Equal Runnings BIAB

[pricelessbrewing]

So had a discussion last week regarding Braukaisers findings on batch sparge efficiency being tied to the ratio of first runnings and second runnings, and how that might translate over to BIAB.

My initial intuition lend me to believe that the second runnings would be a much lower gravity due to the higher absorption rate common amonst BIAB brewers, and so any "lauter effeciency" gained by splitting your runnings would be fairly negligible. However we went back and forth, and eventually I said F it I'll do a couple batches and see what happens.

So I did. Twice. Need more data points, but here are the preliminaries.

 

[pricelessbrewing]

Todays brew day was a riff on Zombie Dust. Most things stayed the same, played with the mash profile a little bit to explore another concept brought up recently, and I will be using 1028 instead of 1988 London ESB since I have some yeast harvested from a starter already and I'm cheap

Mash Efficiency Analysis

15 minute 1.053 Conversion efficiency thus far ~65%
20 minute 1.059 Conversion efficiency thus far ~73%
27 minute 1.063 Conversion efficiency thus far ~ 78.5%
33 minute 1.065 Conversion efficiency thus far ~81.5%
38 minute 1.067 Conversion efficiency thus far ~84%
49 minute 1.071, and there it stayed. Conversion efficiency thus far ~92%



Second runnings 1.018

Combined runnings 1.041

Strike with 0.76 Gallons at 163. After dough in mash was at 148.5, slightly lower than intended but that's alright. I left it at 148 for about 5 minutes, then I turned my mash tun (slow cooker) to high, and raised the temp to 152 over about five minutes for the rest of the mash.

First runnings 3.48" 0.606 Gallons. 1.071 SG. Conversion Efficiency 92%
Second runnings 2.5" 0.73 Gallons 1.018 SG. Lauter Efficiency ~93%
Combined runnings/preboil 4.5" 1.31 gallons (perfect!) 1.041 SG

Estimated Full volume "lauter' efficiency: 85%. (OG difference is 2 point. Negligible) My experience does bias me slightly in this regard, and I believe that greater conversion efficiency occurs at thinner mashes, but the "lauter efficiency" suffers due more sugars remaining in the grains after the grain bag is pulled. I may explore this later and use the leftover sugar for making starters...

Continued the mash for 75 minutes while my sparge water heated up in main brew kettle. Assuming homogeneous gravity, ending my mash at 30 minutes would've lost me about 10% conversion efficiency and put my overall BH efficiency at 63-64%. My intuition is the thicker mashes take longer to convert, and I don't have as tight of a grind at the new LHBS as I'm used to. I may do a triple mill next time, or try bringing a spray bottle and doing a little malt conditioning which some claim offer more a consistent grind.

Mash Efficiency Analysis

Estimated Full volume "lauter' efficiency: 85%. (OG difference is 2 point. Negligible)

My experience bias me slightly in this regard, and I believe that greater conversion efficiency occurs at thinner mashes, but the "lauter efficiency" suffers due more sugars remaining in the grains after the grain bag is pulled. I may explore this later and use the leftover sugar for making starters...

 

[pricelessbrewing]

Angus Og Extra Special Bitter aka My first recipe (info later)

Equal Runnings BIAB

10 minutes 1.038 62.3% of total conversion (NOT conversion efficiency)*
15 minutes 1.043 70.5%
23 minutes 1.050 82.0%
38 minutes 1.058 95.1%
45 minutes 1.061 100%
55 minutes 1.062 101.6% (Outlier, probably was slightly above calibration temp still, or didn't stir the wort enough)
65 minutes 1.061 100%

Second runnings 1.021.
Combined runnings 1.038 Total mash efficiency unknown*

First runnings volume 2" (kettle) 0.582 Gallons. 1.061 SG
2nd runnings: 3.75" (slow cooker) 0.717 Gallons. 1.021 SG
Combined runnings/Pre Boil: 3.8" (kettle) 1.106 Gallons. 1.046

Estimated Lauter Efficiency 93.6%. Conversion Efficiency Unknown. Mash Efficiency Unknown.

Had to add some more water unfortunately, as I didn't measure my strike water appropriately (didn't have my trusty ruler yet) and hadn't nailed down my new boil off rate so added .5G throughout the boil (from a separate pot of boiling water).

*Also unfortunately, I cannot properly speculate on the mash efficiency for this mash due to me being a clumsy consumer an spilling about a cup of grains when milling. Not usually a big deal, but when the total grain bill is only 1.93 LB it's a not insignificant amount. I threw in a hand full of base malt and said good enough...

 

[doug293cz]

So had a discussion last week regarding Braukaisers findings on batch sparge efficiency being tied to the ratio of first runnings and second runnings, and how that might translate over to BIAB.

My initial intuition lend me to believe that the second runnings would be a much lower gravity due to the higher [should be lower] absorption rate common amonst BIAB brewers, and so any "lauter effeciency" gained by splitting your runnings would be fairly negligible. However we went back and forth, and eventually I said F it I'll do a couple batches and see what happens.

So I did. Twice. Need more data points, but here are the preliminaries.

I'm late responding to this thread since I was on vacation in an internet dead zone (yes there still are such places )

I think the OP misspoke where I highlighted the quote in red.

In a batch sparge, the gravity of second (and subsequent) runnings will be determined by how much sugar is retained in the MLT/grain after the previous run-off, and how much water is added for the sparge. The higher the grain absorption (and undrainable volume), the more sugar is retained in the MLT/grain, and the higher the gravity of subsequent runnings will be. Since BIAB'ers usually obtain lower grain absorption (and zero undrainable volume), there is less sugar left after run-off, and therefore subsequent sparge steps will have lower gravity than is the case for a traditional MLT. Another way to look at this is that the lower your grain absorption, the less efficiency benefit you will achieve by sparging.

But the above is independent from the dilution math that determines optimal run-off ratios. So BIAB or traditional, maximum efficiency is obtained with equal run-off volumes. I'll see if I can put together a "reasonably simple" explanation of the math that demonstrates this.

Brew on

 

[pricelessbrewing]

I'm late responding to this thread since I was on vacation in an internet dead zone (yes there still are such places )

I think the OP misspoke where I highlighted the quote in red.

In a batch sparge, the gravity of second (and subsequent) runnings will be determined by how much sugar is retained in the MLT/grain after the previous run-off, and how much water is added for the sparge. The higher the grain absorption (and undrainable volume), the more sugar is retained in the MLT/grain, and the higher the gravity of subsequent runnings will be. Since BIAB'ers usually obtain lower grain absorption (and zero undrainable volume), there is less sugar left after run-off, and therefore subsequent sparge steps will have lower gravity than is the case for a traditional MLT. Another way to look at this is that the lower your grain absorption, the less efficiency benefit you will achieve by sparging.

But the above is independent from the dilution math that determines optimal run-off ratios. So BIAB or traditional, maximum lauter efficiency is obtained with equal run-off volumes. I'll see if I can put together a "reasonably simple" explanation of the math that demonstrates this.

Brew on

Correct will edit, thanks for the catch.

Maximum lauter efficiency is always obtained with equal runnings (for batch sparges), and my past couple brew days have confirmed this. As I mentioned in my pm's though, my intuition says that conversion efficiency is typically higher with full volume mashes, and so that's why BIABers still get 70-75% as their average while if the conversion efficiency remained constant it may be 65-70%. If you raise your conversion %, by say 5%, then you will compensate for most/all of the loss in lauter efficiency. However I don't know of anyone research done that has found a link between the two, just where conversion efficiency is held as a constant near 100%. For the sake of simplicity, all of the following graphs and data assumes 100% conversion efficiency, so lauter efficiency = mash efficiency. Moreover, I assumed 0 volume loss at the mash tun as this is another variable that has a lot of play but I didn't want to mess with.

Stop, Graph time!

Ran a bunch of simulations using Dougs batch sparge analysis simulator after I made some modifications to it of course, mostly to let me a bunch of simulations at once using what-if data tables.

This graph describes the difference in lauter efficiency when performing a no sparge/full volume mash, a single batch sparge with equal runnings, and a double batch sparge with equal runnings.

So for single sparge 0.08 Gal/lb at 20 lbs, the efficiency gained by doing so is roughly 8.9% lauter efficiency. A double sparge nets you an additional ~2.6% lauter efficiency. Together, you gained ~11.5% lauter in comparison to doing a full volume mash.

The interesting thing to me is the very different curves that the data follows, where for traditional mash tun brews a single sparge is nearly linear while the biab sparge falls off much more quickly for very big beers.

Lauter efficiency as a function of grain bill, assuming the same process and no over sparging and extended boils. Again, you can see the lauter efficiency gains for exceptionally big beers decreases with the grain bill as well as the general efficiency. In my opinion, you would be better off planning for the efficiency loss, and doing a partigyle, than doing an extended boil. Or doing a second very large sparge, and blending the two beers together, but then you have to mess with hop utilization which may be more annoying than it's worth.

A re-production of braukaisers effeciency curves as a function of the ratio of run offs. Now there's a slight change in terminology definition here, my run off ratio is the ratio of the 2nd runnings to the first runnings, and not the first runnings as a ratio of the total runnings volume. So 1 represents an equal runnings batch sparge, and while his representation was a value of 0.5 which I felt was slightly vague when dealing with more than one sparge...

Anyways, the numbers line up, I only took it out to 1.3 instead of 2.0 because I'm lazy and the graph is symmetric...

Finally, the graph that started the whole thought experiment. Is BIAB lauter efficiency that much different than mash tun lauter efficiency? Short answer: no. Longer answer: the lower grain absorption, merely translates the curves up and down, it does not actually change the derivative of the curve. So while it does gain you some lauter efficiency, that advantage is relatively constant. As you can see, a similar translation occurs as the grain bill increases.

Hope other people find this interesting and it can provoke some sort of discussion. I'll be implementing a lauter efficiency estimation in my (http://pricelessbrewing.github.io/BiabCalc/TestingA) with credit to doug and braukaiser.

 

[pretzelb]

This is probably a stupid question but can you explain the sparge amounts and method? I'm confused as to what we are calling first and second runnings. Since this isn't a full volume biab you must be calculating something in reserve for sparge but I'm not sure what percent or ratio.

My guess is you picked a sparge amount and then divided it by two for "equal" runnings. Then I guess you pulled the bag and maybe put it over another pot? Where you then just quickly dumped the first sparge water over it and measured the results? And then empty the pot (into the original mash pot) and repeat with a second quick dump of same amount? I'd also be interested in time you allowed for the bag to stop dripping and if any squeezing was done.

Looking at the numbers of .76 strike, .606 and .73 for runnings, and final of 1.31 I can see that what I describe is not what was done. Just adding .606 and .73 is 1.36 and that exceeds the final 1.31. I'm sure I'm being stupid and it's obvious but I can't figure it out.

 

[pricelessbrewing]

This is probably a stupid question but can you explain the sparge amounts and method? I'm confused as to what we are calling first and second runnings. Since this isn't a full volume biab you must be calculating something in reserve for sparge but I'm not sure what percent or ratio.

My guess is you picked a sparge amount and then divided it by two for "equal" runnings. Then I guess you pulled the bag and maybe put it over another pot? Where you then just quickly dumped the first sparge water over it and measured the results? And then empty the pot (into the original mash pot) and repeat with a second quick dump of same amount? I'd also be interested in time you allowed for the bag to stop dripping and if any squeezing was done.

Looking at the numbers of .76 strike, .606 and .73 for runnings, and final of 1.31 I can see that what I describe is not what was done. Just adding .606 and .73 is 1.36 and that exceeds the final 1.31. I'm sure I'm being stupid and it's obvious but I can't figure it out.

First and second runnings usually aren't called for in BIAB since the majority of people do full volume mashes. It's a term borrowed from batch sparging, and since dunk sparging is batch sparging I'm applying it here. Basically for equal runnings you want to take your post mash volume and divide it in two, that's your sparge volume. Your strike volume is your sparge volume + grain absorption. You can see this in my in progress version of My biab calculator

Yeah, so I didn't have a proper way to measure my volumes as accurately as I would like. I now have another stainless ruler to measure my heights, but that's the general premise.

For equal runnings you want the volume left behind after you remove the grain bag and squeeze to your preference, and the amount of sparge volume to be the same. In reality, as long as it's close it's pretty much the same lauter efficiency as as long as it's somwhere between .8 and 1.2 you'll pretty much the same lauter efficiency. This would've been .83~ sparge volume ratio.

As far as the sparging process I used it was dough in, mash, pull grain bag and let it drain until it slows, then dunk into another pot of heated water (160~, don't have my notes in front of me), open the bag up, stir like mad, let it rest for 5~ minutes, stir like mad, then pull the grain bag, suspend bag over brew kettle, combine runnings, and proceed to boil.

Disclaimer:This was all for a small batch, and I had weighed my grains using the LHBS scale that wass not very accurate at low weights, and I didn't have my ruler yet so all the measurements have a bit of instrumentation unit error. I've since bought a 0.01g scale, and a stainless ruler to measure volumes. This should help ensure accuracy on any reproductions.

 

[pretzelb]

So in the first example with .76 strike you had .76 in two pots, one for mash and the other for the dunk? If so I can see how this would require more equipment as the batch size got bigger.

 

[pricelessbrewing]

Yup I used a 1 gallon slow cooker for the mash tun and a 2 gallon stock pot for my brew kettle. Would actually be useful for setups that want to do a larger beers but couldn't fit a full volume mash.

 

[Gavin C]

Hey Priceless.

I'd be interested in seeing these graphs plotted with a 0.045 gallons/pound absorption. This is pretty much a constant value on my setup.

Cool thread BTW. I like graphs

 

[pretzelb]

Yup I used a 1 gallon slow cooker for the mash tun and a 2 gallon stock pot for my brew kettle. Would actually be useful for setups that want to do a larger beers but couldn't fit a full volume mash.

OK, I think I get it now (finally).

I might post back later with some test figures after entering numbers into BeerSmith to make sure I have the concept down.

 

[doug293cz]

Hey Priceless.

I'd be interested in seeing these graphs plotted with a 0.045 gallons/pound absorption. This is pretty much a constant value on my setup.

Cool thread BTW. I like graphs

Gavin

Can you describe what you want plotted vs. what? I figured out how Priceless modified my spreadsheet to make the nice graphs, so now can also crank these out. Here's a test I did, but it's a little off topic cause it's no sparge.



The above is for 6.75 gal pre-boil, 5.5 gal post-boil, assuming 100% conversion efficiency.

Brew on

 

[Gavin C]

Gavin

Can you describe what you want plotted vs. what? I figured out how Priceless modified my spreadsheet to make the nice graphs, so now can also crank these out. Here's a test I did, but it's a little off topic cause it's no sparge.

View attachment 311923

The above is for 6.75 gal pre-boil, 5.5 gal post-boil, assuming 100% conversion efficiency.

Brew on

Great information Doug.

As I mentioned to you before it rings very true to what I'm seeing for FVM at 0.045 and ~7 gallon pre-boil volumes

I would be interested to see what the equal runnings plots (like the ones priceless showed earlier) would look like with this grain absorption (0.045) in mind.

 

[pricelessbrewing]

Glad you figured it out Doug sorry about the delay, something came up this morning. Let me know if you'd still like me to email you my modifications.


@Gavin I'll run your absorption rate through my version and report back with a couple graphs, maybe a half hour?~

 

[Gavin C]

Glad you figured it out Doug sorry about the delay, something came up this morning. Let me know if you'd still like me to email you my modifications.


@Gavin I'll run your absorption rate through my version and report back with a couple graphs, maybe a half hour?~

No rush mate. I'm just curious as to what the plot looks like. This topic is pressing all my nerd-maths-buttons.

 

[doug293cz]

No rush mate. I'm just curious as to what the plot looks like. This topic is pressing all my nerd-maths-buttons.

Here's an easier to read version of the one above just for you.




Edit: Above is for 6.75 gal pre-boil, below is 7.0 gal pre-boil. The extra water improves efficiency a little.



Brew on

 

[pricelessbrewing]

Since I can't use @Gavin...

This image shows what I suspect to be a pretty consistent trend, the lauter efficiency function for a single equal runnings batch sparge and a fixed grain bill is not changed much by the absorption rate, but a constant vertical offset is added that does depend on the absorption rate. I'll get around to doing a regression on these eventually, but it appears that the derivative of the lauter efficiency doesn't care what the absorption rate is.

However with three data points you can clearly see now that the lauter efficiency as a function of grain bill clearly changes both the derivative and the offset. As your absorption rate lowers, the lauter efficiency function gets increased, and while it remains a decaying function it becomes much more linear. For comparison, look at the three next graphs.

Lastly, an updated version of the lauter efficiency gained by doing equal running batch sparges. Here the variables are grain bill, absorption rate, and the number of sparges done.

An important couple things I've gleamed here.

For traditional mash tuners, and somewhat for BIABers, it is probably much more productive IMO to do a partigyle for unusually large grain bills rather than doing an extended boil. However, as you can see from the graphs, it may be slightly less of an issue with a setup like gavins. I would still probably do a partigyle since it's a cool technique and I'd rather get 2 beers out of 2 hr of boiling rather than 1.

It seems to me a simpler way to approach modelling lauter efficiency will be the remaining sugar in lb after sparging, it gives an equal answer but the math gets simplified a bit as some variables get cancelled out.

I had an error in my previous data table, the biab 0.08 gal/lb lauter efficiency vs grain bill curve was rather surprising and makes a lot more sense now that I corrected it.



PS: anyone know how to produce graphs online from variables in js or php?

 

[Gavin C]

Wow.

Need some time to digest all this brilliant info. Thanks a million @Pricelessbrewing

 

[doug293cz]

It seems to me a simpler way to approach modelling lauter efficiency will be the remaining sugar in lb after sparging, it gives an equal answer but the math gets simplified a bit as some variables get cancelled out.

Can you expand on this? I can't see off hand how using retained sugar to calculate efficiency is any easier than using recovered sugar.

Brew on

 

[pricelessbrewing]

Can you expand on this? I can't see off hand how using retained sugar to calculate efficiency is any easier than using recovered sugar.

Brew on

I'll have to write out the equations on paper to double check out a quick glance it made sense...

 

[doug293cz]

Glad you figured it out Doug sorry about the delay, something came up this morning. Let me know if you'd still like me to email you my modifications.

Unless you have made some significant changes in the basic calculation formulas, I don't need a copy. Thx.

Brew on

 

[pricelessbrewing]

Unless you have made some significant changes in the basic calculation formulas, I don't need a copy. Thx.

Brew on

Nope, just some restructuring in order to make the what-if tables easier to run. Changed the strike/sparge for equal run offs to first look for a cell that's a user input of the run off ratio, then if it's blank do the original calculation, if it's a number between 0 and 2 then determine the volume based on that ratio.

Also added a small table for entering the grain bill in lb, fine grind dry yield and moisture content, if those numbers are entered then it does a weighted average and fills in cell B9, otherwise it does a weighted average for the pt/lb/gal potential, if those are not provided it leaves it at 37.

 

[stainlessbrewer]

To each their own but you are completely over complicating brewing.

 

[pricelessbrewing]

meh. I like to understand what each variable effects. I knew a good deal less about this subject before re reading braukaisers findings and talking to Doug on the subject.

I'a big believer in simplicity of equipment, but don't let that equipment restrict your options. Batch sparging is a simple process and now I know very accurately what my mash efficiency will be. I'm always within 1-2 points, even with new recipes.