What efficiencies can I expect from the G70? Nat January 23, 2023 10:38 Updated This depends a lot on your grain bill, grain crush and recipe. Our overall testing has yielded efficiencies between of 70-85%. Related articles What are the minimum and maximum grain bills that can be brewed with on the G70? G40/G70 Controller Manual Operation Features Instructions - G70 Quick Start Guide - G70 What do I clean the Grainfather brewing and fermenting vessels?