The extract is defined by the set of matters dissolving themselves during brewing.
In order to measure the extracts output:
- a conventional brassin on the fine mouture is made
- then the wort density is measured with the help of a saccharimeter of Plato
- reading is in Plato degrees, which expresses the concentration in grs. of extract for 100 grs. of wort
For 2RS barley the output is between 80 and 83 (on dry matters), it is necessary to count 1 to 1,5 in less for 2RW and 6RW malts.