Feature request: Add support for Plato and Brix as an alternative unit of measurement for fermentation.

[fkroepfl]

Reference: /settings/#tiltbridge

Getting used to other units of measurement is not quite so wild, but if you are working with Plato, for example, it is convenient to have the correct result already displayed straight away 😉.

[thorrak]

I'm in the process of doing a UI overhaul ahead of Fermentrack 2 gravity support. I'll see what I can do.