Mash stuck due to a porridge-like sludge

[kelper]

This was my first all-grain recipe. Unfortunately, I suffered a stuck mash. The liquor would not drain from the malt pipe and the pump stopped circulating. I had to scoop out all the grain and filter the 'porridge' through a brew bag to recover the liquid. In the brew bag remained some of the grain and a porridge-like sludge. There were no doughballs. I used 2.5 litres of water per kg of grain. It was a Landlord clone.

The grain was supplied ready-crushed. Should I have sieved it first? Any advice welcome.

I did get it sorted but lost at least 500g of grain/sludge and missed my target SG. 1.037 instead of 1.045.

 

[MmmBeer]

What system do you use, I'm presuming it's an all-in-one? I normally use 2.7 l/kg, as specified by the Grainfather software. I have had slow draining mashes, but never completely stuck, normally I close the ball valve slightly, which reduces the pump flowrate and balances the draining rate. Was it the Graham Wheeler recipe, just pale and black malt with no adjuncts?

There should be no need to sieve, just stir thoroughly as you mash in, I use a slicing motion with the paddle to break up the grain.

 

[kelper]

It's basically a Klarstein 45L Brauheld. I did stir and slice! https://www.klarstein.co.uk/Home-ap...Ltr.html?listtype=search&searchparam=brauheld

 

[The Baron]

What was the recipe ?
I use a higher amount of water to grain ratio than some suggest more like 4l to 1 kg approx. If you do get a stuck mash there are a few things you can do like adding oat husks to help separate the grain and if it still sticks try shoving a knitting needle to the bottom of the mash and create some small drainage holes before doing the arduous task of taking all the grains out. Over stirring the mash can also sometimes cause a stuck mash IMO

 

[kelper]

I was able use my paddle to clear the holes at the bottom of the mash pipe but it immediately blocked again. I added a lot of water to thin the gloop but it didn't help. Maybe the amount of water was too little? It was a 23 litre recipe in a 45 litre all-in-one.

 

[The Baron]

was there a lot of flour in the grain crush it does sound like it was a fine crush as it also must have been getting through the bottom mesh into the recirc pump to block it if it is a all in one system

 

[kelper]

It didn't block the pump. It stopped the malt pipe draining. It was a Landlord clone. The instructions only gave temperatures and times. No advice on water quantities. Recipe came from grain supplier. There was a lot of flour with the grain.

 

[The Baron]

It does sound like a crush that was a little finer that it should be for a all in one system. I once got a sack of 25kg from my normal supplier and it was for whatever reason milled finer than I had had from them before thats when I found the use of Oat Husks to help with the stuck mash. Just put that one down to experience and maybe change your supplier if it keeps happening as stuck mashes takes the pleasure out of brewdays or make your own recipes as you have more control

 

[MmmBeer]

Another thought, as well as the 2.5 l/kg, did you add additional water to fill the dead space below the malt pipe? Its 3.5 l in a Grainfather, likely to 5 or 6 l in your 45 l system.

 

[kelper]

Another thought, as well as the 2.5 l/kg, did you add additional water to fill the dead space below the malt pipe? Its 3.5 l in a Grainfather, likely to 5 or 6 l in your 45 l system.

Good point. I didn't. Will next time. It's 5L on mine, just checked. But I had no doughballs so I don't think it was a factor.

 

[An Ankoù]

That's a bit of bad luck, kelper, especially as it was your first. It does happen occasionally and you did all the right things to rescue it. I've heard that some brewers, especially States-side, tend to add rice husks to the mash to improve the filtering characteristics.

On another subject and talking about "porridge", who was the brave lad who tried fermenting the entire mash some months ago? How did it turn out?

 

[kelper]

Adding husks might help clear the wort but I don't think it would have helped in this case since the porridge formed at the bottom.

 

[The Baron]

Hi Kelper the husks are added to give little pockets between the grain for water to pass through it should help in the future. It was bad luck on your first but it is a learning curve and hopefully you will be able to judge if there is too much flour in your milled grain for next time. Good Luck

 

[kelper]

The grain suppliers have come back to me and said I should have used 16 litres of strike water. I used 12, just over 2.5l/kg. I did add 5 litres when it 'stuck' but it was too late.

Would that four, extra litres have made any difference?

What do most people use per kg?

 

[IainM]

Last time I did the TT landlord recipe it was a 22L batch (4.53) and I doughed in with 14L, so 3.1 L/kg, which worked fine. The 2.5 L/kg is at the thick end of the scale that is often quoted (2.5-4), and is for traditional mash tuns, not all-in-ones that have the dead space for recirculating. You might have gotten away with it if the crush was coarse, but it sounds like it wasn't. I think the extra 4L would have made a difference, as would some oat/rice hulls.

 

[BeerCat]

I generally mash with 4 or 5 liters per kilo and never get a stuck mash anymore and always get the correct mash ph. I started doing this after reading about full volume BIAB. Partly because i get a lot of boil off and because of issues like yourself.
Its a good idea to have some spray malt on hand when you start brewing in case you need to bump up your gravity points.

 

[Rakey]

I brewed a Landlord clone on Saturday on a grainfather, I always use 16L for strike water and 16L for sparging, as due to the grain bill being less than 5kg using 2.5L per kg wouldn't reach and pass down the overflow pipe and would cause a stuck mash and allow the bottom to run dry and block. Sounds like you needed to add more water to reach the overflow

 

[The Baron]

I brewed a Landlord clone on Saturday on a grainfather, I always use 16L for strike water and 16L for sparging, as due to the grain bill being less than 5kg using 2.5L per kg wouldn't reach and pass down the overflow pipe and would cause a stuck mash and allow the bottom to run dry and block. Sounds like you needed to add more water to reach the overflow

I do not think the water is meant to go down the overflow pipe as it is what it says a overflow pipe if the water is not travelling through the grain bed it will back up and go down the overflow pipe to stop the element boiling dry as a safety feature but the water is meant to travel through the grain bed and recirculate with the pump for a more efficient mash IMO

 

[Rakey]

I do not think the water is meant to go down the overflow pipe as it is what it says a overflow pipe if the water is not travelling through the grain bed it will back up and go down the overflow pipe to stop the element boiling dry as a safety feature but the water is meant to travel through the grain bed and recirculate with the pump for a more efficient mash IMO

At the start the pump will go faster than the flow of liquor through the grain bed, so as it builds up on the top plate it will go down the overflow to prevent the bottom running dry, as the mashing time progresses the flow will mostly go through the grain bed and the flow down the overflow will reduce. If there is not enough strike water in the mash or the pipe sits too high from the grain bed due to low volume then nothing will flow down it, the water will sit within and on top of the mash and result in running dry.
You are correct that the place it needs to go is through the grain bed as a goal for the process, but if it doesn't flow through fast enough and the top plate and overflow doesn't sit on top of the grain bed because its a small grain bill and low amount of strike water it will soon just run out at the bottom and all just stop due to not being able to reach bottom fast enough. Seen it happen before, and was talking to someone else who was having this problem just at the weekend.

 

[The Baron]

What you need to do is back the pump off so that it mirrors the flow through the grain bed. If you are having it running so slow and it is still backing up you are having trouble with the mash consistency, there are a few things you can do to improve this try stirring the mash a couple of times say after 5 mins and then after 10 mins if it is not improving. This issue is usually caused by a sticky or grain crush too fine with a lot of flour in it, if that is what you think is causing the problem try a different crush or add some oat/rice husks/hulls to separate the mash grains. I do know that it may on some occasions overflow down the pipe but that should be set a inch or 2 above your ideal grain re-circ level to protect the element from boiling dry but it is the initial problem that needs sorting. Most people do have to back off the pump from a full flow to get a steady re-circ level