Very crisp, black, straight lines (4-3)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

B (abbreviation for black) + ONE-D (abbreviation for one-dimensional = in a straight line = straight) + RY (abbreviation for railway = lines). I’m not quite convinced by 1-D = straight, but I assume that’s what’s intended. Very crisp = bone-dry = descriptive of white wine without much residual sugar. Or perhaps just meaning something with all the moisture removed.