Author Topic: Recipe batch size and trub loss  (Read 6364 times)

Offline Dexmo

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Recipe batch size and trub loss
« on: June 12, 2015, 05:28:22 PM »
Hi,

So I was wondering why when I changed the value for trub loss from the boil kettle the grain bill never changed.  The significant effect of this was to add an equal amount of water to makeup the loss from trub and beer below the spigot, etc.  Yet a corresponding amount of grain and hops was not added.  The amount of beer needed increased but this was only offset by adding more water, thus diluting the strength of the beer in the kettle.  This is an obvious error.  I won't end up with the same beer in this kettle as I would had I not said I would loose any wort to the kettle.

Didn't make sense to me so I thought I'd search the subject and see what I could find.  Wow, this is no small subject.  The more I read the more I was confused (shocked really) as to why so many people seem to think this is OK and are willing to use a weird hack to work around it. 

In fact Brad even says on his website  ...
"Next you would need to account for all of the losses in the system from boiling forward. This would include boiling, which concentrates the wort (losing volume, but not gravity points), trub loss (which takes both gravity points and volume away) and any top up water added (which dilutes the wort). The calculation is a bit more complex, but can be done by tracking the changing volumes as well as gravity points remaining in the wort."

Notice he says trub loss which includes gravity points and volume.  He acknowledges in writing that trub loss includes gravity points yet when you tell the program you have trub loss it only increases the water, not the grain. 

Every batch I have brewed with this has been off because of the trub loss issue.  Anyone who brews with this program and enters a trub loss will be brewing a weaker version of the original recipe.  The more trub loss, the weaker the beer will be.

The only way to correctly use this program as-is would be to enter zero for trub loss and shoot for the volume you want in the kettle at the end of the boil (after shrinkage from cooling).  Period.  Not some hack whereby you makeup a total efficiency to hide the error.  That works until you change brewpots or trub loss or make a larger/smaller batch.  If you do that you need to hack another total efficiency number because it's not linear since it includes a fixed trub loss amount.

If you want 10 gallons of beer in your keg and you leave a gallon in the fermenter you need 11 gallons in the fermenter.  If you leave a gallon in the kettle when transfering to the fermener you need 12 gallons in the kettle after the boil (and cooling).  And your batch size needs to be 12 gallons.  Now if you are off in gravity you adjust the brewhouse efficiency, which at this point is really mash efficiency.  Mash efficiency in my opinion is what should adjusted to begin with.  This is the number that is variable depending on how well you extract the sugar from the grain.  That is the only efficiency variable.  After the mash the efficiency is solely based on a direct percentage of final boil volume to fermenter volume.

In fact, why stop at the fermenter for batch size?  I don't drink out of the fermenter.  What makes it into the keg to drink is the important part.  The losses in the fermenter don't even effect the brewhouse efficiency.  I could loose half the wort in the fermenter and my efficiency will be the same as if I didn't.  It seems to me its just an arbitrary decision to pick the fermenter as the batch size.

It seems unnatural to tweak the brew house efficiency to makeup for the trub loss.  The only variable in the whole process is how well you can extract the sugar out of the grain.  That's the percentage we should be entering.  After that it is all predetermined by simple ratios that can be applied to the adjusted mash efficiency.  That is the only thing that makes sense to me.

It is just plain wrong for the program to tell you to add water to your recipe without a proportional increase in grain.  It is setting you up to fail from the start.  Else so many people would not be posting asking why they constantly fall short of the predicted OG.

Say I want to make a batch of cookies.  I want 24 cookies so I decide to make a batch of 24 cookies worth of dough.  But I know that 4 cookies worth of dough will stick to the sides of my bowl.  So if I want to end up with 24 cookies in the oven I need 4 more cookies worth of dough.  Brad would tell me all I need to do is add 4 cookies worth of milk and I'll be fine.  No I won't.  I'll have soup.  My cookies will be runny.  The recipe will be off.  Can you see now why this makes a difference?  The program is telling you to add water to your recipe to make up for lost water AND sugar.  Does that seem right to you?  Do you think something like this will affect the composition of your beer?  Are you really saying no????

Since there seems to be so much disagreement on this perhaps the s/w could accommodate both sides and provide the option to base the recipe on the amount we want in the fermenter plus the amount we will leave in the kettle, taking the trub loss into account.  That way those of us who think it's broke can use the program like we think it should work and those who want to continue brewing their recipes short and compensating by increasing the brewhouse efficiency (which will bump the grain up to the same values as the proper recipe volume will show you) can blissfully continue doing their way.

Thanks,

Bob

Offline Oginme

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Re: Recipe batch size and trub loss
« Reply #1 on: June 12, 2015, 06:49:11 PM »
BeerSmith uses brewhouse efficiency as its user input variable for a recipe.  The program will adjust the mash efficiency to maintain the brewhouse efficiency.  I agree that this is kind of messed up, but it is the way the software works.  Once your profiles are sufficiently accurate, it is easy to figure the effect of a change in trub loss on the brewhouse efficiency given the same mash efficiency.

In my profile, I plan on a litre of loss to trub (for a 10 litre batch) which covers most except the hop heavy recipes.  This way may I leave a little bit of usable wort in the kettle for some recipes, but I cover the majority of what I brew.
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Offline brewfun

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Re: Recipe batch size and trub loss
« Reply #2 on: June 14, 2015, 07:36:08 AM »
Notice he says trub loss which includes gravity points and volume.  He acknowledges in writing that trub loss includes gravity points yet when you tell the program you have trub loss it only increases the water, not the grain. 

Hi Bob,

Mash Efficiency: The sum of conversion efficiency and sparge efficiency into the kettle.

Brewhouse Efficiency: The percentage of total sugar that makes it into the fermenter.

With brewhouse efficiency, if you say you'll get 80% efficiency, you're saying; of the total sugar available, even with losses, that's how much gets to the fermenter. That means that if you add losses to trub, you still have 80% going to the fermenter and will maintain the same gravity. Therefore, the ONLY place you can gain that sugar is with increased Mash Efficiency.

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The only way to correctly use this program as-is would be to enter zero for trub loss and shoot for the volume you want in the kettle at the end of the boil (after shrinkage from cooling).  Period.  Not some hack whereby you makeup a total efficiency to hide the error. 
<edit>
The only variable in the whole process is how well you can extract the sugar out of the grain.  That's the percentage we should be entering.

In the first part, you're establishing your mash efficiency.

The next step is to measure the fermenter volume and the resulting gravity. This represents two percentages:
1) The percent of usable wort from the kettle.
2) The percent of available grain sugar that can become beer.

The percentage is a reduction from the mash efficiency. However, if you overstate your sugar content you end up making the statement that you get more extraction from your grain. If that isn't the case, then your percentage of total sugar into the fermenter must go down.

What you'll find is that differing recipes will have different yields into the fermenter. So, if the target is to always have 5.5 gallons in the fermenter, then you must accommodate the loss, somehow. A Pilsner will have a greater brewhouse efficiency than a DIPA. Without adjusting for the hop loss, the two recipes will have identical kettle volumes, but very different amounts in the fermenter.

Brewhouse efficiency is more important in commercial brewing than in homebrewing because they need to have predictable yields to sell. It's a lot more effective use of equipment and labor to adjust a recipe by adjusting for brewhouse efficiency than to brew a second batch to make up the yield.

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After that it is all predetermined by simple ratios that can be applied to the adjusted mash efficiency.  That is the only thing that makes sense to me.

And, you know how to make BeerSmith do that. In other words, you will always have a predictable kettle volume, but your batch yield will be different. That's a perfectly valid way to run your brewery. Yet, if having a predictable yield into the fermenter and ultimately the keg is important, then brewhouse efficiency is going to need to be your method.

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It is just plain wrong for the program to tell you to add water to your recipe without a proportional increase in grain. 

Well, no. The brewer has made the statement that XX% of all sugars will get to the kettle with that grist. Adding or subtracting trub loss doesn't change that statement because mash efficiency is what gets adjusted to maintain the gravity. If it's diluted, then it's up to the brewer to adjust the efficiency percentage down to accommodate the additional volume or to adjust the grist. The third remedy is to adjust the batch volume down. The program doesn't assume which is correct for the brewer.

Quote
Say I want to make a batch of cookies.  I want 24 cookies so I decide to make a batch of 24 cookies worth of dough.  But I know that 4 cookies worth of dough will stick to the sides of my bowl.  So if I want to end up with 24 cookies in the oven I need 4 more cookies worth of dough. 

This example is measuring the cookie count yield to the bowl and to the oven. The bowl efficiency is 100%, but the oven efficiency is 83%. Change the cookie count to quarts, and you've illustrated brewhouse efficiency.

The difference is when you back that up to the sacks of flower and sugar. How much of THAT total potential makes it to the oven? If there is flower and sugar that can't get into the bowl to begin with, then you already have and efficiency loss from the total potential. That's what brewhouse efficiency is measuring; your sack potential.  ;D

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Since there seems to be so much disagreement on this perhaps the s/w could accommodate both sides and provide the option to [use mash efficiency].

Brad has said that the option to be mash efficiency driven is on the list of planned updates. However, updates to the numerous mobile platforms, podcasts and articles are using enough of his time that this update hasn't happened for years.

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Offline GregSalyer

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Re: Recipe batch size and trub loss
« Reply #3 on: September 01, 2018, 02:12:54 PM »
Thank you DEXMO

You stated this so well! It makes no sense to me as it is now!!!

Offline brewfun

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Re: Recipe batch size and trub loss
« Reply #4 on: September 01, 2018, 09:37:04 PM »
Thank you DEXMO

You stated this so well! It makes no sense to me as it is now!!!

The simplest explanation is: Brewhouse Efficiency is the percentage of total available sugar that gets to the fermenter.

To get in the ballpark, multiply your mash efficiency percentage by the percentage of post boil wort that gets to the fermenter (your net yield).

Example:
Expected Mash Efficiency: 75%

Post boil volume: 6 gallons.
Trub Loss/Chiller Loss: 0.75 gallons
Net wort to ferment: 5.25 gallons

5.25/6 = 87.5% net yield

Mash Efficiency % * Yield % = Brewhouse Efficiency.
0.75 * 0.875 = 65.6% Brewhouse Efficiency.

Dexmo was missing that if that percentage statement doesn't change, then the ONLY place the sugar needed to maintain gravity can come from is increased mash efficiency. That's the only way that the trub loss he added can keep the same gravity.

Eventually, BeerSmith will show mash efficiency over 100%. Of course, this isn't possible, so, you as the brewer need to adjust for it. Dexmo didn't account for the increase in trub loss being a decrease in the percentage of wort going to the fermenter.
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