Let’s start exploring the specificities of the whisky production. Today we are going to look at one process that is specifically Japanese.
Or at least they elevated the process into an art in such a way that it characterized Japanese whiskies today. It has of course be copied else where, this process is named…
Crystal clear wort
In the brewing and distilling industry, there are two types of wort that can be recovered after mashing: cloudy and clear. The difference between the two is as simple as it sounds; the wort liquid can either be cloudy or clear. One isn’t necessarily better, per se, but cloudy wort results in higher levels of lipids during fermentation, which adds high thresholds of nutty/cereal notes to the whisky. While there are most certainly a number of Scottish distilleries that acquire clear wort, I would say that the malty character of Scotch whisky obtained from cloudy wort is prized there. The Japanese, who only produce clear wort, offer a different take, bearing in mind cloudy wort is not the only source of nutty/cereal notes. To achieve clarity, wort can be recycled through the grain bed of the mash for further filtration or cycled through a secondary vessel known as a lauter tun. The lauter tun has a larger surface that encourages clarification of wort. The use of clear wort can change many factors in terms of fermentation, a process the Japanese value more highly than any other whisky producers in the world.
This paragraph comes from that website which I think is explaining and illustrating the idea in a very clear manner. Instead of paraphrasing, I chose to copy paste it here while acknowledging the provenance.