If you have ever received moringa powder that was more khaki than green, you have seen the result of sun drying. It is faster and cheaper, and it destroys exactly the properties buyers are paying for.
What direct sun does
Ultraviolet exposure degrades chlorophyll and oxidises the vitamins and polyphenols that give leaf products their value. The colour loss is simply the visible symptom of a chemical one.
Shade drying in practice
Leaf is spread thinly on racks in ventilated sheds, turned regularly and dried over two to three days rather than a few hours. It needs more space, more handling and more time – and it delivers a deep green powder with the aroma intact.
Milling temperature matters too
Careful drying can still be undone at the mill. High-speed grinding generates heat, so we mill in stages with cooling between passes, which keeps the powder below the threshold where volatile compounds start to escape.
What to ask your supplier
Ask how the leaf was dried, how long it took, and what the milling temperature was. A supplier who cannot answer is buying from the open market and reselling – which may be fine for your application, but you should know it.
For mint the same logic applies, with the added point that tea-cut material must be cut after drying, not before, or the aroma leaves with the dust.