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Molasses. The usual practice is to place a quantity of "Rice Tailings" (the residue left in the still after the distillation of Rice Spirit) in a large earthenware jar or Kong. To this fixed proportions of Molasses and Water (warm in cold weather) are added and also a small quantity of fermenting Molasses Mash. The latter plays the part of a Mother Ferment and its use enables fermentation to commence rapidly. The contents of the Kong are then thoroughly mixed and within six hours fermentation will have commenced and at the expiration of 24 hours there will be a brisk liberation of bubbles of carbon dioxide gas through a thick scum of yeast on the top of the fermenting liquid. During fermentation (as in the case of Rice) a slight rise in the temperature of the fermenting liquid takes place. At the end of 12 to 24 hours (the actual time period varies at each distillery) a second and final portion of Molasses is added to the Kong and the liquid is again well stirred up. This stirring is continued twice daily for the period of fermentation which varies from 96 hours to 120 hours according to the season of the year. It was found during the year that fermentation of Molasses proceeded normally if all the Molasses was placed in the Kong at one time instead of in two portions as shown above. A small quantity of fat is often added to the Kong of fermenting material to avoid excessive frothing due to too rapid fermentation. This fat prevents the formation of large bubbles of scum on the top of the liquid and consequent overflow of the contents of the Kong. As the result of Laboratory Control during the year it was found the Rice Tailings were added on account of the fact that the nitrogenous matter in the Tailings were essential for the life of the yeast which converts the sugar of the molasses into alcohol. Experiments were carried out using Ammonium Sulphate as the source of nitrogenous matter and it was found possible to omit the Rice Tailings and ferment Molasses with a Mother fermenting liquid and a small quantity of Ammonium Sulphate. This method was adopted during the year by two distilleries and the yield of Alcohol per unit of Molasses was found to be excellent. This was an important change, as in the past all distilleries had been compelled to make sufficient Rice Spirit to provide Rice Tailings for the fermentation of their Molasses. The high cost of Rice made Rice Tailings an expensive aid to fermentation unless a good market could be found for the Rice Spirit produced.
5.-Output of Alcohol compared with the amount of Fermentable Material used.
Rice using Ball Yeast. It was found that in the small country distilleries the usual practice was to use three jars of fermented rice (the equivalent of 24 to 27 catties of dry Rice) as a charge for a still. From this one four-gallon jar of 21% to 22% spirit was distilled.
Rice using Cake Yeast.--The distilleries using this type of yeast place the same equivalent of dry Rice in each jar but usually distil one four-gallon jar of spirit from four jars of fermented rice. This spirit varies in strength from 28% to 32%.