• Welcome to the new forum! We upgraded our forum software with a host of new boards, capabilities and features. It is also more secure.
    Jump in and join the conversation! You can learn more about the upgrade and new features here.

BHE based on immersion chiller vs CFC

bougie1st

Master Brewer
Joined
May 21, 2016
Messages
77
Reaction score
1
Hi Brad

I had posted this in another thread and it was suggested to put it in as a suggestion, so copying to here.

One thing I have just noticed is that it seems to me that BS2 is including the loss to trub in the shrinkage calculation.  For example, in my latest brew, I have the following (measured variables) in BS2
Pre-boil vol 30.48L
Pre-boil gravity 1.051
Post boil volume 27.37L
Boil off 2.8L, evaporation rate 9.3% (note - I changed the est pre-boil vol to 30.17 to get the same post boil volume, in reality it was a boil off of 3.12L and 10.23%, but this doesn't affect my question, as the post boil volume is the same)
Shrinkage 2.47L, 9.01%
Trub loss 0.9L
Final volume (meas batch size) 24L

With my real numbers, I have taken the loss to trub from the post boil volume, then subtracted the shrinkage.  So this is 27.37 (post boil) - 0.9 (trub) - 2.46 (shrinkage value) leaving 24 L.  This gives me a shrinkage value of 9.31%, not 9.01%.

From this, it seems to me that the trub loss is included in the shrinkage (ie, everything at the end of boil undergoes shrinkage), then it is taken away.  Is this how it is supposed to be? 

Thinking about it, it probably works with an immersion chiller, but I am using a counter flow chiller, which means that the trub losses remain in the kettle and never undergo shrinkage (ok, maybe a few degrees as the whole thing cools down). 

As this influences the set variable (BHE, which I am actually coping with fine and am happy to continue to use), maybe there needs to be some consideration of cooling method in the equipment setup?
 

brewfun

Grandmaster Brewer
Joined
Sep 6, 2011
Messages
2,307
Reaction score
1
Location
Ventura, CA
bougie1st said:
This gives me a shrinkage value of 9.31%, not 9.01%.

From this, it seems to me that the trub loss is included in the shrinkage (ie, everything at the end of boil undergoes shrinkage), then it is taken away.  Is this how it is supposed to be? 

Thinking about it, it probably works with an immersion chiller, but I am using a counter flow chiller, which means that the trub losses remain in the kettle and never undergo shrinkage (ok, maybe a few degrees as the whole thing cools down). 

Yes. Trub/chiller loss is calculated as a room temperature value. It can show up as part of the shrinkage volume, but not for the reason you outlined. This happens when the Calculate Boil Volume box is checked because the loss is added to the required amount needed to meet your batch size. With the box unchecked, no change happens. This is normal behavior for BeerSmith.

I'm curious how you get more than 4% contraction, though. There just isn't that kind of expansion from room temperature to boiling. I think you mean it as a percentage of wort that's lost, which reduces BHE?

Your total shrinkage should be no more than 1.09 liters for the whole batch. In fact, your counterflow chiller should pull 0.1 liter more hot wort, than if you used an immursion chiller and pulled chilled wort. All of that is captured in BHE, though.
 

bougie1st

Master Brewer
Joined
May 21, 2016
Messages
77
Reaction score
1
Thanks, Brewfun.

Sorry for the late reply - very busy with work the last couple of weeks.  I'll try playing around to see what happens when I uncheck the calculate boil volume box.

WRT the shrinkage, I am still using two spreadsheets for my brewdays - Bru'n water, as I still can't figure out the new pH stuff in BS2, and am waiting on either a video from Brad or more guides, etc - and another that I record all my volumes.  This latter one will probably go considering the new upgrade, but not just yet.  Until, at least, I can finally figure out the little things in BS2, such as this with the losses. 

During my brewday, I run with a calculated estimate of volumes based on the height of the wort/water, knowing my system and using cylinder volume calculations.  When I am putting in the mash water, I measure from the floor up with a ruler, but once it is boiling etc, I measure from the top down (I do a calibration measurement too - once the mash in water is ready, I measure from top and bottom, to make sure they correlate).  There is always a small variance in this (ie measured volume physically put in, measured volume from bottom, measured volume from top).  I then always assume that there is some variance in the other measurements I make (eg trub left at bottom after wort removal). 

Basically, I figure that these losses/inaccuracies are accounted for when I measure the 'shrinkage' at the end.  I generally get somewhere between 7-9% shrinkage at the end, and the difference between the anticipated 4% (1.09L) and 7% (roughly 1.8L - I didn't calculate that specific number here, just an estimate of what I get) I assume to be due the the various small inaccuracies throughout the process.  As long as my numbers are consistent through this, I haven't felt it necessary to get more specific, and my calculations account for these losses, meaning I get my target volume into the fermenter and bottle/keg most of the time.  It's just how my system works and I measure enough points as it is.  RDWHAHB I figure.

Maybe that seems discordant with some of my posts on here - but they've been more about the specifics of using BS2 and how it's set up, rather than the small errors/variances of my brewing. Once I know how to account for these variances in BS2 itself, moulding my processes to the program, because I have to (there are thousands of users and it isn't individually customisable, but I also really like the program and find it immensely useful), then I can get rid of the spreadsheets!  Looking forward to that day, but it isn't here just yet.
 

bougie1st

Master Brewer
Joined
May 21, 2016
Messages
77
Reaction score
1
brewfun said:
Yes. Trub/chiller loss is calculated as a room temperature value. It can show up as part of the shrinkage volume, but not for the reason you outlined. This happens when the Calculate Boil Volume box is checked because the loss is added to the required amount needed to meet your batch size. With the box unchecked, no change happens. This is normal behavior for BeerSmith.

I'm curious how you get more than 4% contraction, though. There just isn't that kind of expansion from room temperature to boiling. I think you mean it as a percentage of wort that's lost, which reduces BHE?

Your total shrinkage should be no more than 1.09 liters for the whole batch. In fact, your counterflow chiller should pull 0.1 liter more hot wort, than if you used an immursion chiller and pulled chilled wort. All of that is captured in BHE, though.

Hi Brewfun
I've just gone back and looked at that recipe - the calculate boil volume wasn't checked.  I manually enter the Est Pre-Boil Volume (with the actual volume in Measured Pre-Boil Vol) to force BS2 to calculate the correct Post-Boil Vol.  I'd expect that this is how it has to be, because all of these are estimates, and the batch-to-batch variability would mean that you'd have to have it super-dialled in to get it perfect every time.  Trub loss is entered manually after this calculation, and shouldn't be included in the shrinkage.

Sorry to appear daft, but, if the calculate box isn't ticked (as in my example here), I don't understand how or why BS2 is doing this as part of its normal behaviour.

Could you please elucidate further as to why BS2 is set like this and how to set it up correctly for my equipment (ie with a CFC)?  I don't understand it from what you had written previously.

Can I also just take a sec to say a big thank you to you, Brewfun, and to Oginme?  You two are always on here, helping us out with your understanding of the program.  It's really very helpful and kind of you (as well as patient!).  Thanks!
 

bougie1st

Master Brewer
Joined
May 21, 2016
Messages
77
Reaction score
1
So, Brewfun, you've inspired me to go looking for the differences between BS2 and my measurements

I just completed another brew, and found a few areas of difference
1. I hadn't accounted for volume loss to hops in hop spider - (doh!)
2. BS2 underestimated by volume lost to absorption by 0.29L
3. BS2 underestimated the pre-boil volume by 0.38L
So now I have an unaccounted value of 0.28L, which I am happy to put down to inaccuracies, etc, but will keep investigating

I had the calc boil vol unchecked, but adjusted the est pre-boil vol to get the same post boil vol in the BS2 calculation as I measured.  Funnily enough - it was exactly the same as BS2's calculated value, despite the differences above!  Ie, when I checked the box just to see what BS2 calculated, it got the post-boil volume bang on, even though there were discrepancies in the steps above.

Is there a link as to the equation that the calc boil vol uses so that I can look at those figures to understand how this is calculated better (as you'd said it influences the trub/shrinkage calculations)?

Thanks again
 

Oginme

Grandmaster Brewer
Joined
Mar 16, 2013
Messages
3,182
Reaction score
23
Location
New Hampshire, US
The calculation for pre-boil volume is really pretty straight forward.  BeerSmith starts with the volume to the fermentor as it's fixed variable.  It then adds the loss to trub and chiller and boil losses to come up with the pre-boil volume.  This is then adjusted for thermal expansion.  The default for BeerSmith for thermal expansion is 4%.  So in short:

Pre-boil volume = [volume to fermentor + loss to trub and chiller + boil off rate * hrs of boil] * (1 + thermal expansion value)

It is really easier to 'dial-in' your profiles and losses if you allow the software to calculate the pre-boil volume for you.  Then changes you make to the equipment profile will be reflected in the estimated volumes and you can more easily follow and troubleshoot where your entered values in the profiles are off.

You can adjust the volume loss for grain absorption by converting the value to oz of water/oz of grain and updating that figure in the universal settings of BeerSmith.  I would highly recommend that you keep a record of changes made each time you adjust your profiles and the global settings so that you can easily undo or look to see what these values were if something else needs to be tweaked or looked at.

 

bougie1st

Master Brewer
Joined
May 21, 2016
Messages
77
Reaction score
1
Thanks, Oginme

I'll keep playing.

I appreciate your input.  I think that it highlights the biggest shortcoming of the system though - it doesn't make it easy to dial in your equipment, and it doesn't easily account for where things have varied from its assumptions.  What I mean by this is that you can't enter all of your actual measured variables at all the points of the process to compare to the calculated variables.  Why the calculated variables are based on great math/science/experience, they give one number, and it isn't always easy to find the answer to where things went wrong (except, of course, if you've had a shed load of experience with the program, such as experts like yourself).  There are many questions on the forum that highlight newer users' inability to find easily where things went wrong.

Since this is in a suggestions post, I'd add an easy ability to add all of your measurements at the various points of brewing and then being able to generate a report for your brews comparing calculated and actual results.  From my previous post, an example is actual vs assumed grain absorption.  This would make it easier to dial in a system, rather than either guessing or (as I'm doing) running an extra spreadsheet alongside that I enter my actual numbers into to compare and find where the differences are.

Another is a better manual for the program, to explain how to do these things.  That would save a lot of time for users and for people like yourself and brewfun answering similar questions over and over again.  Furthermore, tool tips to explain things better (eg the new pH water setup doesn't explain what water volumes to use), rather than mostly just rehash the name of the box that the data is entered into.

Anyway, this thread is now way off topic (but I appreciate being able to engage you both on some of the finer points of the system here) - back to the original post.  I'm still not sure that BS2's shrinkage calculation is setup for CFC chilling from my calculations.  If, as brewfun noted, the calc boil vol box is checked, he/she has said it can be included in the shrinkage volume, then it would indicate that BS2 doesn't make a distinction between immersion vs CFC.  The only place this can be picked up is in BHE, which means we are using a very broad brush approach to account for the difference (100mL per brewfun's post) and it is very hard to account for it (being a fraction of a percent).  Again, this removes accuracy for determining where losses are, with the assumption it will just be picked up in BHE.

Thanks again
(BTW - I still love BS2 and find it great, just trying to understand it!!)
 

Oginme

Grandmaster Brewer
Joined
Mar 16, 2013
Messages
3,182
Reaction score
23
Location
New Hampshire, US
Honestly, if I could measure close enough to distinguish 100 ml I would be thrilled!  I have my fermentors marked off in 0.5 liter increments.  My most accurate measurements are water in and trub which I can measure to the nearest 10 ml.  Hot measurements are to the nearest 0.25 liters.  0.1 liters gets lost pretty easily in those error bands.

 
Top