is 40% open area too much?

[Brew_Meister_General]

30% OA seems to be the custom with false bottoms but is that the ideal amount or just the minimum useful amount?

I found some perforated metal with 2mm holes and 40% open space, but is 40% too much? My alternative is 1.5mm holes and 30% open space.

Thank you!
Luke

 

[augiedoggy]

30% OA seems to be the custom with false bottoms but is that the ideal amount or just the minimum useful amount?

I found some perforated metal with 2mm holes and 40% open space, but is 40% too much? My alternative is 1.5mm holes and 30% open space.

Thank you!
Luke

The hole size is the only real factor here... It needs to be small enough to prevent the crushed grain from coming through...no need to over complicate things.