How do spices work?
It is now the time of year most firmly associated with dark spices. You know those of which I speak, the oily powders we keep hidden away through the summer only to find perpetually at our side as the days grow shorter. Perhaps, originally, we turned to these flavors in the colder months simply because the greenery that we so favored in our foods withered with the changing temperatures. But the reason we keep coming back to them is precisely because they are so powerful. A little goes a long way, so they say, and indeed the adage stands true. Not much more than a whiff of nutmeg is necessary to transport me back in time to the scents of winters past. These are the spices that keep our hearts smoldering like coals through wind and snow.
But what is a spice? And how is it different from a herb? Some define herbs as the things that grow in a native garden, while spices are considered the exotic flavors found abroad. To others, herbs are the leaves, stems, and general greenery, while spices come from the roots, seeds, and nuts of the same plants. For the most part, in America we use that second definition. A spice comes from the hardier elements of a plant, not the leaves and stems.
Spices have been the catalyst for world discovery, wars, and immense trade. Indeed, they were invaluable during the earlier centuries of our species’ existence. And why were they so imbued with value? From a chemical standpoint, they often were seen as powerful preservatives, and have the ability to hide spoilage in meats (both with strong flavor and chemical compounds inhospitable to bacteria). Of course, many a medicine can draw its roots back to a specific spice as well. Much early medicine was based on the natural world, and as spices are full of volatile chemical compounds they can have startling effects on the body when used in specific quantities.
How do spices convey their flavors to our foods? Those chemical compounds that were viewed to be medicinal are the key to flavor. We call them volatile compounds, and are sometimes understood as essential oils. They are found in specialized cells, glands, or vessels and can occur throughout any and all parts of the plant, though they are most often concentrated in either leaves or seeds. It is unclear why a plant might develop these compounds, they have no specific value to a plant’s growth. But, as mentioned earlier, they are toxic to bacteria, insects, and animals (to a small degree), so they might have developed as defense mechanisms to keep a plant alive and able to propagate.
These oils are considered volatile because they readily disperse in the air, that is to say, they explode, they are quite volatile. As such, once the cells are broken open and the oils have been exposed, the flavor compounds will diffuse over time. Which, of course, means that spices freshly ground will always give you the best, most potent, flavor.
Let’s look at the common seasonings of the season now, shall we?
Cinnamon is neither leaf, stem, nor seed. What is it then? It is bark! Yes, cinnamon is harvested by carefully separating the outermost layers of bark from trees, and when it is cut away in thin sheets it readily curls in on itself (which is why we see cinnamon sold as sticks). There are two kinds of cinnamon found in markets. True cinnamon is tan, rather lightly colored, and has a subtle flavor. What we consume most of the time is actually cassia. Cassia trees are native to Asia and are much more strongly scented.
Cloves, again, are neither leaf, stem, nor seed. They are actually tiny dried floral buds of a tropical tree native to the East Indies. Its oil has been known for centuries to have local anesthetic properties, and is still sometimes used to alleviate toothaches.
Mace is the outer layer of a spice we know quite well this time of year, the nutmeg. It is separated by hand and then dried. Often used in Indonesian recipes, it has a flavor reminiscent of nutmeg, though it also shares some chemistry with tea tree oil.
Now to nutmeg, that hearty little seed. Yes, nutmeg is not a nut, but rather a seed. It is the shelled seed of an evergreen tree native to the East Indies. A component of its oil is a hallucinogen and must be viewed with much consideration and care.
llspice is named because it seems to hold the flavors of all our favorites in its grasp. That, of course, is entirely incorrect. It is the dried berry of a tropical plant, native to the West Indies. Spanish explorers loved it and traded it around, the spice can be found showing up in British recipes in the 1600s.
Though we are loathe to admit it, black pepper also belongs in this category. And it has a reputation for being the most consumed spice worldwide. The corns we know to be ground are tiny fruits that, upon being picked, are allowed to ferment and dry in the sun before being packaged and shipped.
And what is the best way to make use of these spices? Well considering that the flavors are contained in oils (remember, volatile oils) we must acknowledge the inherent challenge with their dispersion in water. We are all well aware that oil and water do not mix, so when we whisk ground spices into watery substances their flavor compounds will not be activated, or evenly distributed. However, when we fry the spices in fat (another oil) the flavor compounds are activated and released. That is precisely why many recipes call for spices to be fried before being added to a stew or braise. It is curious, however, that we rarely use that technique in baked goods. Imagine how much more flavor you would get from your cinnamon if you fried it in butter before folding into a pumpkin bread?