Ring Around the Mash

[Matt@Bauhaus]

Not sure if this is the right forum for posting this topic, but here goes...

Every once in a while, we see a pretty significant "ring" around our mash after we're done lautering (see photo below). We leave our rakes on during our mash (at the lowest setting on the VFD), and periodically change the rotation of the rakes while mashing. The ring doesn't seem to affect our efficiency or lauter, but we can't figure out why this happens. Anyone else experience this or have any comments/suggestions?

[Bbump22]

I've had this happen a few times. Usually varies based on the weight of my grist. Typically I am able to reverse the rakes and it spreads it back out to the sides for me. If my bed is already set I just use a mash paddle to gently spread it back to the side.

[dick murton]

The bed is compacting because your rakes are not able to keep the bed porous enough for the speed you are running off at. You do not appear to have many rakes, or strakes on the rakes to help lift and break the bed. On big brewery lauters, there are sufficient rakes to create tracks in the bed less than an inch apart, and the strakes on the rakes effectively overlap, so every particle of grain in the bed is moved by one or other rake.

The only option without spending a shed load of money on new rakes and controls, is to slow the runoff down. You will probably find a considerable improvement in extract as the sparge water then drains through the bed, not down the side of the bed. A coarser grist will also help if you are not beating the mash to death in a separate mash mixer first.