The presence of dissolved starch in wort is commonly associated with incomplete saccharification during mashing, which in turn leads to a decrease in extract yield, wort fermentability and wort and beer filterability. It is therefore customary to carry out lautering at 75 to 79 degrees C, as at higher temperatures starch may dissolve out of the spent grains. However, it is pointed out that decoction mashing often involves higher temperatures in the final stages (after saccharification) so that some starch is probably dissolved, although wort and beer quality need not be impaired as a result. In fact, starch has been found in a significant number of commercial beers. High temperature lautering (at up to 95 degrees C) reduces wort viscosity, thus accelerating the runoff of the first wort (which is particularly beneficial at high first wort gravities). Sparge liquor consumption is also reduced, resulting in a lower runoff volume containing the same quantity of extract. Where runoff and the use of raking knives are controlled on the basis of pressure difference and wort turbidity, the activation of the machine is likely to be delayed and the wort is generally brighter. Although a higher lautering temperature leads to a slightly darker first wort, which could be a problem in pale lager brewing, if oxygen is carefully excluded the increase in colour intensity in the finished wort and beer should be no more than 1 EBC colour unit. In cases where dissolved starch does prove to have adverse effects on wort or beer quality, it can be treated with an amylase preparation.
Keywords : beer lautering quality temperature wort