Distillery is a gulp project to build an output cucumber testing solution by bundling features, worlds, steps and related files from multiple sources.
This allows separating the features of your site from the implementation, thereby creating a true cross site collection of terms. This could have been done by restructuring how Cucumber works, but it seems easier to build on top of cucumber by making this bundling solution.
The choice of the name distillery is because of distilled vinegar being used for pickling, and nowadays it seems incumbent on people to use somewhat punnish names constructed on a related theme for any solution.