BIAB grain mill spacing and bag microns?

[jsulmar]

I understand that mash efficiency can be improved with small mill spacing. Would like experienced advice about optimum mill spacing and bag microns.

 

[jtratcliff]

I'm not sure you'll get an "optimum"... In general, the finer the crush, the better/quicker conversion you'll get and the finer the weave of your bag, the fewer grain bits will make it through into the wort.

However, finer weave is also slower draining... and too fine of a crush (i.e. flour) can clog the fine weave bag or get through the course weave bag.

So you need to sort of find the combo that works for you. I think forum-favorite wilser bags are around 200 microns... I have bags that range from 120-250 microns.

I use a corona mill which I tighten until the teeth touch. This gives me fairly small pieces and a little coarse flour.

 

[IrondaleBrewing]

I understand that mash efficiency can be improved with small mill spacing. Would like experienced advice about optimum mill spacing and bag microns.

I have a Mighty Mill 3-roller and set it as small as it will go, which apparently is 0.025" even though the adjustment dial markers on the mill don't align with reality. That gives me a crush that sounds similar to what @jtratcliff is describing. I use a 400 micron brew bag and that works well for me with that crush, I typically get about 70% efficiency (have had as high as 75%).