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A little lost - how do i set my pot in Beersmith for a partial volume boil?


New Forum Member
Sep 7, 2013
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I usually brew from extract, with boil using grain bags. I (probably like a lot of people) use the Brewing Classic Styles (BCS) book extensively. BUT his recipes are always based on full size boil. I do a smaller boil so I can aid faster cooling with my copper coils. I know some of the 'tricks' to approximate the right IBU with a partial batch boil, but I was planning on using Beersmith to get this a little more scientific.

Thing is, I really can't work out how to set up the pot to accurately reflect the outcome.

Ideally I want to set up a pot roughly like this:

10 litres pre-boil
total batch size into fermenter around 19 litres

I can see that the likely things I need to adjust are: Boil Volume, Boil Time, Boil Off, and the Batch Volume.

I assume if my Boil Volume was (for example) 10 litres, with a total Batch Volume of 19 Litres, that provided I uncheck Calculate Boil Vol Automatically and enter 10 litres in and adjust my Boil Off, the software can work out that this means i'd be adding water as a top up and will adjust accordingly?

I assume that also means I need to do a calculation manually of my boil off if I want a good level of accuracy as I can't check calculate automatically as it assumes a full size boil.


Grandmaster Brewer
Sep 6, 2011
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Ventura, CA
Equipment profiles should reflect the volume and circumstances of the brewing session. So, it's best to have a partial volume profile in addition to the full volume version.

The other factor is Brewhouse Efficiency. If the trub losses are the same (i.e.: no matter what size batch, you'll always have 1.5 gallons left in the kettle), then the efficiency has to be adjusted downward to reflect the fact that the loss represents a larger percentage of the actual batch.

The advantage of having multiple profiles is that you can take recipes of either size and quickly scale them up or down as needed.

I have separate profiles for partial batches and for larger hop loss recipes. It saves a lot of time and aggravation.


Grandmaster Brewer
Mar 16, 2013
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New Hampshire, US
In your equipment profile, you can set to 'top off' with water into the fermenter.  This will subtract this amount of water from your initial amount required for steeping grains and extract.  I would make a separate equipment profile to work with until you get the balance of top off water to fit your process.