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Volume left in kettle after transferring to fermenter


Oct 6, 2016
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So I tried to elicit an answer to this earlier and I don't think I communicated the question well so I'm going to try again.

Before I phrase my question, I think this is pertinent:  If I don't compensate for this loss in BeerSmith, my targeted gravities are being hit with consistency and my target volumes are also being hit with consistency along the way (pre and post boil, post cooling) with the exception of final batch volume or wort in the fermenter.

The volume I am trying to plug in to BeerSmith is the 0.4 gallons of wort leftover in the kettle after cooling and transferring the wort to a fermenter.

I attempted to adjust this using "Loss to Trub and Chiller" but when I did this the only value that changed in the recipe was the starting full boil volume and the only metrics that changed were color and IBU's, not OG.  However, when I followed the recipe I ended up with an almost equivalent amount of extra wort (0.5 gal) and the OG was severely missed (Meas 1.030, Target 1.056) When I removed the Trub and Chiller Loss adjustment it lowered my initial water volume needed and as a result, both the target post-cool volume and target OG were reached.  (Also pertinent, when I did this particular brew, it was a small volume, 1 gallon target, 1/5 gal measured, which explains the really large OG discrepancy, but even at full volume brews it still significantly misses gravities when used as described)

The question is: Do I plug in this leftover volume of Kettle deadspace in BS, and if so, where? or do I just compensate with increasing my batch volume by 0.4 gal to maintain target gravities?


Grandmaster Brewer
Mar 16, 2013
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New Hampshire, US
Add the 0.4 gal left in your kettle to the 'loss to trub and chiller'.  Now go back and adjust your brew house efficiency (total efficiency) to bring your numbers back to where you measured them for the brew. 

Beersmith works by setting the volume to the fermentor as a fixed variable.  It them back calculates the numbers from there to reach the OG from there.  When you add 0.4 gallons to the loss to trub and chiller, Beersmith 'fixes' your problem by increasing the amount of water needed and the mash efficiency to compensate for the sugars lost in the wort IN ORDER TO MAINTAIN THE TARGET OG. 

If you started with a set volume of water recommended by BeerSmith and finished with 0.4 gallons above your target volume into the fermentor, then you also need to measure and change the water loss to grain absorption and/or your boil off rate to bring the estimated water back into balance with your actual results.