Gravity/dilution Math question

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imperialipa

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Any excel buffs out there?

There is a formula I would like to plug into excel which will have different X variables.

I am dialing in my wort volume and Preboil gravity for my system but until I nail it I have had cases where my efficency was too high or too low. I use beersmith but dont see anything that specifically addresses DME effect on wort (if you under gravity) and water dilution on wort (if your over gravity)

Example Had 7 gallons @ 1.082 and was supposed to have 1.065 pre boil. How much water to add to get it down to 1.065

C1V1 = C2V2

C concentration (points of gravity)
V is volume

C1=82
V1=7
C2=65
V2=x

82x7=65xX
574=65x
574/65= 8.83 gallons total

I would then do my normal boil and just end up with more wort than the anticipated 5.5 Gallons but at the correct gravity.

I believe this formula can be used to adjust your IBU's also.
 
How about this
Enter Target gravity: [A1]
Enter Actual gravity: [A2]
Enter Actual volume: [A3]
Volume to add: [=(1000-1000*A2)/(1000-1000*A1)*A3 - A3]
DME to add: [=1000*(A1-A2)*A3/44]
 
That seems to work great!

The figure for the DME it gives would be in lbs right?

I plugged in 1.050 to the Pre-boil Target gravity figure
1.040 to the actual pre boil gravity figure
7 for the volume. (assuming 7 gallons of wort were collected)
and it gave me 1.59 for DME

So if I'm understanding this math correct it would take 1.59 lbs of DME to bump 7 gallons of wort from 1.040 to 1.050.

It also said neg 1.4 for water. So I could boil off 1.4 gallons to achieve the same effect.

Math is not my strong point for sure. Unfortunately brewing seems to have alot in it!

I wonder if there would be a way to integrate the hop changes needed into the formula.
 
yup the DME is in lbs. if you want, you can switch it to LME by using 36 instead of 44, or sucrose by using 46, etc.

just remember, the water addition only works if you still boil the same amount of time. if you boil it longer to get to the original intended volume, then the adjustment is null. but you could just apply it to post-boil in that case. actually, both water adjustments kinda work better for post-boil.

as for the hops, if you're adding DME then no adjustment is needed cuz you'd be at the intended gravity. if you're changing the water volume, then it depends on whether you boil it the same length or not. that ones quite a bit more complicated either way you go about it. either way it only effects you're bittering add and unless you really screw up, it shouldnt be much of a change
 
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