Unpredictable efficiency on all-in-one system

[dannythemanny]

Hi all,

I used to brew with separate vessels - a HLT, mash tun and separate kettle. I would batch sparge and achieve around 80% efficiency fairly consistently.

In the interests of space, I moved to an all-in-one system - a Klarstein Brauheld Pro. I have been having wildy varying efficiency with it, which is incredibly frustrating. When I brew smaller grain bills, I get pretty decent efficiency - high 70s. A little over 4kg, and it drops to low 70s. Today, I brewed with 6.5kg and if my calculations are correct, I got a measly 45%.

I wouldn't mind having a low efficiency system if only it was consistent. As it is, I would have achieved the same OG today had I used 4kg instead of 6.5kg!

In determining my water calculations, I tend to try to make the mash thin so that the ratio *inside* the grain basket is as close to 3.2L/kg as I can get (or higher if I can). My reasoning for this is that when I brew smaller beers, I get decent efficiency with this approach - eg. 4.1kg of grain with 28L of strike water gives a ratio of 6.8L/kg, or 4.15L/kg inside the grain basket (if my dodgy maths are correct), 3.45kg of grain with 24L of strike water gives a ratio of 7.05L/kg, or 4.12L/kg inside the grain basket (again, if my dodgy maths are correct). I sparge to top up to 30L so that I end up with 25L in the kettle post-boil.

When I've tried a bit more grain, here is an example of what I get: 5.3kg of grain with 27L of strike water gives a ratio (total/inside grain basket) or 5.14/3.09 L/kg and efficiency of only 65%. Thinking I was maybe under-sparging in favour of a thinner mash, I thought I'd try a thicker mash that would allow me to have more room to sparge: 7.25kg of grain with 23L of strike water giving a mash ratio of 3.14/1.8 L/kg. This brought efficiency down to 53%, so I thought I'd try the opposite today and tried to mash 6.5kg of grain with as much strike water as I could fit - 28.5L, giving a ratio of 4.43/2.7 L/kg (outside/inside). I make this 45% efficiency!

It's pretty maddening to think that I got an OG of 1.049 from 4.3kg of pilsner malt and carapils and today only 1.041 from 6.5kg of the exact same grain! These two grain bills are very similar: the first is a 98/2% ratio and the other 96/4% and I did a simple mash of 40C - 60C - 70C (30 mins at each) in both cases.

I'm pretty bummed out about this because I don't know what the culprit is. I suppose the system simply isn't large enough to reliably brew anything above 5-ish%, which seems a shame. But I think I might be missing something... I do buy grain pre-crushed, so maybe I should buy a mill and go from there...? But these discrepancies are present between the different grain bills using grain from the same bag, so maybe not. Maybe I need to be a lot more precise with dialling in the water for this system, but having tried both extremes and not seeing a lot of difference with either, I doubt that's the issue either, tbh.

Anyone else had this kind of issue with one of these systems, and did you find a workaround? I've seen the "double mash" idea of mashing the grain in stages (eg. for a grain bill of 8kg, mash 4kg, remove it, and mash the other 4kg in the wort from the first mash). This strikes me as a bit of a pain because I'd be looking at an extra hour minimum on brew day. I was wondering if there might be some way of batch sparging when I'm aiming for OG over 1.045..? I can't figure it out if there is, though!

 

[foxy]

A larger grain bill will give a lower mash efficiency. Are you using any program like Brewers Friend?

 

[dannythemanny]

A larger grain bill will give a lower mash efficiency. Are you using any program like Brewers Friend?

I'm not, no. Just my own spreadsheet that I've kind of added to over the years! That is quite some drop in efficiency,, though, right?

 

[dannythemanny]

One thing I haven't considered is that I recently have found it much easier when using the all-in-one system to pour the grain into the basket and then lower that into the strike water. It's just easier in terms of dust off the grain. Could it be possible that when I do this with lower OG brews, where I have a much higher ratio of strike water (say, 4L/kg), this doesn't cause an issue beause it's such a thin mash, but when I do it with larger grain bills, I'm getting dough balls? I really doubt this, because I still give it a good stir when I dough-in. I suppose it couldn't hurt to try going back to adding the grain a few hundred grams at a time, though.

 

[hop-a-long]

I've learnt in the past few years that, if I want to do a bigger grainbill, it's better to do a reitterated mash. You'll get better results on efficiëncy.

 

[Moe]

I have had similar issues with larger grain bills on my Brewzilla.

Unfortunately I don’t have any answers but I’m interested to hear if anyone has any ideas.

 

[starseeker]

Are you stirring the grains a few times through the mash ?

 

[dannythemanny]

I think the thing that is bothering me is that it seems I won't be able to get above 5% ABV with the volumes I shoot for (and that's if I'm lucky!) I had another thought, similar to the reiterated mash - I could try "batch sparging" with my HLT. I have a false bottom for it. So I could mash in at, say, 2L/kg if that's not too ridiculously thick, and then at the end of the mash, transfer the grain into the sparge water in the HLT, giving it a good stir and draining it..? If the first mash would be thick, though, the HLT mash would be even thicker! Might make it impractical...

Maybe the reiterated mash may be the way to go. If I do that, are there guidelines about how to split the grain bill? From what I've seen, it looks like you only sparge the first mash, not the second. My instinct would be to sparge the second, since the wort is already parially saturated with sugar when that one is added... But I assume I'm wrong about that!

Cheers.

 

[dannythemanny]

Are you stirring the grains a few times through the mash ?

No, I'm not, actually. But I never have done, really. Can't hurt, though, I guess.

 

[RoomWithABrew]

No, I'm not, actually. But I never have done, really. Can't hurt, though, I guess.

I started with a Robobrew 3.0 and had similar issues. There's definitely a sweet spot.
I did aim for around 3 litres / kg sometimes a bit more and efficiency around 74%. Grain crush and flow seems important, I find that a shot of glucanase does help unsticking the mash, doesn't take up any volume like rice hulls do. I did use to stir a few times and also recirculate, adjusting the flow thru the mash as it progressed. I could only really make small volume big beers such as barley wine, had hopeless figures if I tried to get bigger volumes with bigger grain bills.
I always felt the problem was extraction of the sugars rather than the enzyme efficiency and felt I needed much more sparge but there wasn't the capacity for this.
@schmurf has had a great increase ( unplanned ) with an overnight mash so maybe that's worth looking at with a stiffer mash and then you'd have more to sparge with.
Assume you are hitting your water and pH targets.
I upgraded to a Guten 70 litre because of these issues, not really wanting to make 55 litre + batches but can make a big beer without hassle, bigger vessel also means no boilover worries and it does have a little better control 100w increments. Paradoxically I find it difficult to keep the mash floating as it runs through so well and I'm still fiddling with crush sizes to see how this changes things. The grain bed with 7kg is much thinner as the malt pipe is nearly 40 cm across.

 

[foxy]

While conversion is the same, extraction isn't. The more grain you have the more difficult the extraction. Getting consistency is getting the balance right, easier for me as I no sparge. depending on the grain bill my strike water volume is usually between 32 and 34 litres in a 40 litre Guten, using brewers friend I can get the figures pretty much spot on. To get better extraction I put my grain basket over a bowl use a 20 litre pale with about 15 litres of water in it. Place the pale over the grain and let it press the wort from the grain.

 

[dannythemanny]

I started with a Robobrew 3.0 and had similar issues. There's definitely a sweet spot.
I did aim for around 3 litres / kg sometimes a bit more and efficiency around 74%. Grain crush and flow seems important, I find that a shot of glucanase does help unsticking the mash, doesn't take up any volume like rice hulls do. I did use to stir a few times and also recirculate, adjusting the flow thru the mash as it progressed. I could only really make small volume big beers such as barley wine, had hopeless figures if I tried to get bigger volumes with bigger grain bills.
I always felt the problem was extraction of the sugars rather than the enzyme efficiency and felt I needed much more sparge but there wasn't the capacity for this.
@schmurf has had a great increase ( unplanned ) with an overnight mash so maybe that's worth looking at with a stiffer mash and then you'd have more to sparge with.
Assume you are hitting your water and pH targets.
I upgraded to a Guten 70 litre because of these issues, not really wanting to make 55 litre + batches but can make a big beer without hassle, bigger vessel also means no boilover worries and it does have a little better control 100w increments. Paradoxically I find it difficult to keep the mash floating as it runs through so well and I'm still fiddling with crush sizes to see how this changes things. The grain bed with 7kg is much thinner as the malt pipe is nearly 40 cm across.

Thanks, this is great info. I'm wondering whether it's wort investing in a mill just to be able to eliminate crush as a factor, if nothing else...

 

[dannythemanny]

While conversion is the same, extraction isn't. The more grain you have the more difficult the extraction. Getting consistency is getting the balance right, easier for me as I no sparge. depending on the grain bill my strike water volume is usually between 32 and 34 litres in a 40 litre Guten, using brewers friend I can get the figures pretty much spot on. To get better extraction I put my grain basket over a bowl use a 20 litre pale with about 15 litres of water in it. Place the pale over the grain and let it press the wort from the grain.

Interesting. I press down on the sparge plate before and after sparging to try and squeeze it all out. What is your typical batch size?

 

[dannythemanny]

I started with a Robobrew 3.0 and had similar issues. There's definitely a sweet spot.
I did aim for around 3 litres / kg sometimes a bit more and efficiency around 74%. Grain crush and flow seems important, I find that a shot of glucanase does help unsticking the mash, doesn't take up any volume like rice hulls do. I did use to stir a few times and also recirculate, adjusting the flow thru the mash as it progressed. I could only really make small volume big beers such as barley wine, had hopeless figures if I tried to get bigger volumes with bigger grain bills.
I always felt the problem was extraction of the sugars rather than the enzyme efficiency and felt I needed much more sparge but there wasn't the capacity for this.
@schmurf has had a great increase ( unplanned ) with an overnight mash so maybe that's worth looking at with a stiffer mash and then you'd have more to sparge with.
Assume you are hitting your water and pH targets.
I upgraded to a Guten 70 litre because of these issues, not really wanting to make 55 litre + batches but can make a big beer without hassle, bigger vessel also means no boilover worries and it does have a little better control 100w increments. Paradoxically I find it difficult to keep the mash floating as it runs through so well and I'm still fiddling with crush sizes to see how this changes things. The grain bed with 7kg is much thinner as the malt pipe is nearly 40 cm across.

When you say 3L/kg, I'm assuming that's just the total amount of strike water, not the liquor: grist ratio inside the malt pipe?

 

[foxy]

Thanks, this is great info. I'm wondering whether it's wort investing in a mill just to be able to eliminate crush as a factor, if nothing else...

I mill my own grain, and it can make some difference not a lot. Check the grain from your supplier who is milling it, it should just be cracked with the husk intact. Also don't worry to much about efficiency figures, I have said it more than once the efficiency percentage isn't what you are shooting for, its a constant result using your method on your equipment.

Interesting. I press down on the sparge plate before and after sparging to try and squeeze it all out. What is your typical batch size?

Depends on the OG I am after, 19 to 21 litres I can get another couple of litres by pouring 5 litres of trub left in the kettle into a 5 litre jug and putting it in the fridge for a while. Let it settle and can get 2 more litres and pour the trub and hop debris away. Sometimes that is included in my total sometime I keep it for starters.

 

[dannythemanny]

I mill my own grain, and it can make some difference not a lot. Check the grain from your supplier who is milling it, it should just be cracked with the husk intact. Also don't worry to much about efficiency figures, I have said it more than once the efficiency percentage isn't what you are shooting for, its a constant result using your method on your equipment.


Depends on the OG I am after, 19 to 21 litres I can get another couple of litres by pouring 5 litres of trub left in the kettle into a 5 litre jug and putting it in the fridge for a while. Let it settle and can get 2 more litres and pour the trub and hop debris away. Sometimes that is included in my total sometime I keep it for starters.

Yeah, I think the easiest thing to do is accept that if I'm brewing anything higher than 1.048, then I need to cut the post boil volume by a litre or two.

 

[dannythemanny]

Or.... How about this?

Let's say I have 6.5kg grain bill and want to collect 22L in the FV. I could mash 2kg in my HLT with false bottom using approx 6L liquor. In my kettle, I would *simultaneously* mash the remaining 4.5kg in about 14L. I could then reunite the grains in the malt pipe, and would have 10L to sparge with. Only issue is, while my HLT has a false bottom, it doesn't have a pump, so may not get great extraction, but surely better than what I've got now, I would think.

 

[trueblue]

My own experience is before I bought my grainfather I would normally get an efficiency around 70-75%. Since I bought it it is now 75-80% regardless of gravity. I mill my own grains.

 

[foxy]

Or.... How about this?

Let's say I have 6.5kg grain bill and want to collect 22L in the FV. I could mash 2kg in my HLT with false bottom using approx 6L liquor. In my kettle, I would *simultaneously* mash the remaining 4.5kg in about 14L. I could then reunite the grains in the malt pipe, and would have 10L to sparge with. Only issue is, while my HLT has a false bottom, it doesn't have a pump, so may not get great extraction, but surely better than what I've got now, I would think.

I don't know what your capacity is on your m/c but if you want quality try a no sparge, 6,5 kg I can mash into 32 litres strike water, but I set my efficiency at 55% so you can work it out I am only going to get slightly over a 5% ABV beer could go 5.5%. Cutting out the sparge gives a cleaner better tasting beer.

 

[RoomWithABrew]

When you say 3L/kg, I'm assuming that's just the total amount of strike water, not the liquor: grist ratio inside the malt pipe?

Yes the amount in the Robobrew at the start of dough in.
I do as above also give the grains a good squeeze, not had any tannin problems.