Batch Sparge/Efficiency Analysis - Kai Troester's work

[Adr_0]

Hi all,

I'm sure you've seen Braukaiser and some of the great analysis and tools available on this site.

My 25L mash tun has been too small for bigger batches (1070+) and I was looking at upgrading to a larger 33L esky, with less insulation as I no longer need it since going RIMS.

I was curious about efficiency, volumes and liquor/grain ratio and getting a feel for the maximum grain size I could do, so went through a bit of Kai's site.

Long story short, I added a 'general' equation that can be used for specific grain sizes and different first runnings and sparge volumes:

Basically:
-VR is the volume of the runnings (first, sparge1, sparge2)
-VDG is the volume held up in the grain, which is directly proportional to the weight of grain
-VLT is the volume of liquid in the mash tun prior to drawing off each running (first, sparge1, sparge2)
-E is the extract potential of the grains, typically around 80%

This also considers liquid swelling due to the addition of sugar. So I put together a spreadsheet that looks a bit like this:


And can plot out expected efficiencies, see at which point the grain becomes too much, liquor/grain ratios and where there is too much sparge water etc.


Kai's site is great and it's been good to be able to get my own model to look at how to best use the system with a larger mash tun, so that some of the bigger recipes are closer to the mark rather than just guessing.

 

[2cranky]

Umm…I know my daughter would understand this but she is too young to brew.
What does all that mean to a poor uneducated fool?

 

[Adr_0]

Umm…I know my daughter would understand this but she is too young to brew.
What does all that mean to a poor uneducated fool?

Don't ask me!

 

[MHB]

I would be very careful using 80% for E, that might be what the FGD yield is (Fine Grind Dry - basically flour), but we are working with CGAI (Coarse Grind As Is) so you need to allow for moisture (~4% is typical) and the C/F (Coarse/Fine) difference (~1-1.5%), those are for a premium quality Pale Malt.
75% would be a lot closer to the money.

There is another form of the same equation that I find handy, it is usually used to predict the gravity in Plato (oP)
First Runnings oP = Potential Yield (E)/(L:G +E). For a pale malt bill with a potential of 75% and a L:G of 4:1
oP (First Runnings)= 0.75/(4+0.74) = 0.75/4.75 = 0.15789 call it 15.8oP or 1.063.

You could calculate the mass of extract in the first runnings, then use the remaining potential and the amount of sparge water added to calculate the oP of the second runnings.
Time is very important, second runnings could take 1/2 an hour or more to reach equilibrium - remembering that the first runnings have had an hour or so to equilibrate, second runnings wont take as long but it wont happen instantly either.

Fun bit of thinking
Mark

 

[Danscraftbeer]

hehe yeah I actually skip all that technical maths and still hit my targets bang on. :blink:
The relation between final run off gravity and total brew house efficiency is the key in my little brewery.

Maybe off topic: Actually I was worried about getting too high total efficiency. Worried about over sparging and getting Tannin, Astringency. Lower ABV beers I have sparged until the gravity is as low as 1.006. Total effiency up to 85%. I think that is pushing it. Sparge until gravity is 1.010 is acceptable and gets great efficiency. 72-80%
I've done the testing of less sparging (lower efficiency. final run off like 1.030 BHE = ~70%) wondering if you get better flavour but I don't think its the case.
No detectable Tannins or off flavour that I can detect when final sparge run off grav = 1.010.
+ longer boils to reduce the volume etc.
$0.02

 

[MHB]

Dans...
You have been jumping into a few threads with your Its too hard or It doesn't matter, but really being able to take accurate readings at any point in the brew is a pretty basic skill, it can be very important if you are trying to understand what is really going inside your brew.
Sure overall efficiency is also important but it is made up of lots of parts, if you understand the components and can monitor them, you wont be worried about over sparging, or even getting too high an efficiency.
If you aren't hitting your expected markers, you will be able to tell why not and fix any problems that come up.
Mark

 

[Danscraftbeer]

Dans...
You have been jumping into a few threads with your Its too hard or It doesn't matter, but really being able to take accurate readings at any point in the brew is a pretty basic skill, it can be very important if you are trying to understand what is really going inside your brew.
Sure overall efficiency is also important but it is made up of lots of parts, if you understand the components and can monitor them, you wont be worried about over sparging, or even getting too high an efficiency.
If you aren't hitting your expected markers, you will be able to tell why not and fix any problems that come up.
Mark

Agreed. I didn't mean to give that impression that it doesn't matter or its too hard. I should mention that I used to measure every little part, every run off etc. Its all learning and any comments I made was relevant to my findings. Do the hard, technical. fiddly stuff to find your comfort zone I guess. Eg. don't be surprized if you find you don't need to continue to do all that technical stuff to get consistent results.

 

[MHB]

Unless for example - you were thinking of upsizing your equipment and wanted to get some idea of how it will preform... which is the point of the exercise in this thread.
M

 

[Adr_0]

Umm…I know my daughter would understand this but she is too young to brew.
What does all that mean to a poor uneducated fool?

Yeah there are a few things:
- The reason you lose lautering efficiency as you go higher in grain weight is that more wort gets retained in the grain
- Stiff mashes, considering the runoff volume is low in proportion to the retained wort volume in the grain, will get a much lower lautering efficiency for the first runnings
- Even though sparging may be diluted, there is less sugar available in each consequent sparge, so you don't necessarily get much out of that

I always thought "the more sparges, the closer to fly sparging" and could generally not fit a lot into my small mash tun, so I'd split it over two sparges. The mash water/grain ratio may have been ok, but would have been getting only miniscule amounts from my sparges as there was so little runoff each time.

I did a quick comparison with 5.5kg of grain:
- 15L strike, 2 x 9-10L sparges (equal runoff volume and sparge volume) got me 81% theoretical and 55% in the first runnings
- 20L strike with 1 x 14-15L sparge got me 89% with 66% in the first runnings
...so basically that time, handling, etc for the second sparge would have put me behind

I would be very careful using 80% for E, that might be what the FGD yield is (Fine Grind Dry - basically flour), but we are working with CGAI (Coarse Grind As Is) so you need to allow for moisture (~4% is typical) and the C/F (Coarse/Fine) difference (~1-1.5%), those are for a premium quality Pale Malt.
75% would be a lot closer to the money.

There is another form of the same equation that I find handy, it is usually used to predict the gravity in Plato (oP)
First Runnings oP = Potential Yield (E)/(L:G +E). For a pale malt bill with a potential of 75% and a L:G of 4:1
oP (First Runnings)= 0.75/(4+0.74) = 0.75/4.75 = 0.15789 call it 15.8oP or 1.063.

You could calculate the mass of extract in the first runnings, then use the remaining potential and the amount of sparge water added to calculate the oP of the second runnings.
Time is very important, second runnings could take 1/2 an hour or more to reach equilibrium - remembering that the first runnings have had an hour or so to equilibrate, second runnings wont take as long but it wont happen instantly either.

Fun bit of thinking
Mark

That's awesome Mark, I'll need to look at that.

You're right about the extract - though in this case, talking about lautering efficiency, less sugar and less volume increase seems to mean less retained in the grain, so very slightly increases lautering efficiency.

I haven't gotten into extract efficiency yet, with the intent to use this with Beersmith to get closer to expected efficiency when making big changes to grain bills. But I should include that.

Good point about the sugar concentration reaching equilibrium - in the case above, I would have been far better off doing a single sparge and letting it sit for 30-40min rather than two sparges of 15min or so... for a number of reasons.

 

[MartinOC]

... which is the point of the exercise in this thread.

Yep, I get the number-cruncher's technical-exactness (geeky) thing.

But, what happens when you get a "Yay! I hit all my numbers, but the beer was still crap" moment?

That's where the ART in brewing arises.

Edit: I mean the serendipity of creating a masterpiece on the fly, with what you have on-hand, on the spur of the moment.

That can only come from experience (& a bit of luck).

 

[Adr_0]

Agreed. I didn't mean to give that impression that it doesn't matter or its too hard. I should mention that I used to measure every little part, every run off etc. Its all learning and any comments I made was relevant to my findings. Do the hard, technical. fiddly stuff to find your comfort zone I guess. Eg. don't be surprized if you find you don't need to continue to do all that technical stuff to get consistent results.

I don't really plan to - this just tells me when two sparges are better than one and what I need to do with my volumes when I'm close to physical capacity in my mash tun.

Yep, I get the number-cruncher's technical-exactness (geeky) thing.

But, what happens when you get a "Yay! I hit all my numbers, but the beer was still crap" moment?

That's where the ART in brewing arises.

Hey buddy, don't try to make this about delicious delicious beer that you sit back and marvel at - those bizarre notions are best entertained on the Grainfather forum.

 

[MartinOC]

Hey buddy, don't try to make this about delicious delicious beer that you sit back and marvel at - those bizarre notions are best entertained on the Grainfather forum.

Hey buddy, back at ya!

Just take on board that I've been homebrewing for over 35 years & have probably chucked-out twice as many AG 50L batches than you've had birthdays.

'Used to sit on my bed, surrounded by text-books & tables, a calculator & a notepad, calculating every last detail of my next brew, then do it, only to find that it turned to shit.

I've also come home on a Friday night absolutely frazzled to the eyeballs from a mega-stressful job & gone "****-IT! I'm brewing" & created award-winning beers.

Nowadays, I use beersmith & it gets me in the ballpark of where I want to be.

I've never even thought about owning a Grainfather. Beaten-up kegs & re-purposed bits & pieces on a makeshift stand is all I need.

I gave-up on number-crunching to exact detail many years ago. I can still make great beer without it.

PLUR :beer:

Martin

 

[Danscraftbeer]

I don't really plan to - this just tells me when two sparges are better than one and what I need to do with my volumes when I'm close to physical capacity in my mash tun.

Consider a bigger mash tun so you don't have to worry about that capacity limit. I think I'm lucky to have started with an oversized 75lt Esky. Reason being water to grain ratios.
40lt brews. I can increase that if I top up with water etc.
1st infusion is 2.5l/kg water mash ratio. I usually make that a protein rest at ~50c.
2nd infusion (boiling water) gets to 3.5lt/kg Scarification rest.
Decoction for mash out optional and batch sparge with an equal water to grain ratio (enough water to cover the grain) each batch sparge.
I sparge 2, 3 times. Maybe 4. depends on the feel of the brew when they are different every time.
Sparge until your run off is ~ 1.010. Boil down accordingly. That's what I do anyway..

 

[manticle]

I approach my own brewing more like I do my cooking these days too but it's specifically a technical, numbers/data type thread - the aim is not to woo pinch of salt brewers.

Also the way I brew does not impact my deliberate reading about science, maths and technique and the passion that drives that level of detail carries a creativity and art of its own.

 

[Adr_0]

Hey buddy, back at ya!

Just take on board that I've been homebrewing for over 35 years & have probably chucked-out twice as many AG 50L batches than you've had birthdays.

'Used to sit on my bed, surrounded by text-books & tables, a calculator & a notepad, calculating every last detail of my next brew, then do it, only to find that it turned to shit.

I've also come home on a Friday night absolutely frazzled to the eyeballs from a mega-stressful job & gone "****-IT! I'm brewing" & created award-winning beers.

Nowadays, I use beersmith & it gets me in the ballpark of where I want to be.

I've never even thought about owning a Grainfather. Beaten-up kegs & re-purposed bits & pieces on a makeshift stand is all I need.

I gave-up on number-crunching to exact detail many years ago. I can still make great beer without it.

PLUR :beer:

Martin

My philosophy is to understand something fairly well, then step back taking away the key points - and it will be the same with this, but I needed to know how I should handle various grain sizes on my new setup and that needed some calculation.

Believe it or not, I generally like to keep things simple. This doesn't mean being ignorant of the mechanisms and detail, it means doing enough of what's necessary without going overboard. I suspect you fall into this same category - you don't go into detail each brew, but have the knowledge from having gone into detail once or twice before.

I can't control my age, as you can't control yours, but I can recognise that each day and each brew I can learn something new - as I'm sure you can.

I approach my own brewing more like I do my cooking these days too but it's specifically a technical, numbers/data type thread - the aim is not to woo pinch of salt brewers.
Also the way I brew does not impact my deliberate reading about science, maths and technique and the passion that drives that level of detail carries a creativity and art of its own.

Yay. I hope you are implying I'm under that umbrella too, because I certainly think I am...

 

[Adr_0]

Consider a bigger mash tun so you don't have to worry about that capacity limit. I think I'm lucky to have started with an oversized 75lt Esky. Reason being water to grain ratios.
40lt brews. I can increase that if I top up with water etc.
1st infusion is 2.5l/kg water mash ratio. I usually make that a protein rest at ~50c.
2nd infusion (boiling water) gets to 3.5lt/kg Scarification rest.
Decoction for mash out optional and batch sparge with an equal water to grain ratio (enough water to cover the grain) each batch sparge.
I sparge 2, 3 times. Maybe 4. depends on the feel of the brew when they are different every time.
Sparge until your run off is ~ 1.010. Boil down accordingly. That's what I do anyway..

I brew on a shelf frame, which is quite compact. I just can't fit anything bigger - and besides, we'll always have bottleneck somewhere, and we all have to recognise and appreciate that.

If you have a big volume in your mash tun, you do realise that you can dilute your sparges and get the same final gravity and same preboil volume with only one or two sparges?

It's up to you - it's your time and your effort - but 3 or 4 sparges is ridiculous.

 

[fungrel]

I approach my own brewing more like I do my cooking these days too but it's specifically a technical, numbers/data type thread - the aim is not to woo pinch of salt brewers.

Also the way I brew does not impact my deliberate reading about science, maths and technique and the passion that drives that level of detail carries a creativity and art of its own.

Well said.

 

[Fraser's BRB]

Not to derail the thread and feel free to move post elsewhere, but something that was said earlier has me curious.

On my 3V rig, I've always batch sparged (equipment limitations mean fly sparging is currently out of reach), I have two mash tuns, one 30L and the other 50L, the smaller is easier and gets good results, but doesn't handle the larger grain bills for high gravity brews. I have heat control for adjustments to strike temp if required as I'm using pots/keggles over flame for my mash tun.

I've always used around 3L/kg of grain bill, so generally 20L to 6.5kg grain, and then done 2 x batch sparges of 9L (my HLT only holds 18L) which gets me to my required boil volume for 60min boils and using Beersmith 2 gets me my pre-boil and OG numbers within a point or 2 based on 65% brehwouse efficiency (which I understand is different from mash efficiency and also quite low). Occasionally I've tested the gravity on final runnings and been above what would be considered risky for tannins etc.

So, my question relates to an earlier comment, do some/many of you keep sparging until you've gotten the most sugar/gravity possible and then do a longer boil to get down to the required volume/OG in order to get higher efficiency? Or do most do it the way I've described above and stop once you've gotten expected volume and pre-boil gravity?

Follow up question, outside of the obvious advantages of less grain and water (less $ and ability to do higher gravity brews in a smaller mash tun) does higher efficiency lead to better beer, or is hitting the numbers all that matters?

 

[Adr_0]

Not to derail the thread and feel free to move post elsewhere, but something that was said earlier has me curious.

On my 3V rig, I've always batch sparged (equipment limitations mean fly sparging is currently out of reach), I have two mash tuns, one 30L and the other 50L, the smaller is easier and gets good results, but doesn't handle the larger grain bills for high gravity brews. I have heat control for adjustments to strike temp if required as I'm using pots/keggles over flame for my mash tun.

I've always used around 3L/kg of grain bill, so generally 20L to 6.5kg grain, and then done 2 x batch sparges of 9L (my HLT only holds 18L) which gets me to my required boil volume for 60min boils and using Beersmith 2 gets me my pre-boil and OG numbers within a point or 2 based on 65% brehwouse efficiency (which I understand is different from mash efficiency and also quite low). Occasionally I've tested the gravity on final runnings and been above what would be considered risky for tannins etc.

So, my question relates to an earlier comment, do some/many of you keep sparging until you've gotten the most sugar/gravity possible and then do a longer boil to get down to the required volume/OG in order to get higher efficiency? Or do most do it the way I've described above and stop once you've gotten expected volume and pre-boil gravity?

Follow up question, outside of the obvious advantages of less grain and water (less $ and ability to do higher gravity brews in a smaller mash tun) does higher efficiency lead to better beer, or is hitting the numbers all that matters?

Yeah good question. The strict number of efficiency doesn't really matter, but if you're getting in the 50's or 60's mash efficiency (conversion efficiency x lauter efficiency) you can technically save a bit of $ and some space in your mash tun by using less grain. 65% brewhouse/70% mash? is not terrible but I'm sure a few more points wouldn't hurt.

Without doubt the important part is predictability.

So the purpose of this spreadsheet was to get a little predictability and see some of the limitations of my equipment and I believe it's done that. I've attached a starting table if you're interested.

First, I will assume that your conversion efficiency is 100%:
- All grain is properly cracked
- All weight of grain is accurate and moisture content is per Beersmith/etc
- Grain extract has been considered
- Mash pH, time and temperature are all suitable
- No d'oh-balls or dead spots in the mash

Once you have basically converted all of the kg of starch to sugar, lautering efficiency comes into it. To get the highest possible efficiency, yes you can go down to a particular gravity (e.g. 1.010) and then boil all of this off. Fly spargers may measure SG and pH if they think they will get close to being risky, but probably won't if they are not targeting a massive sparge volume.

65% efficiency is possibly a bit low - that's your call - and possibly represents 70% mash efficiency at a guess. One thing for me is that if you don't have an appreciation for where you're losing lautering efficiency - or conversion efficiency - you can get hurt doing bigger batches, where you might expect to hit 1.080 and only hit 1.065 - enough to throw a few things out.

I would suggest in your case your sparges are too stiff (water to grain ratio of ~1.3L/kg) which puts a lot of pressure on sugar concentration in the sparge water - which takes time and will be at too high an equilibrium concentration to get that much benefit out - assuming your grain bed is covered. You should possibly aim for a single sparge and possibly more strike water if your mash tun is a touch small.

Have a look at the spreadsheet - I've done two examples for 6.5kg where the example you described has a theoretical first runnings efficiency of 61%, and while the sparges will add more you are only going to get a fraction of the potential due to your LGR being impractically low. You are potentially better off using a more dilute single sparge if you have the space... so I've done another slightly different example.
View attachment Sparge-Efficiency-Calculator.xlsx

Have you measured your mash tun? Is it exactly 30L or slightly less/more?

 

[Adr_0]

It also depends where you've got room - if you can increase your preboil volume in the kettle and perhaps drain 60-70% of your HLT then refill, then you can open up more efficiency and use two sparges. But you'd need a heap more room in your kettle (45-50L) and also your mash tun, so I'd suggest trying a strike of 21-22L and a single sparge of 16-18L and see how that ends up.