Mash stuck due to a porridge-like sludge

[kelper]

I think I will add more strike water and change to a supplier who does not suggest I contact the all-in-one manufacturer to find out why I got a stuck mash! I will choose a grain supplier who is less defensive and more helpful. I never asked for money back, I just asked for advice. I still suspect that I got the scrapings from the hopper.

 

[The Baron]

I too once got a 25kg sack which I had got from my normal supplier and the crush was visibly different from normal, when I asked them they said nothing had changed at their end but it was well finer and caused stuck mashes I had not had before. When I ordered my next sack it was back to normal and has been ever since, makes me think I got the end of a badly set crush too. Put it down to experience Kelper and always have some oat husks in your supplies to aid any future stuck mashes. I bought a 5kg sqack of husks and have never really had to use them since but they are there incase I get a bad crush in the future

 

[kelper]

Baron, are husks any use once the mash is stuck or would you have to have to put them in before?

 

[The Baron]

you should add them before in a ideal situation but yes you can stir them in to the mash if it is sticking they also keep for a long time

 

[foxy]

Definitely try not to let the wort flow down the overflow, choke the valve until the level is steadily going through the grain bed. The more fluid the mash the less chance of a stuck mash even with a lot of oats, as has been mentioned, up the base malt to compensate the loss in efficiency.

 

[Rakey]

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

I've been using a grainfather for 4 years and I've never backed the pump off as you call it, the pump should always operate unrestricted, the red valve is not a throttle to control pump flow, what it does is restrict and block flow and restricting will put extra stress on the product as its not a throttle that is linked to the power and speed of the pump like you get say on the Blichmann Rip Tide pump. Its certainly not something that the guys at grainfather teach you to use or tell you to do on their product, so it is not something that I would recommend or teach others to do.

 

[kelper]

Throttling the discharge of a centrifugal pump REDUCES the load on the motor. And, anyway, the pump is a mag drive. Throttling the input will do no harm either but it will increase the likelihood of a blockage as you say. My Coobra has two discharge valves and these can both be throttled.

 

[Rakey]

I think I will add more strike water and change to a supplier who does not suggest I contact the all-in-one manufacturer to find out why I got a stuck mash! I will choose a grain supplier who is less defensive and more helpful. I never asked for money back, I just asked for advice. I still suspect that I got the scrapings from the hopper.

More strike water will solve the issue.
I doubt you got scrapings, most recipe packs are made individually and bespoke, they are by where I get my kits from they even have a video that shows how they make their kits. You'll always get some flour like substance in any milling, and it won't do you any harm, just mix the bag before using it as the smaller particles will always fall to the bottom of the bag.

 

[foxy]

Agree with above, Robobrew, Grainfather Klarstein, HopCat, etc, etc, all have the same pump, and as stated they are mag drive the only downside to throttling back is the ball valve, they weren't designed for this, but I would guess everyone does it.
The small particles will not be a problem, the wort is recirculating, they go through the pump and dumped on top of the grain bed, a natural filter. I dough into 34 litres of water and skip the sparge, the loss in efficiency gives peace of mind knowing I am getting a better wort.

 

[PhilBrew]

Hi kelper

What do most people use per kg?

... when I first got one of these all-in-one machines (in my case a BrewDevil) I found @the baron's advice over there (link) very useful, and it certainly got me in the ballpark. I've since done a few brews and adjusted my assumptions on findings of actual losses (as you will undoubtedly need to, to match your Klarstein and your brewing practices, whatever advice you get on here) ... I've also moved to calculating strike water based on the formula: 6 + 3 lts per kg of grain ... which I think gives me a little more consistency of mash consistency, for differently sized grainbills, the 6 lts representing the volume under the grain basket on my BrewDevil (the amount of liquor I can have in the machine before any grain added would even get wet ) and then there are 3 lts per kg on top of that in among/around the mash ... as it happens, both the 4.5lts/kg and 6+3lts/kg formulae give similar amounts of strike liquor for "middling" grainbills, so the baron's numbers would be a good place for you to start out for next time, recognising that "your mileage" will probably vary

I also find I need to throttle back for the first 10-15 mins of the mash, I presume it's while the grain bed settles down, and then I increase the flow slowly once it's flowing smoothly.

Cheers, PhilB

 

[kelper]

Agree with above, Robobrew, Grainfather Klarstein, HopCat, etc, etc, all have the same pump, and as stated they are mag drive the only downside to throttling back is the ball valve, they weren't designed for this, but I would guess everyone does it.
The small particles will not be a problem, the wort is recirculating, they go through the pump and dumped on top of the grain bed, a natural filter. I dough into 34 litres of water and skip the sparge, the loss in efficiency gives peace of mind knowing I am getting a better wort.

Is that for 23 litres final volume?

 

[kelper]

I'll write a full review of my kit soon. Here's a picture of the setup for sparging.

 

[kelper]

Hi kelper
... when I first got one of these all-in-one machines (in my case a BrewDevil) I found @the baron's advice over there (link) very useful, and it certainly got me in the ballpark. I've since done a few brews and adjusted my assumptions on findings of actual losses (as you will undoubtedly need to, to match your Klarstein and your brewing practices, whatever advice you get on here) ... I've also moved to calculating strike water based on the formula: 6 + 3 lts per kg of grain ... which I think gives me a little more consistency of mash consistency, for differently sized grainbills, the 6 lts representing the volume under the grain basket on my BrewDevil (the amount of liquor I can have in the machine before any grain added would even get wet ) and then there are 3 lts per kg on top of that in among/around the mash ... as it happens, both the 4.5lts/kg and 6+3lts/kg formulae give similar amounts of strike liquor for "middling" grainbills, so the baron's numbers would be a good place for you to start out for next time, recognising that "your mileage" will probably vary

I also find I need to throttle back for the first 10-15 mins of the mash, I presume it's while the grain bed settles down, and then I increase the flow slowly once it's flowing smoothly.

Cheers, PhilB

Thanks. All noted.

 

[foxy]

Is that for 23 litres final volume?

I do get 23 litres final volume on low gravity beers 21 litres higher gravity.

 

[Tony Palmer]

Problem is due to an over milled malt or possible a friable malt that has created a lot of fines. The technical term for this is Tieg. - a grey coloured porridge that blocks run off. Further dilution would have helped a little but it is really your raw material that caused the problem.

 

[The Baron]

There's no difference between restricting the flow by using a valve on the output and restricting the flow by having to pump the water higher. Both just increase the head pressure and won't damage the pump. Restricting flow by putting a valve on the input can cause cavitation, which can damage the pump. I would always recommend to throttle the output of this type of pump to give a match between mash flow and re-circ and if you watch most of the video's re all in one systems you will see that all adjust the flow to match mash re-circ or for sparging if using a pump. As I said previously and concurred by Tony Palmer it is the grain crush that is the main problem. Full bore on the pump is usually too much on most mash/grainbills unless you have a perfect crush and grainbill which is like a perfect storm once in a lifetime as every recipe is different and some are notoriously bad to mash depending on the grains used

 

[kelper]

Problem is due to an over milled malt or possible a friable malt that has created a lot of fines. The technical term for this is Tieg. - a grey coloured porridge that blocks run off. Further dilution would have helped a little but it is really your raw material that caused the problem.

Thanks. You're right, it was grey! I will look more carefully at the grain next time and not pour it from the bag, I'll scoop it up with my hands or a slotted spoon. The fines stuff can go in last.

 

[The Baron]

Hi Kelper if it is a fine crush with more flour than a normal crush I would sieve it out as you have suggested and throw rather than adding it and then add a little more grain to compensate for this

 

[kelper]

Thanks Baron, it was a reputable supplier but I will not use them again until I know if it was my technique at fault. It was a standard crush.

 

[northof49]

I've read that one can dough in by underletting, lowering the mash pipe with grist into the strike water, and that doing this reduces the likelihood of a stuck mash. I tried this on my last batch, and used a cutting motion with a mash paddle rather than a stirring motion and my mash didn't get stuck and had much better flow. There was also no evidence of dough balls. Could be worth a try if increasing the strike volume doesn't solve the problem.