Beersmith 2 cooling shrinkage bug

I've discovered a problem with beersmith in that it changes anticipated gravity with the default 4% cooling volume shrinkage. To see what I mean go to the boiloff tool, and compare the finishing gravity with 4% shrinkage to 0% shrinkage.
The anticipated gravity changes if you put in ANY shrinkage. This doesn't make sense. Its like it expects you to read your gravity without any temperature correction.

Is this a real bug or am I misinterpreting something? Should I report this to the BS people? Its a major problem because it changes my recipes by .003 or more. The beer doesn't lose sugars when it cools does it??

Subscribed, patiently awaiting answer!

Budzu said:

The beer doesn't lose sugars when it cools does it??

Click to expand...

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.

Yep that makes sense now!... what made it confusing for me is measuring my post boil volume hot with a dip stick, then taking a corrected, chilled gravity. I did not incorporate that cooling shrinkage properly. (my volume was unshrunk, and my gravity sample was chilled.)
Good thing beersmith does the math for me. Now to just calibrate everything right... brewing 4 gallon batches makes errors magnify (I usually brew 2 bbl's).

it shrinks???? I WAS IN THE POOL!!!!!!!!!!!!!!!

now that's funnay