Think about how a favorite recipe stays the same, generation after generation. Moab's 'flavor' was stubbornly intact, but not necessarily for the better.
The imagery of wine tasting and smelling the same comes from its undisturbed state.
The Unchanged 'Flavor'
- "His taste remains in him, and his scent is not changed." This refers to Moab's national character. Because they hadn't experienced the jarring process of being 'emptied from vessel to vessel' (like wine being transferred to settle its lees), their distinct national character, their habits, and their sins remained unchanged.
This wasn't necessarily a positive thing. While it meant their identity was strong, it also meant their pride, their idolatry, and their opposition to God likely persisted without the humbling effect that discipline and exile can bring.