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Trub Loss and Boil SG / Batch volumes

I really do not post often on boards, but I think I'll do an exception here.

While I do understand the geometry argument of the trub loss number and agree on the reason behind the trub loss number, it really does seems like a bug that adding more sparge water does not change the SG of the wort.

I think this is where the "bug" lies.  Where is this additional volume of water added ?  If it was added to Batch Size, then it would be accounted for in the OG calculation ( which is why I believe the fermenter loss trick works).  By adding this 2L trub loss, Beersmith adds 2L water to my sparge water, does not change the batch size, does not change the OG.

Physically, this means I add 2L water to my mix of grain and wort, definitively changing the SG of the wort.

EDIT: It does indeed change the mash efficiency when modifying the trub loss.  For a homebrewer, it feels counter-intuitive since it is not a variable we can reliably control.  Changing the grain bill does not affect the mash efficiency.  This does explain why I have been missing my OGs ever since I adjusted the trub loss.

So, what is the correct usage to account properly for loss volume ( before final wort ) and after final wort ?
 
The way that I have done it in the past is to ratio the brew house efficiency based upon the increase in water usage.  So if my total water at my normal brew house efficiency of 82% is 15 liters and I want to add another liter of trub, this means that my 'new' brew house efficiency is 82% * 15 liters / 16 liters or 76.9%.  This keeps my mash/lauter efficiency in the same range that I would expect it to run (around 87% to 88%) and adjusts the calculations to accommodate the additional water requirements.
 
Oginme said:
The way that I have done it in the past is to ratio the brew house efficiency based upon the increase in water usage.  So if my total water at my normal brew house efficiency of 82% is 15 liters and I want to add another liter of trub, this means that my 'new' brew house efficiency is 82% * 15 liters / 16 liters or 76.9%.  This keeps my mash/lauter efficiency in the same range that I would expect it to run (around 87% to 88%) and adjusts the calculations to accommodate the additional water requirements.

do you also edit the trub loss or you leave it at 0 ?

EDIT: Trub loss indeed needs to be edited for this trick to work.  Works great once you know the trick.
 
Usually, when I am making a change such as this, I am doing so in anticipation of additional trub.  Normally, I end up at 11 liters finished, 1 liter of loss to trub and chiller, 10 liters in carboy.  When I do a predominantly wheat beer with high hop loading, for instance, I increase the loss to trub and chiller to 1.5 liters in anticipation of all the added protein left in the kettle.  In this case I scale the brew house efficiency accordingly to keep my mash/lauter efficiency the same.
 
I realize I'm weighing in on a 6 year old discussion, but I just ran into this "issue" myself and I'd like to throw in my 2 cents, for whatever they are worth at this point.

I think I understand both sides.  On one hand, you have your entered BH efficiency, and Beersmith is telling you what your mash efficiency (and OG) would need to be in order to maintain that BH efficiency.  But on the other hand, I think it would be much more useful to see a realistic mash efficiency and OG target, and have Beersmith adjust your estimated BH efficiency down.

At the end of the day if I'm adding more water to my mash and boil volume, the target OG should be reduced.  I get the argument that it's a user preference issue, but I don't see myself hitting an 88% mash efficiency anytime soon.  I'd rather find out at the end of my brew that my BH efficiency was off, and correct it in my equipment settings for the next time, than spend hours pouring over my settings trying to figure out why I didn't hit my OG.

I've been using Beersmith for about a year and like it in all other ways.  It's been invaluable to my growth as a homebrewer.  But IMHO, the BH efficiency setting should not take precedence over your actual volumes and gravity targets.

At the very least, there needs to be some sort of warning with the tool tip for the trub loss setting.  Something to the effect of how it will conflict with your BH efficiency if both are not correctly entered.
 
brew shepherd said:
MaltLicker,

Thanks for the reply.  I agree that the SG of the stuff left behind in the kettle is the same as SG of the wort going to the fermenter. So, if I make a 10 gal batch and tell Beersmith 10 gallons of trub loss then the total batch is 20 gallons and the SG (OG) should be half of one with zero trub loss and a 10 gallon batch.  It doesn’t do that.  It does however change the mash efficiency to 156% so it can hold the OG.  You say to chase the efficiency so I’ll try that but something just seems off to me.
Thanks again,
Rick

I just ran into this. The trub loss is not making any sense to me! I found after a few brews that I needed to increase my trub loss and as expected it increased the amount of water, BUT my SG and Est ABV remained the same without me adding any more grain! Obviously this is not going to be the case! I see no reason my efficiency would increase due to adding more water, but that is what the software does.

More water + Same Sugar = Lower SG & ABV
 
Fundamentally, this makes sense.  The software does not work using that logic, however.  The software solves the sugar balance by having the user define the amount of sugar from the grain which makes it into the fermenter (Brew house or total efficiency).  This means that the mash efficiency floats to provide that amount of sugar from the grain bill.  If you make a change in your process losses which impact the amount of sugars that get extracted from the mash, then it is up to the user to recalculate the impact on the brew house efficiency and adjust it accordingly.

 
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