Calculating extract gravity units.

When calculating GU's for a certain amount of extract, do you apply an efficiency factor?

Say you have 3 pounds of DME. Assuming an extract potential of 1.045, would you be getting (3 x 45) = 135 GUs? Or would you have to factor in the efficiency of your brewhouse (say 70% or so) meaning the equation would be (3 x 45 x .7) = 94.5 GUs?

Thanks!
-Kelly

For dry and liquid malt extracts, you do not have to factor your brewhouse efficiency into the equation. You aren't converting any starches to sugars, the maltster who made the extract already did that. The amount of gravity added by these extracts is a fixed number (relative to the volume of water and amount of extract of course).

Brewhouse efficiency only comes into play when you are mashing and converting grain starches into sugars.