The bain-marie or double bolier still

As the name implies, this still uses the very old bain-marie or double boiler method, taking its name from the invention attributed to the alchemist Maria Giudea, traditionally identified with Myriam, the sister of Moses.

In this case, the boiler has a double wall; in the interspace there is steam or very hot water which heats the marc placed inside the boiler. The ethyl alcohol and the substances contained in the marc evaporate, pass through distillation column and are then condensed into a coil. Cutting of the heads and tails also occurs here. 

This still is very widely used, especially in the Trentino and Upper Adige regions, and ensures a very gentle extraction of the marc aromas. 
It is commonly used to distil fruit and grapes 
alambicchi-bagnomaria-grappa