Unusual Mash Problem

[bobtheUKbrewer2]

wsmith - I am not filling the bag at all. I am removing liquid to avoid overflow, but obviously I need to return this liquid, it is recirculating, butI do not wish to do it, and up to 4 brews ago I did not do it.

Bassman - no the borrom of th bag is 4 inches above the Burco bottom

dtashmore - the bag is bigger than th burco boiler, both in terms of length and diameter

 

[wsmith1625]

Have you tried stirring as you heat the mash? What's your water to grain ratio? I don't think you shared the size and model of your water boiler either. That would be helpful.

 

[SanPancho]

Have you asked your source for grains if they’ve recently changed their mill or mill settings? If the grist is too fine for flow, it will also block flow to the vast majority of the bag’s surface area. That means overflow.

 

[bobtheUKbrewer2]

I repeat that for many years I have used the same technique with no problems.

Wsmith, as purchased a Burco boiler holds 23 litres. Mine has been modified by welding on the top of another Burco boiler so that it holds 42 litres. I start with 33 litres of water and 10.5 lb of grain, ie a full volume mash.

San Pancho - since I start with maybe 6 inches of liquid above the grain, and as part of the initial heating cycle to reach approx 68, and as I run off liquid from the bottom tap to avoid excessive local heating just above the heating element, I believe you have diagnosed the issue. If the grain is too finely milled it will not allow liquid to flow through it - because - the diameter of the bag is greater than the diameter of the boiler.

I am purchasing a new 25 kg bag of crushed pale malt in a few days so will report if same issue occurs. If it does, I have already made a stainless steel vent that will be positioned between the bag and the inside of the bouler.

Sincere thanks to all contributors to this thread.

 

[micraftbeer]

I agree with some of the posts above. Your hot wort/steam/etc is trying to rise to the top and it gets trapped, giving you the overflow phenomenna. Maybe finer crush, maybe tired old bag that doesn't like to let stuff through.

Vent pipe outside the bag, new bag, not as fine of a crush, stirring of the whole mash when your burner is on to mechanical make an escape path for the heat, etc.