Why is white sugar so much easier to store and ship than brown sugar?

Why is white sugar so much easier to store and ship than brown sugar?
Refined white sugar is essentially pure crystalline sucrose, so it does not spoil. Its main storage risks are caking from hygroscopic moisture uptake and odor absorption due to porosity, both manageable with sealed packaging. Brown, black and molasses-containing sugars carry moisture, minerals and vitamins that support microbial growth, giving them defined shelf lives of up to 24 months and rapid flavor loss once opened. Historically this durability made white sugar the only grade viable for long ocean voyages, and it remains the reason refined sugar dominates trade flows while specialty brown grades stay regional and short-cycle.