• 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.

How to set up equipment profile for partial boil?


Mar 21, 2018
Reaction score
I'm doing a series of "stove top" partial boil recipes. The idea is to brew 20L batches (20L going into the fermenter) using a 8 liter pot. Yes, I know, there are other ways to do this, but for a variety of reasons this is what I'm doing. :)

The problem is how to set up BS3 (especially the equipment profile) correctly for this method. Several posts have already asked questions on how to deal with partial boils, and I have read them, but they don't really get me to where I need to be.

In a nutshell, what I'm doing is:

[list type=decimal]
[*]In an 8 liter pot I'm putting 6 liters of water;
[*]Adding 450 gr. of dry malt extract gives me about 6.25 liters of 1.026 wort (the DME displacing about half a liter of water per kilogram when dissolved);
[*]I'm steeping 500 grams of grains in that wort (steeping in wort rather than water because the water here is incredibly hard);
[*]Removing the grains leaves me with about 5.75 liters of wort (the grain absorbs about 1 liter per kilogram) and a small gravity increase (on the order of 1-3 points, depending on the grain used);
[*]Boil this wort with hops, top up with 1 liter of boiling water halfway through the boil to make up for the 2L/hour evaporation (using boiling water so as not to interrupt the boil);
[*]Cool, let settle, strain and transfer to fermenter (loosing about 0.25 liter in the trub) so total volume transferred should be about 4.5 liters;
[*]Add 1.5kg of LME and 500 gr. of dextrose sugar to the fermenter (1.5kg of LME adds about 1 liter, 500 gr. dextrose displaces about 1/4 liter in water) and top up to 20 liters which, adding and subtracting the above figures, should take about 14.25 liters of water.

How do I get BS3 to calculate (or at least approximate) colour, bitterness and gravity for this mess? :)  Setting up an equipment profile will let me add 2L of water at the end of the boil, but if I do that I will get much less hop utilization than adding 1 liter of boiling water halfway through the boil because the boil gravity doesn't get up as high as when I only top up at the end of the boil. Then there's the diminished hop utilization due to the lower boil volume (which can be significant, trust me).

All suggestions appreciated!

// FvW