– Mash efficiency:
Brewery is the result of a chemical process, of transformation of starches into sugars. For each malt we use, we know exactly its potential, that is the quantity of theoretical sugars, which we can extract.
So we have a certain amount of starches, which thanks to a certain amount of enzymes, appropriately activated by temperature, and a congenial environment (ph wort), are transformed into sugars.
From here we understand that in order to have a correct conversion of starches into sugars certain conditions must be respected, the closer we are to the ideal conditions, the greater the efficiency of the mash, or the amount of sugar that we can extract from the malt.
The efficiency of the mash is expressed in%
The percentage of efficiency of the mash depends therefore on many factors,
the facility
the technique
the accuracy of measuring instruments
our precision and ability.

myadv
The Mash efficiency is a value that is at the base of the calculations for the design of a beer, in fact, with the same recipe, the results in terms of OG (Original Gravity), or the initial gravity of the wort can be very different from cooked to cooked .
If we want our calculations to be accurate, we need to know what our mash efficiency is.
In the case of your first beer, keep on average values ​​of 65% 70%, in the subsequent batches you can double check this value and change it.

– Dilution of grains:
the amount of water that will be used for each kg of malt in grains that we will use in the mash must be indicated.
Normally this quantity varies according to the technique used:
therefore, if you use the Allgrain Classic method, you must indicate 3 or 3.5 l / kg
if you are brewing with the E + G method you can indicate values ​​of type 5 or 6 l / kg, while if you were proceeding with the BIAB method this value is completely ignored because a different calculation is performed for the BIAB method.

– Grain absorption:
It represents one of the many losses that occur in the brewing phase, or the amount of liquid that will be retained by the grains after the mash.
The more precise we will be to specify the losses of our system the more precise the result of the app calculations will be.
Generally this value is between 0.8 and 1.2 l / kg
It all depends on how much and if we will drain / squeeze the sores after the mash.

– Loss in Mash:
What are the losses of mash, for example in the case of using a pot with tap, obviously it will be impossible to fish all the liquid to the end, also because it will be full of flour that obviously should not be brought into the wort.
In this field it is therefore possible to enter this value expressed in liters.