>>18090135
>a surname applied to those who resided near a Hiedl (“subterranean river”) (Bavarian dialect). Earlier theories derived the surname from Hüttler (also spelled Huettler), either meaning "one who lives in a hut", from Hütte (“hut”)

The funny thing is that the first etymology implies that they lived near/in dolmens/caves, which was the place that the Germans used to ferment beer and where the Witches' Sabbats took place in the Alps.