yield
From The Oxford Companion to Beer
is a measure of the amount of a raw material that survives a process as a percentage of the amount of that same raw material used as input into that process. Two important yields that brewers are concerned with are brewing material efficiency (BME) and hop utilization.
Downstream from the brewhouse, yield is often measured in terms of beer loss, which is often expressed in terms of extract rather than raw volume losses, because this removes the variable of concentration and/or dilution from the equation. In most breweries, beer losses are measured and tracked for each step of the beer-making process, rather than simply as the amount brewed versus the amount packaged. At the packaging line, too, yield is measured as beer loss.
Bibliography
This definition is from The Oxford Companion to Beer, edited by Garrett Oliver. © Oxford University Press 2012.