Picked basil today to dry. I washed it and noticed about an hour after picking that it is turn black--it isn't mold or mildew tho. Is it supposed to turn black so quickly? The day is cool and low humidity.
Yep, basil will turn black when exposed to water,
Basil doesn't turn black when exposed to water (unless, perhaps, it's extremely cold), but may do so if handled less than gently.
Basil will turn black when roughly chopped, and sometimes when frozen while still wet. Solution - blanch and allow and pat dry before freezing.
BTW, the flavour is NOT affected by the change in colour.