Low Mash Conversion Efficiency, would like some tips

[DuncB]

Found this picture from my review. I forgot the Anvil Foundry has this plate on top with multiple holes. This obviously helped spread out the water, and controlled how quickly I could pour the sparge water so as not to overflow the shallow part of the tube.

Very similar for the guten as well, with the bigger malt pipe I've got a lot more headroom when it isn't full. But similar sparge I just use the pipe coming out of my water heater to trickle distribute it.
I use that plate during the mash as well to try and stop the recirculate channelling.

 

[micraftbeer]

I haven't ever checked the mash efficiency / that it has finished but the fact there are drainings after sparge at 1.040 makes me think the issue is at the sparge.

A couple of things sinking in here after re-reading the thread.

1. Do you mean that you're measuring gravity coming out of the bottom of your malt pipe, while it's elevated and out of the wort, of 1.040 gravity? If so, it definitely sounds like you would benefit from better/additional sparging. I never recorded the gravity of these runnings when I was using these systems, but when I was doing fly sparging through a cooler mash tun, I know I was getting down around 1.010 at the very end of sparging. Of course, the closer your gravity is to 1.000, the better your sparge has been. There's a number down there though that you're not supposed to go below due to tanin extraction or something. Somewhat irrelevant in this discussion if you're still getting 1.040 gravity out.

2. Having reviewed a couple of these type systems in the past, I was skeptical of how well they worked with temperature sensor so close to the heating rings. So I ran some experiments on both the Mash & Boil and the Robobrew (V1 or V2) comparing what the unit was reporting as temperature vs what I measured with a hand-held thermometer in a test until filled with water. Between the two of them, the M&B bulk fluid temperature was actually warmer than the on-board sensor reading, and the Robobrew was bulk fluid temperature was actually cooler. I don't think this is likely your efficiency concerns, but worth noting while you're diving into details here. Attached are my plots for reference. The Robobrew had a built in pump, so that was running during these measurements. The M&B did not, so I measured it first with the water just standing, and then again after stirring it up well with my brewing spoon.

 

[DuncB]

@micraftbeer

Explaining 1
After I have put the sparge volume through ( similar to the way you showed in your photos), I lift the malt pipe out and stand it on a ferment bucket rather than drip on floor etc.
The liquid that drips out after this has gravity over 1030 and sometimes up to 1040. The volume about 1.5 to 2 litres.
This is what makes me think my sparge is not fully effective.

Regarding 2
I did check the temperatures and recalibrated the sensor when I noticed that it was boiling but reading only 98 celsius. Note this was not during the mash but for the boil. I have checked the temperature of the top of the grains with a separate thermometer and it is accurate. I run the pump throughout the mash.

I do feel the problem is with the sparge and the way that the water runs straight through the grain bed. Maybe I should be using a little less than 3 litres per kg of grain to mash and add more sparge.
Maybe try 2.75 litres / kg for a 6 kg bill that would be 16.5 litres in mash and then 19.5 litres of sparge. However I expect the sparge water would still run through at the same speed and so not extract that much more sugar.
I could only try batch sparging by putting all the grains in a different container after the mash.

I'm wanting to do some bigger beers to lay down for next winter but am reluctant to attempt a high gravity beer as I'm expecting efficiency will drop further given the current issue.

 

[slimshady95sox]

It sounds like you did a "no sparge," which will yield lower mash efficiency than a mash with a sparge (given same total water). But it wouldn't cause the kind of low efficiency you apparently got.

Who milled your wheat malt and how did the crush look? Wheat kernels are smaller than barley, and a reasonable mill gap for barley malt can be too wide for wheat, leaving too many uncrushed or under-crushed kernels.

Good point. I will keep an eye out for the crush of wheat next time. I dont have a picture of the crush unfortunately

 

[Smudgey]

I just had my lowest conversion ever because I didn't stir the mash in. 1.035 pre-boil, target was1.052 post boil. I violently underlet it when I accidently dropped the malt pipe while finishing milling directly into the mash. Then I got distracted with the mop. The result is the non-sparged doughy mass in the centre of the pic below.

I usually hit 80%ish but will be about 54% this time. I fortunately have 1.5kg LME on hand, but I'm regretting all the flavour I'm about to tip out. I was a fair way into the boil before I read the sample.

Have you tried some grains from throughout your mash tun? They should be uniformly dark & bland like the stuff on top and not light and starchy or sweet like half the grains I'm about to tip out right now...

Giant sweet doughball: