Four of the innumerable oceans are not water. This is the first of them: its taste is that of vāruṇī, liquor. Beyond it lie an ocean of milk, an ocean of clarified butter and an ocean of sugarcane juice, in that order.
The four are not an ornament. They are how the cosmology marks the rings that have a character of their own, against the innumerable others that are simply water and are named and counted and nothing more.
The middle world, ring by ring - Vāruṇoda highlighted