Originally Posted by Budzu
The beer doesn't lose sugars when it cools does it??
No. It "gains" sugar.
Here are my settings -
Starting vol - 6
SG - 1.050
Evap - 10%
Boiltime - 60
With Shrinkage = 0 the Post Boil Gravity = 1.056
With Shrinkage set to 4 = 1.058
That is the correct behavior. Let's say you have a pound of sugars in there. If you have 0 shrinkage, you have 5.4 gallons. But when you put in 4% shrinkage, your volume drops to 5.18 gallons.
So, you've still got the same amount of sugar in a smaller volume of water, therefore you get a higher gravity.