Once you’re done with sugaring, it’s time to rinse the mash with hot water (78 °C). The quantity of water depends on the recipe, but usually it’s around 3-4 liters of water per each kilogram of malt. In the very beginning you start by draining out several liters (the haziest) and bringing them back in the mash. Then you start rinsing the mixture with “sparge” water and collecting the drained sugary substance (called wort), which you are about to boil later.
The lautering process is usually not a fast one due to the speed at which the mash is being filtered. Nevertheless, it should not be carried out for too long, since the temperature of the malt must be kept above 60 °C. On the other hand, if you rush it too much you would not extract the sugars optimally from the malt. It’s normal to take at least 20-30 minutes, sometimes up to an hour or more.
The speed of lautering depends mainly on the equipment used and somewhat on how well the malt was milled (more info on that here). Some of the popular technical solutions include a stainer, a vessel with fake bottom, a hose with holes, two buckets – one in the other, where the upper one has holes drilled on its bottom and the lower one has a valve on the side of its bottom. Whatever strategy and tools you choose, do not forget that you should make it fast enough to keep the mash temperature above 60 °C and keep the malt watered (not to let it dry out).