 Evaluation of a malt or extract is usually done by the manufacturer rather than by the end user; as a rule of thumb, the total grain bill of a mash should have a diastatic power of at least 40 °L in order to guarantee efficient conversion of all the starches in the mash to sugars.The most active barley malts currently available have a diastatic activity of 110 - 160 °Lintner (385 - 520 °WK).In Europe, diastatic activity is often stated in Windisch–Kolbach units (°WK).