Folks commonly use the words “grass” and “spice” interchangeably, but they actually are two different kinds of seasonings. They come from different parts of plants and you process them in various ways. Both serve to give taste and aroma to the food.
Salt is neither grass nor spice, but a mineral
Herbs and Spices: What Is the Difference?
Grass is the leafy, green part of plant. Examples are basil, rosemary, sage, thyme, parsley and oregano. You use those leaves from shrubs for aroma dishes, and although you commonly use them dried, fresh grasses are best.
Spices instead can come from the root, stem, seed, fruit, flower or bark of tree or plant. Spices are dried seeds, roots or other plant parts, that you add for taste and color. Almost always you use spices in dry form.
Some plants can be both grass and spice. For instance, coriander seeds are spice, but the leaves of the same plant are the grass cilantro. Likewise happens with dill and fennel: the leaf is grass, but the seed is spice.
For bright and tender taste, you commonly use fresh grasses. Dried grasses focus the taste, but they are widely gentler than the fresh versions. They are popular for ending dishes, in salads, sauces and garnishes.
Spices you can add any time, but most commonly you lay them early at the start of the cook.
Dry spices are good, but toasted spices are better, and bloomed spices are wonderful. This proccess, also called “tempering“, is a simple step to cook the spices in oil to extract the maximum taste and aroma.
The main goal is not to rule the food, but improve its taste. For a dish for four or six people, a good start is half a teaspoon of spice. It is a clever way to add only one grass or spice at a time during the cook.
Strong tastes, that can dominate, include bay leaf, cardamom, ginger, pepper, mustard, rosemary and sage. If you keep dried grasses and spices in closed tins, they will last years.
All along human history, you used grasses and spices to make the food more delicious. The Ebers Papyrus is an Egyptian scroll that lists plants used as medicines, and it dates back to around 1550 BC. Among the listed spices are anise, mustard, saffron, cinnamon and cassia.
Centuries ago, folks travelled for months through land and sea to get certain spices, that became incredibly precious.