For the first batch, Master of Malt recommends to fill your cask with something other than expensive whisky. This is because the cask has never been used before, and the wood is still packed full of flavours that are ready to overwhelm any liquid you place inside it. For this purpose, I decided to use Bols Corenwyn, as this resembles unaged whisky spirit fairly closely.
The first batch uses Bols Corenwyn
Korenwijn (Bols uses the Corenwyn spelling to make their product seem that little bit more fancy) is a type of Dutch jenever. It literally translates to ‘grain wine’, and to an extent it is just that. By regulation, korenwijn must contain at least 51% malt wine, meaning that like a whisky, malted barley is its main ingredient. To contrast, ‘jonge’ jenever may contain no more than 15% malt wine, while ‘oude’ jenever must have at least 15%. As such, korenwijn is often seen as the more luxurious cousin of jenever, and indeed is often cask-aged before being bottled. Korenwijn is distilled to a strength of about 50% alcohol and bottled at a standard 38%. Distillation to such a low alcohol percentage leaves a lot of space for impurities, and these are traditionally masked by the addition of herbs. The botanical of choice is typically juniper, from which the name jenever derives.