The Spiorad na Bainne, literally Spirit of the Milk, is a fermented milk drink from the City of Launceston at the Icy Shore. It is mostly produced either from cow milk or sheep milk, animals, which play an important economic role in the area. Several other areas, like Shella, produce their own Spiorad na Bainne.
Both cows and sheep don't produce a milk with a high lactose or sugar content, which means, that the milk must be fortified before production. The most often used variant of that is adding Sucrose or table sugar from various sources, while the more high-quality brands add modified whey, the liquid left over once milk has curdled (for example after cheese production).
Some brands also made the Spiorad na Bainne with horse milk, which is actually easier as it already has the right amount of sugar.
The resulting spirit has 0.7 to 3 percent alcohol content with a slightly sour taste and a bit of a bite due to the alcoholic content.