
Nutmeg is a warm, aromatic spice — the seed of a tropical tree — grated to powder just before use.
Mace is the same tree and a lighter, more perfumed version of the same aroma. Pre-ground nutmeg works and is a shadow of the fresh grating, since the oil starts leaving the moment the seed is opened. Cinnamon with a little clove covers the warm-spice role and fools nobody.
Mace
The lacy red aril around the same seed, dried separately. It is finer and more floral, and it costs more — which is why bars keep nutmeg. Grated over a flip it reads lighter and less warming.
Pre-ground nutmeg
Convenient and much weaker, since grinding released the oil into the air long before the jar was opened, and use more of it and expect less.
Whole nutmegs keep for years in a sealed jar and stay potent because the oil is locked inside the seed. Ground nutmeg is finished within months. Buy whole, keep a grater beside the jar, and the difference is obvious in the glass.