Why did I get a low starch to sugar conversion? This could be due to a few factors;Incorrect grain crushDiastatic properties of the grain billIncorrect mash temperatureWrong mash timeIncorrect mash water pHIncorrect mash water calculationsMash thickness Related articles How can I improve my efficiency? Is the 'batch volume' the final, end amount I'll finish up with? What is BU/GU? I have a lot of foam forming during the boil, is this normal?