Linked from
The 10 pages that link to Steam, each with the reason it gives.
Deep fryingRelated: Moisture escaping as steam helps limit oil entry while food cooks.
FlatbreadRelated: Steam trapped inside some doughs can separate layers or inflate a pocket.
BatterRelated: Water escaping from batter can create a light, porous coating.
Coal gasificationRelated: Steam reacts with hot carbon to produce hydrogen and carbon monoxide.
Apple pieRelated: Moisture from the filling becomes steam and can escape through vents in the crust.
ChapatiRelated: Water trapped inside the dough can turn to steam and puff a chapati during cooking.