The mashing was done usually by hand in tubs prepared for that purpose. The mashes consisted of small quantities and they were mixed and manipulated with a paddle. In order to get a sufficient degree of lactic acid ferments each new mash was mixed with a considerable quantity of hot slop from the previous distillation, hence the term "sour mash" which still persists in many quarters. After scalding and cooling to a proper temperature, the conversion of the starch was obtained in the usual way by the addition of malt. Other grains, however, than barley were malted for this purpose and it was not unusual to malt the corn itself, at least partially, before the conversion process of the starch into sugar was accomplished. Initial fermentations of the mash were of course secured by the addition of ordinary yeast, the kind of yeast that was used for making bread being very commonly employed. After the distillery was once in operation, however, yeasts were skimmed from the preceding fermentation tanks and this form of yeast was commonly called "barm." After fermentation was completed in the fermentation tubs, the beer was carried by buckets and poured directly into the still. The copper still was often made in two pieces so that it could be taken apart and be filled up in this way by buckets. The stills were universally made of copper and were heated directly over a wood fire. They were not large and the rate of distillation was irregular. From the very first, however, it was found that the first distillation did not make a spirit of sufficient strength and therefore this spirit, after the first distillation, was put back into the same still and doubled. This doubling was supposed to have two effects, first, it brought the alcoholic content up to proof, or sometimes above, and in the second place it eliminated certain quantities of the gross materials which were carried over in the vapors of the first fermentation, thus improving the quality of the finished product. This doubling, however, did not appreciably diminish any of the important constituents which go to distinguish whisky from ordinary neutral spirits. After the distillation was completed the still was opened and cleaned. Naturally quite a quantity of the mashed grains not worked up into alcohol would find their way into the still. These deposits, settling on the bottom of the still, would protect the still from direct contact with the liquid contents and the result would be that often these deposits would be burned, giving in this case a scorched taste to the whisky.