If our measured pre-boil gravity is 1.060, then our mash efficiency is calculated in this way: 60 / 79.2 = 75.8% Suppose we mash the following grain bill and end up with 5 gallons of wort: As a result, calculations become a little more complicated.
The challenging part of calculating mash efficiency is that we tend to brew with multiple types of malts, often with different extract ratings. We simply divide the measured gravity by the potential gravity to calculate the mash efficiency: The typical mash efficiency of a homebrewer will be in the ballpark of 60-80%, though this number can vary quite a bit depending on the brew, the type of homebrewing equipment being used, and number of other factors.Ĭontinuing with the example above, suppose that the actual measured gravity of the wort when taken by a hydrometer is 1.050. Divide by 5 gallons, and the resulting pre-boil gravity would have 74 points per gallon, or a gravity of 1.074.īut even the most efficient mashing processes can’t extract all of the sugars from the malt. If we were to extract all of the sugars from that malt (achieving 100% efficiency), the resulting wort would have a total of 370 points (37 points * 10 pounds). After the mash and the sparge, we end up with 5 gallons of wort. Suppose that we use 10 pounds of two-row malt in a mash, and that this malt has a gravity rating of 1.037, or 37 points. Later we’ll get into improving mash efficiency, but for now, here is one method for calculating mash efficiency, by using the gravity measurement of points per gallon (PPG): By improving mash efficiency, one can use less malt and save a little money, but the real value for the homebrewer is the ability to accurately predict the amount of malt needed when formulating a beer recipe. Brewing malt contains a certain amount of complex sugars, and the percentage which are extracted in a mash give us the mash efficiency. Mash efficiency is a measurement of the percent of available sugars obtained through the mashing process.
(5 × 2.7) + 3.5 = 17L mash water Make up the difference in the sparge Because the RoboBrew and Grainfather have very similar dimensions, the physics of the recirculating mash are very similar. Instructions for the Grainfather use a slightly more complicated formula. For every kilogram of grain, add three litres of water:įor a typical 5kg grain bill this means 15L of water for your mash in.ĥ × 3 = 15Lmash water The Grainfather formula When recirculating, the trick is to have a nice liquid mash without the weight of the water and grain pressing down on the malt pipe screens hard enough to cause blockages. Dedicated brewers will spend years fine-tuning their mash-in water volume and grain crush to get optimal efficiency and clarify, but for most Robobrewers purchasing pre-milled grain from a local homebrew supplier, there’s a few formulae that will give you great efficiency and reduce the chances of a stuck sparge right off the bat.