PreBoil / Post Boil Gravity

[WTexan]

Beer Smith gave me an OG of 1.063. However when I too the OG of preboil it was at 1.055 and my post boil was at 1.070. I took readings at 60 degrees.
Does any one have any ideas?

 

[fizgig]

When you boil off water, gravity goes up. Beersmith gave you a theoretical OG based on ingredients, volume and projected efficiency.

 

[RUNningonbrew]

This sounds correct, pre boil is always going to be lower because its less concentrated with sugar, your OG ended high, you could have boiled less time, collected more wort at the beginning. If your volumes are correct then you were too efficient in mashing, if that is the case adjust accordingly with your malts

 

[WTexan]

This sounds correct, pre boil is always going to be lower because its less concentrated with sugar, your OG ended high, you could have boiled less time, collected more wort at the beginning. If your volumes are correct then you were too efficient in mashing, if that is the case adjust accordingly with your malts

I'm still kinda new at all grain. So I'm trying to understand, how can I be too efficient? Is that bad?

 

[fizgig]

No it's good, Beersmith defaults to 70% efficiency, you were higher, assuming the volume was correct your efficiency was higher than 70.

Here's a good read:
http://www.howtobrew.com/section2/chapter12-5.html

 

[RUNningonbrew]

I don't use beersmith, but if it gives you a pre boil gravity I use that to estimate where my OG will be. For example if your pre boil gravity ends up too low you know you may need to boil longer to reach your OG

 

[fizgig]

Yeah, Beersmith estimates everything, post boil volume, bottling volume, various gravity measurements based on ingredients and mash temps, etc. It's pretty slick but nothing you couldn't do long hand if you wanted to.