The malt when ready for manufacture is ground to a coarse powder and placed in a mash tub. Here it is mixed with enough water to bring it to a proper consistency, and the temperature is raised so that the maltose and any remaining starch present is made into a jelly, and the remaining starch converted into sugar by the action of the diastase. Water which has come from peaty marshes is considered of superior quality for mixing with the ground malt to make the mash. The mash tub is usually quite large and supplied with a stirring apparatus driven by machinery whereby all parts of the mash are kept thoroughly mixed. The bottom of the mash tub is double; the first bottom being full of fine perforations, and the second a closed bottom. The object of this is to draw off the liquid portions of the mash, leaving the bran and undissolved portions on the upper bottom where they can be removed and used for cattle feed, or other purposes. The temperature of the mash tub usually is not allowed to go over 140°F., since at higher temperatures the diastase would not convert any remaining starch. After all the starch is converted the mash can be raised to a higher temperature, if desired. The liquid maltose and other sugars are now called the wort, and it is drawn off from the mash tubs, cooled and run into the fermentation vats. After the wort is cooled to a proper temperature, the yeast is added and the fermentation begins. It requires from 48 to 72 hours to complete the fermentation and convert all the sugar into alcohol. The fermented wort is now beer.