The following graph illustrates the effect of the grain weight and number of run-offs (1, 2, 3 and 4) on the lauter efficiency (called extract efficiency in the chart since this chart is from older work). As a result, the run-off amount for each sparge gets smaller as the number of sparges is increased.
Keep in mind that in all these cases the pre-boil volume is kept the same. But as the number of sparges is increased the increase in efficiency is diminishing. Subsequent sparging batches can not deliver all the extract into the boil kettle, they can only capture a part of the extract that was left behind. The more wort is held back by the grain and the lauter tun's dead space, the more extract will remain in the grains after running of. The size of the grist and/or its absorption ratio have a significant effect on the batch sparging lauter efficiency. Though it was only shown for the one-sparge case that the run-offs should be of equal size, further experiments will assume that all run-offs are of equal size even for the 2 and 3 sparge cases. But, eyeballing the volumes is just fine since slight or moderate inequalities will not lead to a significant drop in efficiency.in batch sparging the run-offs should be of equal size to achieve maximum lauter efficiency.This comes from the increased amount of wort that is left behind in the greater amount of grain and will be examined in more detail in the next section. The efficiency curve is shifted towards lower efficiency as the amount of grain increases (note that the pre boil volume is held constant and that all the curves are for single batch sparging).
This is the efficiency difference between a no-sparge and a single batch sparge. Towards the edges, where one of the run-offs comes close to or is the total boil volume, the efficiency drops by almost 10%. The experiment is repeated for 3 grist weights (10 lb, 15 lb and 20 lb).Īn efficiency optimum exists when the 1st and 2nd run-off are both half the pre-boil volume, but it is also apparent that even slightly uneven run-offs are very close to the optimum. In the E one-sparge formula this will affect V LT-1 and V LT-2. To make this experiment, batch sparging with 2 run-offs is used and the parameter that is varied is the ratio between the first run-off volume (V r-1) and the pre-boil volume (V b). Obviously this only applies to batch sparging with 1 or more sparges as there is only one run-off in no-batch sparging. The first parameter that should be examined is the effect of the relative run-off sizes. It is the sum of the run-off volumes: V b = V r-1 + V r-2.
V DG - the amount of wort left in the lauter tun after draining it equals the dead space plus the wort absorbed by the grain: V DG = V D + A * m G.A - the grain absorption ratio for wort (in gal/lb).This is the volume of water that cannot be drained from the lauter tun even if it doesn't contain any grain (in gal) V LT-n - wort volume in the mash tun before run-off step n (in gal).These are the parameters that will be important when modeling batch sparging The lauter is then drained again and added to the run-offs already in the boil kettle. More water is then added to the lauter tun which will evenly dilute the amount of wort that remained after the first run-off. The mathematical model for batch sparging assumes that all the extract is dissolved in the water volume in the lauter tun (V LT) and that this liquid is drained until only the dead space and volume absorbed by the grain remains in the lauter tun (V DG). adding another batch of sparge water will only dilute the wort left in in mash tun and not extract additional extract from the grains.after the mash has been drained, all the converted extract that remains in the mash tun is contained in water that is held back by the grain and/or the dead space of the mash tun.The closer the conversion efficiency during mashing came to 100% the less starch conversion can happen during lautering The mash is completed at the start of the lauter and no additional starches are converted during the lauter.In order to model batch sparging, two fundamental assumptions must be made: 7.1 Example: How well am I doing with my batch sparging.