Pre- and post-boil gravity discrepancy

[mrskittle]

I'm working on learning all the tools that the recipe builder has and am getting better. One thing that I'm not sure about is the predicted, post-boil gravity that it gives. I've come pretty close to the predicted pre-boil numbers but never the post-boil. I looked through a few of my recipes and the builder predicts around a 15 point drop due to the boil but I've never gotten more than and 10 pt drop. For example, I'm shooting for a pre-boil gravity of 1.048. While the recipe builder says I should see a post-boil gravity of 1.062+, I'm looking at no higher than 1.058.

Is there a way to enter the typical gravity drop that I get with my equipment instead of getting an estimate?

 

[Megary]

The easiest thing to do is drop your efficiency value. If you are building recipes based on 70%, then just change it to 65. You will likely then overshoot your Pre-boil gravity and hit your Post-boil, all at the cost of a few more ounces of grain. Over time, if your efficiency changes, you can always adjust again.

FWIW, I never pick up as many points in the boil as the calculator expects either.

 

[Pricelessbrewing]

If your hitting the preboil gravity, than your mash efficiency is accurate.

If your postboil gravity is no longer accurate, than either the brewhouse efficiency is not input correctly, or some combination of the preboil volume or postboil volume is off. Mathematically it's impossible to hit the preboil volume, preboil gravity, and postboil volume and NOT hit the expected OG.