Hijacking details from the brewing process is a common way to develop a campaign for your liquid product. For example Crown Lager is basically Carlton Draught that stays in the barrel for longer (thereabouts). Their line was “Time is the fifth ingredient.”
I think the art direction for this ‘made in the dark’ extension for Magners is rock solid. There’s nothing like making the product stand out by dropping the background completely. But why do they brew it in the dark?