Portuguese name (Spanish Lago) for the flat trough made of granite stone, concrete or stainless steel in which the mash fermentation for the production of port wine is traditionally carried out. In some cases, the grapes are still crushed in these troughs with stalks or bare feet to break up the berries for better extraction of the colourings and tannins. The rammers stand with their arms hooked in a row and march slowly back and forth in the trough for up to two hours. The human foot is strong enough to crush the grape, but not so hard and unyielding that the grape seed bursts open. The bitter tanning agents contained in the seeds are undesirable. See also under vinification and wine vessels.