Manufacture of Irish malt whiskey is also very similar to scotch malt whisky, although there are some significant differences. Irish whiskey is made from a mash containing a high proportion (up to 60%) of unmalted barley . remainder of the cereal, maited barley, is not smoked over peat fire and must have a high level of enzymes. Methods of wort production and fermentation are generally similar to those used in Scotland. The use of unmalted barley however, requires the use of stone or hammer mills to obtain the correct degree of grinding. Unmalted barley is usually'sweated to raise the moisture content to ca. 14% and then dried to 4.5% moisture before grinding, but these procedures can be eliminated by use of wet milling.