# Lower SG

Discussion in 'Calculator Support Forum' started by Brouwerij Nuenhem, Sep 6, 2020.

1. ### Brouwerij Nuenhem New Member

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#1
Hey,

I can't find something I need in Brwewers Friend. It seems to me that it can be found somewhere, even though here.

The following: I want to brew a beer where I only want to add hops and honey after boiling and cooling to 80 degrees. Can I find a calculation formula somewhere that calculates how much tap water (about 15 degrees) I need to use to get to this temperature and what the SG should be before I add the water?

John
Nuenen
Holland

2. ### Pricelessbrewing QA Software Tester Staff Member

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#2
This is a pretty specific scenario, but I'm not aware of any calculator or software that will do all of this at the same time.

I will need more information though, can you provide the recipe amounts/volumes for the the rest of the recipe?

You'll need to account for the PPG and volume displacement of the honey.

Mixing water together, and boiling wort can be considered water for simplification, is straightforward in metric.

1L @ 20C +5L @100C =

6L @ ((100*5 + 20*1)/(5+1)) = 86C.

3. ### Pricelessbrewing QA Software Tester Staff Member

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#3
Assuming your water is at ~20C, the water needed to cool from 100C to 80C is 1/3 of the boiling volume

(10L * 100C + 3.33L * 20C ) / (10L + 3.33L) = 80C

This is again a simplification, as the heat capacity of wort is going to be different than water, and this doesn't account for the volume addition of your honey or the fact that adding the honey will also cool it down.

4. ### Brouwerij Nuenhem New Member

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