Efficiency is a figure used to describe how much of the potential sugars from the fermentables were extracted into your wort, typically given as a percentage.
- Mash efficiency only takes into account how much of this sugar was extracted during the mash. the calculation is done after sparging.
- Brewhouse efficiency takes into account losses such as; boil off, trub and transfer losses, all of which affect your fermentation volume.
In this way, Brewhouse efficiency is a measure of the overall efficiency of your brew house system.