Extra-dark vs dark chocolate

Above roughly 85% the trade-offs change character: less sugar means less to mask defects, and less to hold the texture together.

Side by side

	Extra-dark (85%+)	Dark (60–80%)	Why it matters
Room for defects	Almost none. Sugar is what masks harshness, and there is very little of it.	Meaningful. 70% is forgiving of moderately variable beans.	A bad 90% is much worse than a bad 70%. High percentage raises the floor required of the beans rather than guaranteeing quality.
Aromatic expression	Often narrower. Very high cocoa content tends to flatten fine origin character rather than reveal it.	Usually the range where origin character is most legible.	Most makers put their best beans at 70%, not at 90%. Percentage is a formulation choice, not a quality scale.
Texture	Drier and more crumbly; sugar contributes structure as well as sweetness.	Smoother, with more give.
Baking behaviour	Less sugar, so recipes need adjustment.	What most recipes assume.	Substituting 90% for 70% in a recipe removes sugar and adds cocoa solid, changing both sweetness and moisture absorption.

When you specifically want intensity and minimal sweetness, and you have a maker you trust — the format is unforgiving.

For almost everything else, including tasting, baking and pairing. It is where the craft chocolate industry does most of its best work.

Extra dark chocolateSet against Dark (60–80%), with the practical consequence of each difference.
Dark chocolateSet against Extra-dark (85%+), with the practical consequence of each difference.

ChocolateHQ editorial synthesis — ChocolateHQ(citation identity confirmed; passage not re-read)