Low Mash Conversion Efficiency, would like some tips

[slimshady95sox]

Hey guys,
Just here trying to learn and improve my brews.
Basically, my problem in the last brew was low mash conversion, which is what I believe led to my Brewhouse Efficiency of 48%.

I mashed in at 152 F, with 6.75 gallons of water single-infusion ( i did this for the sake of simplicity but I suspect it is part of the reason for the low efficiency)
and the grain bill was 5 lbs US Wheat Malted, 4lbs 2-row, 1lb Flaked Wheat, 0.5 lbs rice hulls = 10.50 LBS of Grain.

I added salts to my water for the profile as well as checked the Ph, which seemed like it was right on point (assuming my instrument for measuring isnt flawed). Also, the grain bill was crushed for me by the shop, which I believe was properly crushed since they have a good rep, but I could be wrong (maybe next thread I will post a pic of the crush to check)

So, my question is, is the single-infusion with that Water-Grain ratio the culprit? Does that really make a difference in the conversion or should I look elsewhere for improvement?

THANKS!

 

[VikeMan]

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.

 

[doug293cz]

Did you measure the end of mash gravity (prior to any sparge, or other water addition?) Did you sparge, and if so, what was your sparge process. What were your pre-boil volume and SG?

Single infusion isn't the culprit. You can get 100% conversion efficiency (mash efficiency will be lower because of lauter losses) with single infusion - if your mash is long enough. pH within reason will not have much effect on conversion efficiency, although if it is way off, conversion can be adversely affected.

Brew on

 

[CascadesBrewer]

Are you brewing BIAB?

Grain crush tends to be the top driver of efficiency with BIAB, and with other similar methods. Most shops tend to crush a bit coarse. I suspect you can find lots of thread on efficiency around (especially over on the BIAB forum).

 

[Spundit]

IMO grain crush is the #1 suspect when troubleshooting low effieciency. A couple of the most popular online homebrew places have a very course crush with barley. I suspect it would be even worse with wheat.

 

[DuncB]

You don't mention how long you mashed for?
How much liquid went into your fermenter? and at what gravity?
Looks like 10 lb of grain to me, although the hulls are useful for that mash.

Do you squeeze the bag?

You seem not totally confident about the pH meter, has it been calibrated recently and stored in storage medium?

Did the water recipe suggest any acid additions? along with the salts?
Agree with @VikeMan the wheat often best to ask for that to be crushed separately then you can assess whether they have done their milling correctly.
It would have drained and vorlauf very quick I'd think if that amount of wheat wasn't really crushed well, it would have been slower than a non wheat bill if it was crushed fine.

 

[RM-MN]

The top 3 reasons for poor mash efficiency are:
1. The crush of the grain.
2. The crush of the grain.
3. The crush of the grain.

All other factors are far below this. Since wheat kernels are smaller and harder than barley, crushing them with the same mill at the same settings means they are not crushed fine enough. The only answer if you plan to do other beers with plenty of wheat is to get your own mill and change the setting between barley and wheat.

 

[MicroMickey]

water to grist ratio X temperature X mash pH X time = mash efficiency. Go back over the formula; something is out of kilter. As far as the grist, it was always touted that the crush should reduce the average grain kernel to about 5 pieces. These days too many want to reduce the grain bill to powder. Everyone seems to want to look for their lost keys under the street light instead of where they dropped them.

 

[Bill Tong]

Brewhouse efficiency is measured as the proportion of sugars of the total available in your grist that makes it into your fermenter. So trub loss makes a massive difference. For instance, if your post boil volume is 5.5 g and you have .8g trub loss, thats a 14.5% loss in brewhouse efficiency.

I do full volume mashes with quite a fine crush, i stir during the mash and get 75%+ mash efficiency.

 

[MicroMickey]

I didn't offer that as a real mathematical formula. These are the components of a mash. Each has a major effect on the overall performance of the mashing. If you focus on what's important, many of your problems tend to vanish.

 

[CascadesBrewer]

I didn't offer that as a real mathematical formula. These are the components of a mash. Each has a major effect on the overall performance of the mashing. If you focus on what's important, many of your problems tend to vanish.

Though I think BIAB has proven that as long as your mash is not too thick (above 1 qt/lb), that thin mashes have very little impact on efficiency.

Grain crush that is as fine as your system/process allows seems to be a clear driver of efficiency. I saw this back even when I was fly sparging and getting pre-crushed grain from different sources. Without knowing what process the OP is using it would be hard to say what other factors are involved...sparge rate, channeling during recirculation, wort lost in dead spaces, not draining/squeezing bag, etc. I would bet that grain crush (especially with the high percentage of wheat) is the main issue.

In my experience, the impact of mash pH seems overblown. I now know that without adjusting my pH, my mash pH used to vary from around 6.0 for light grain bills, to 5.0 for dark beers. Adjusting pH has improved my beers, but I never noticed any real impact on efficiency. Most the enzymes work fine in the 5 to 6 range. Maybe it would be more of an issue if brewing dark beers with RO water or really light beers with high alkaline water.

 

[doug293cz]

water to grist ratio X temperature X mash pH X time = mash efficiency. Go back over the formula; something is out of kilter. As far as the grist, it was always touted that the crush should reduce the average grain kernel to about 5 pieces. These days too many want to reduce the grain bill to powder. Everyone seems to want to look for their lost keys under the street light instead of where they dropped them.

I didn't offer that as a real mathematical formula. These are the components of a mash. Each has a major effect on the overall performance of the mashing. If you focus on what's important, many of your problems tend to vanish.

Yeah the formula is utter gibberish. There are real formulas for efficiency:

Conversion Efficiency = Wt of Extract Created in Mash / Wt of Potential Extract in Grain​

Lauter Efficiency = Wt of Extract Collected in BK / Wt of Extract Created in Mash​

Mash Efficiency = Wt of Extract Collected in BK / Wt of Potential Extract in Grain​

Mash Efficiency = Conversion Efficiency * Lauter Efficiency (algebra from 1st 3 formulas)​

Brewhouse Efficiency = Wt of Extract Collected in Fermenter / Wt of Potential Extract in Grain​

Packaged Efficiency (or End-to-End Efficiency) = Wt of Extract in Packaged Beer / Wt of Potential Extract in Grain​

​

Extract is all the dissolved components in the wort. Extract is about 90% sugars and dextrins, with the balance being mostly protein, and some other minor components.

Conversion of starch to sugar and dextrins is a two step process: gelatinization followed by hydrolysis. Hydrolysis is the breaking down of the long starch chains into dextrins and sugars. Hydrolysis is catalyzed by the enzymes (alpha and beta amylase, and limit dextrinase.) Gelatinization must occur before hydrolysis can occur, because hydrolysis requires that the end of the chain being hydrolyzed be surrounded by water (each bond broken requires one water molecule to react with the bond in order to break it.) Hydrolysis also requires an enzyme molecule to be in contact with the bond being broken, and since the enzymes are large protein molecules, they cannot penetrate into the dense un-gelatinized starch granule structure.

Gelatinization is slower than hydrolysis, and must happen first, so it is the step that controls the overall rate of conversion (i.e. the rate controlling step.) Rate of conversion is controlled by the rate of gelatinization.

Gelatinization starts at the surface of the grits and proceeds inward. The larger the grit, the longer it takes to fully gelatinize the grit. This is the reason that crush fineness is the most important factor in determining the time to complete gelatinization, and thus the time to complete conversion.

The rate of gelatinization is also temperature dependent - it occurs faster at higher temperatures. The rate of gelatinization at a particular temperature is affected by the internal structure of the starch granules. So, some starch granules require higher temps to gelatinize at a given rate than other starch granules. Since gelatinization is faster at higher temperatures, conversion is faster at higher temperatures.

So, smaller grits and higher temperatures lead to faster gelatinization completion, and thus faster conversion completion. There is a limit on raising the temperature to reduce the mash time because as the temps get higher the rates of enzyme denaturing also increase, and at high enough temperatures the enzymes denature faster than gelatinization can complete, and conversion stops.

Mash thickness has a small effect on rate of conversion, and thus required mash time for complete conversion. Kai Troester has shown that thinner mashes convert slightly faster than thick mashes (more strike water is better.)

pH affects primarily the rate at which the enzymes cause hydrolysis, so as long as the pH is in a range that hydrolysis occurs faster than gelatinization, it doesn't really affect conversion efficiency. As state in a post above range is about 5.0 to 6.0 (5.2 to 5.8 would be a more conservative range.)

Edit: We do have a data point now that demonstrates that in cases of excessively low pH, enzyme action (but not gelatinization) will be shut down almost completely. Unfortunately, there were no pH readings taken of the mash.

The net is that the time to get to 100% conversion is an interaction between gist size, mash temp, and mash time. No one has come up with a formula that predicts this (AFAIK.) It is possible to measure the percent conversion by measuring the SG of the wort in the mash. Turns out the SG at 100% conversion is a function of only grain bill weight, grain bill weighted potential, and strike water volume. So, to get complete conversion you can just mash until the SG in the mash is equal to the max possible SG (spreadsheet attached below.) You can approximate conversion efficiency by using either of the formulas below (the rigorous formula is a little more complicated, but the errors of the simplified formula are small when you are close to 100% conversion):

Conversion Efficiency = Measured °Plato / Max °Plato​

Conversion Efficiency = (Measured SG - 1) / (Max SG -1)​

​

Lauter efficiency depends on the sparge process used. It's possible to accurately predict lauter efficiency for batch and no sparge (as long as the wort in the mash is thoroughly mixed prior to run off.) With batch sparging more sparge steps give higher efficiency, but each additional step provides a smaller increment of improvement vs. the previous sparge step (assuming a constant pre-boil volume - same amount of total brewing water.) Fly sparging, if done well, can give a slightly higher lauter efficiency than a triple batch sparge, but it is possible to get lower lauter efficiency if you have channeling during fly sparging. Accurately predicting fly sparge lauter efficiency requires solving differential equations whose parameters depend heavily on the specific equipment and process details, so hasn't been done for a homebrew situation (AFAIK.) Lauter efficiency for all methods decreases with increasing grain bill weight for a given pre-boil volume. Increasing pre-boil volume will compensate for larger grain bills, but then you have to boil off more water to reach a specific post-boil volume target.

As stated above the difference between mash efficiency and brewhouse efficiency is all about volume left behind in the BK and any plumbing.



Brew on

 

[micraftbeer]

Basically, my problem in the last brew was low mash conversion, which is what I believe led to my Brewhouse Efficiency of 48%.

Early in my all-grain days, I didn't realize the difference between what BeerSmith displayed in large font, "Brewhouse Efficiency", and the fact that most people in the forums talk "Efficiency" and mean "Mash Efficiency". So can you define how you're calculating your Brewhouse Efficiency?

Also, aside from fancy gauges, you can make big effects if your estimates of volumes are off.

 

[CascadesBrewer]

@doug293cz: Really well written. I learned a few things about mashing.

most people in the forums talk "Efficiency" and mean "Mash Efficiency"

I find there is a mix of what people define as "Efficiency". It probably depends a bit on what software you are used to using. I use BeerSmith (or similar software in the past) and I tune my recipes around gravity and volume into the fermenter. There are weaknesses to this approach, but I am generally able to hit my volume and gravity in the fermenter and volume into a keg.

I probably should do a better job of adjusting my profiles for heavily hopped beers. I usually try to take a swag for losses to hops in the kettle and dry hop, but I often end up not filling a keg all the way.

 

[doug293cz]

@doug293cz: Really well written. I learned a few things about mashing.

Thanks.

Brew on

 

[DuncB]

@doug293cz

Thanks for all that info. I reckon my mash lauters far too quickly, I use a guten electric one vessel, I am crushing my own grain with a maltzilla. This really does seem to crush the grain rather than any chopping up and I get lots of whole husks with the crushed grain inside and some flour. Almost as if I've added loads of rice hulls.
Recirculation and lautering is fast and I often struggle to keep the malt bill covered unless using some sticky adjuncts, the pump is running full speed recirculating. I do have Careful temp and pH control and salts.
I have progressively tightened the mill gap now using 0.5mm which is small almost in an attempt to get a stuck mash but can't seem to achieve this. Reasoning is that when I come to sparge I lift the grain basket and the wort pours down, sparging with me sprinkling from the sparge tank is all done in about 10 minutes and the grain bed can't be kept covered.
No obvious channelling and using the correct volumes of liquid I think but the runnings that come out when I lift the malt pipe over a bucket after the sparge are still around 1030 and the grains taste sweet.
I'm definitely leaving a lot of sugar behind but can't work out how to get it out without using loads of sparge water and then would need a really long boil.
Brewhouse efficiency is 72 to 76 percent but I'm sure could be better, given my findings of the bucket sparge runoff.

Any ideas how to slow this all down?

 

[doug293cz]

@doug293cz

Thanks for all that info. I reckon my mash lauters far too quickly, I use a guten electric one vessel, I am crushing my own grain with a maltzilla. This really does seem to crush the grain rather than any chopping up and I get lots of whole husks with the crushed grain inside and some flour. Almost as if I've added loads of rice hulls.
Recirculation and lautering is fast and I often struggle to keep the malt bill covered unless using some sticky adjuncts, the pump is running full speed recirculating. I do have Careful temp and pH control and salts.
I have progressively tightened the mill gap now using 0.5mm which is small almost in an attempt to get a stuck mash but can't seem to achieve this. Reasoning is that when I come to sparge I lift the grain basket and the wort pours down, sparging with me sprinkling from the sparge tank is all done in about 10 minutes and the grain bed can't be kept covered.
No obvious channelling and using the correct volumes of liquid I think but the runnings that come out when I lift the malt pipe over a bucket after the sparge are still around 1030 and the grains taste sweet.
I'm definitely leaving a lot of sugar behind but can't work out how to get it out without using loads of sparge water and then would need a really long boil.
Brewhouse efficiency is 72 to 76 percent but I'm sure could be better, given my findings of the bucket sparge runoff.

Any ideas how to slow this all down?

Can you post a pic of your grain basket? Also what are the diameters of your BK and basket?

Brew on

 

[bracconiere]

I mashed in at 152 F,

seems low temp? you want to HIT 152 not mash in at it?

 

[micraftbeer]

@DuncB , sounds like you've worked your grain crush to the point you'd want- just shy of stuck mash. If you're worried about doing a sparge taking longer to boil, if you have another pot you could put on your stove and heat the water to like 168F, that would be a typical mash out temperature. Depending on your space and options that might be more of a pain than it's worth, but I've found a single sparge (not full volume mash) is a significant boost in conversion efficiency.

I'm sure I've done conversion efficiency experiments on the Mash & Boil in the past trying to characterize the effect of sparge, but can't seem to find it. I did however find my experiment on the Anvil Foundry, which is the same type of system. For my experiment I used grain all from the same 55lb sack, then mashed at common temperature/time with same additives, but varied the mash process. First was full-volume mash, next was full-volume mash but recirculating throughout mash with a pump, and last was mashing at a loose 2.4 qt/lb, followed by pouring 1.5 gallons of sparge water through the basket (Anvil 6.5, making a 3.5 gallon batch). The results were striking: 1) Full volume 72% mash efficiency, 2) Full volume + recirc 74%, 3) Recirc + single sparge 87% mash efficiency.

So if you can find a way to get some hot water (but not too hot) to do a sparge, you might get some good improvement.

 

[DuncB]

Can you post a pic of your grain basket? Also what are the diameters of your BK and basket?

Brew on

Malt pipe Diameter 33cm and depth is 50 cm is resting 15mm below the kettle rim.

Kettle diameter 38 cm and depth is 65cm

Overall height 85cm
Grain post crush
During mash, I know it looks uncrushed but assure you it is.

Also further images here showing malt pipe lifted, it can be lifted in stages which is what I do. https://www.keg-king.com.au/keg-king-guten-70l-brewery-system.html

I haven't been using it full but aiming for 30 litre into fermenter. So the grain bill isn't half filling the malt pipe.

Last brew English Ale
Mash 19litre, sparge 17 litre, pH 5.3 Hops 200 g pellets in total.
Grains 4.9 kg 2 row, 0.223 kg each of amber, med crystal and wheat malt.


OG temp adjusted 1.040 and fermenter volume 30.5

 

[doug293cz]

@DuncB , sounds like you've worked your grain crush to the point you'd want- just shy of stuck mash. If you're worried about doing a sparge taking longer to boil, if you have another pot you could put on your stove and heat the water to like 168F, that would be a typical mash out temperature. Depending on your space and options that might be more of a pain than it's worth, but I've found a single sparge (not full volume mash) is a significant boost in conversion efficiency.

I'm sure I've done conversion efficiency experiments on the Mash & Boil in the past trying to characterize the effect of sparge, but can't seem to find it. I did however find my experiment on the Anvil Foundry, which is the same type of system. For my experiment I used grain all from the same 55lb sack, then mashed at common temperature/time with same additives, but varied the mash process. First was full-volume mash, next was full-volume mash but recirculating throughout mash with a pump, and last was mashing at a loose 2.4 qt/lb, followed by pouring 1.5 gallons of sparge water through the basket (Anvil 6.5, making a 3.5 gallon batch). The results were striking: 1) Full volume 72% mash efficiency, 2) Full volume + recirc 74%, 3) Recirc + single sparge 87% mash efficiency.

So if you can find a way to get some hot water (but not too hot) to do a sparge, you might get some good improvement.

You don't need hot water to sparge. Sparging with hot water will reduce the time to boil, but if you don't have a way to heat the sparge water, don't worry about it.

Sparging has no effect on conversion efficiency* - it affects lauter efficiency, and can give you an 8% to 15% improvement in lauter efficiency. Mash efficiency equals conversion efficiency times lauter efficiency.

*Sparge temp may affect conversion if your conversion is not complete at the end of the mash. But, you are better off extending your mash to complete the conversion, rather than depending on the sparge to do it.

Brew on

 

[DuncB]

@DuncB , sounds like you've worked your grain crush to the point you'd want- just shy of stuck mash. If you're worried about doing a sparge taking longer to boil, if you have another pot you could put on your stove and heat the water to like 168F, that would be a typical mash out temperature. Depending on your space and options that might be more of a pain than it's worth, but I've found a single sparge (not full volume mash) is a significant boost in conversion efficiency.

I'm sure I've done conversion efficiency experiments on the Mash & Boil in the past trying to characterize the effect of sparge, but can't seem to find it. I did however find my experiment on the Anvil Foundry, which is the same type of system. For my experiment I used grain all from the same 55lb sack, then mashed at common temperature/time with same additives, but varied the mash process. First was full-volume mash, next was full-volume mash but recirculating throughout mash with a pump, and last was mashing at a loose 2.4 qt/lb, followed by pouring 1.5 gallons of sparge water through the basket (Anvil 6.5, making a 3.5 gallon batch). The results were striking: 1) Full volume 72% mash efficiency, 2) Full volume + recirc 74%, 3) Recirc + single sparge 87% mash efficiency.

So if you can find a way to get some hot water (but not too hot) to do a sparge, you might get some good improvement.

Thank you,
More info since your post.
forgot to mention have been mashing out as well, have always sparged with water at mash out temp ( i set the sparge water so that it is at the mash out temp when it hits the grain bed not in the heater ).
I haven't been able to get a stuck mash yet although near with a fitbits clone grain bill was 1.8kg ale malt, 0.55 sour grapes, 0.55 gladiator, 0.55 wheat malt, 0.55 flaked oats. Wheat malt milled separately but still at 0.5, did need rice hulls and glucanase, ( this beer uses alpha amylase as well it's a low cal )
Rest of grain was 2/3 at 0.5mm and 1/3 at 0.75mm, difficult / slow sparge but BHE was 83 %.

 

[DuncB]

You don't need hot water to sparge. Sparging with hot water will reduce the time to boil, but if you don't have a way to heat the sparge water, don't worry about it.


Brew on

I have a separate water heater so hot sparge no problem, I start the elements towards boil temp at the end of mash out ( 3000w element) so not had any delays getting to the boil.

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.

 

[doug293cz]

View attachment 733913Malt pipe Diameter 33cm and depth is 50 cm is resting 15mm below the kettle rim.

View attachment 733910Kettle diameter 38 cm and depth is 65cm

View attachment 733907Overall height 85cm
View attachment 733905Grain post crush
View attachment 733906During mash, I know it looks uncrushed but assure you it is.

Also further images here showing malt pipe lifted, it can be lifted in stages which is what I do. https://www.keg-king.com.au/keg-king-guten-70l-brewery-system.html

I haven't been using it full but aiming for 30 litre into fermenter. So the grain bill isn't half filling the malt pipe.

Last brew English Ale
Mash 19litre, sparge 17 litre, pH 5.3 Hops 200 g pellets in total.
Grains 4.9 kg 2 row, 0.223 kg each of amber, med crystal and wheat malt.


OG temp adjusted 1.040 and fermenter volume 30.5
View attachment 733912

From the linked pics, it looks like the basket is solid sided, which makes it a malt pipe. In a malt pipe system, the wort outside of the pipe does not participate in the mash and isn't recirculated to any significant extent. This means the wort between the BK wall and the pipe is at lower SG than the wort in the pipe and under it. You really want to homogenize all the wort as best you can prior to starting your sparge (the less sugar in the pipe prior to the sparge, the less sugar left in the grain in the in the pipe after the sparge.) The best way to homogenize with a malt pipe system is to lift the pipe, let it drain completely, re-immerse the the pipe, and repeat multiple times. Stirring the mash in the pipe is not effective for homogenization.

For pour over sparging in this kind of system, you want to distribute the sparge water as uniformly over the exposed surface of the mash as possible. A fine mist sprayer is better than a sprinkler head watering can.

At 0.5 mm (0.020") gap, your grain is well crushed, so that is not an issue.

Brew on

 

[DuncB]

@doug293cz
Yes malt pipe is solid sided, but I recirculate throughout the mash with the pump, so isn't the wort at the side getting circulated?
The pump inlet is in the base of the kettle and usually about 6-14 litres on the gauge during mash ( depending on how fast the pump runs).
The mash normally has a screen on the grains so that the recirc wort doesn't just jet straight onto the grain.
Does it matter during sparging if I'm just sparging onto grains not liquid on the grains?

 

[micraftbeer]

I wasn't suggesting the temp for sparge due to an efficiency effect, I thought he was concerned that sparging would end up taking him longer to get to a boil after. Maybe I misunderstood that.

I'll add that in my mash efficiency experiment I referenced above, my sparge was just pouring water on top of the malt in the pipe as it sat on its stops. Nothing fancy or timed out to be slow or anything like that.

 

[doug293cz]

@doug293cz
Yes malt pipe is solid sided, but I recirculate throughout the mash with the pump, so isn't the wort at the side getting circulated?
The pump inlet is in the base of the kettle and usually about 6-14 litres on the gauge during mash ( depending on how fast the pump runs).
The mash normally has a screen on the grains so that the recirc wort doesn't just jet straight onto the grain.
Does it matter during sparging if I'm just sparging onto grains not liquid on the grains?

No, the wort between the pipe and the BK walls does not participate in the recirculation to any significant extent, unless some of the return wort is split to flow into the gap. Here's something to try: at the end of the mash measure the SG of the wort in the pipe, and the wort in the gap.

When sparging on to grains (without a liquid layer on top) you need to work very hard to get the sparge water evenly distributed across the top of the exposed grain. A fine droplet sprayer, moved back and forth over the surface is probably the best you can do.

Brew on

 

[DuncB]

I wasn't suggesting the temp for sparge due to an efficiency effect, I thought he was concerned that sparging would end up taking him longer to get to a boil after. Maybe I misunderstood that.

I'll add that in my mash efficiency experiment I referenced above, my sparge was just pouring water on top of the malt in the pipe as it sat on its stops. Nothing fancy or timed out to be slow or anything like that.

So you lifted malt pipe and then sparged? if I'm understanding correctly not sparged with it resting on the top stop in the wort.

No I'm not worried about the time except that the sparge is really quick and hence perhaps less efficient at extracting the sugars.

 

[DuncB]

No, the wort between the pipe and the BK walls does not participate in the recirculation to any significant extent, unless some of the return wort is split to flow into the gap. Here's something to try: at the end of the mash measure the SG of the wort in the pipe, and the wort in the gap.

When sparging on to grains (without a liquid layer on top) you need to work very hard to get the sparge water evenly distributed across the top of the exposed grain. A fine droplet sprayer, moved back and forth over the surface is probably the best you can do.

Brew on

I'm up for the challenge of assessing the return and gap wort gravities.
I think i need a rotating sprinkler arm for the sparge, will get designing so that it rests on the overflow pipe, dish washer destruction perhaps.

 

[micraftbeer]

So you lifted malt pipe and then sparged? if I'm understanding correctly not sparged with it resting on the top stop in the wort.

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.

 

[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: