Historically, crushing grapes was done
by feet in 'lagares', or shallow stone or
cement troughs. Amazingly, in the
Douro, some grapes are still trodden by
human feet. The human foot is ideally suited to crushing grapes.
Treading breaks the grapes, crushes the skins, then
mixes skins with juices for good flavor and color
extraction--all without smashing the pips (seeds), which
contain bitter tasting tanins.