Aromatic integration is how sauces work, and why the saucier is the most important chef in a French kitchen. A great béarnaise doesn’t smell of tarragon, mint, fresh onion, and vinegar; it just smells like béarnaise. The finer the emulsion, the more surface area between the fatty beads of butter and the aqueous phase that surrounds them, so in a great sauce there can be square miles of interactive surface in a tablespoon.
