The Science of Spice

10 Spice Science

Spices have been valued

throughout history, in religious

ceremonies and medicine as

much as in cooking. Science

has shown us that these

once-mystical plant parts are

in fact the vessels of chemicals

known as flavour (or aroma)

compounds, generated to help

plants survive and reproduce,

perfroming roles such as

repelling animals or protecting

against bacteria. By happy

coincidence, many of these

compounds have aromas that

are pleasant to humans.

Cinnamon

New shoots of

coppiced trees are

stripped for their

inner bark to

produce cinnamon.

Turmeric

The rhizomes of

the turmeric plant

look similar to

ginger, of which it

is a close relative.

Dried bark

is rolled by

hand to form

“quills”

Inner bark

is left to dry

in the sun

Rhizomes are the

plant’s food store and

comprise up to 70 per

cent carbohydrate

New shoots

are produced

from nodes

Communication

The spicy, woody aroma of

cinnamon comes from a chemical

compound called caryophyllene.

When a plant is being eaten, its role

is to act as an airborne signal that

“primes” downwind plants to

produce defensive chemicals.

Animal deterrence

Turmeric’s flavour profile includes

a compound called cineole, which

has a strong, penetrating, slightly

medicinal flavour and has evolved

to act as a bitter-tasting

deterrence to animals who try

eating the rhizomes.

STEMS

The stem of a plant distributes water and sugars

to where they are needed. Few spices derive from

stems: lemongrass is the stalk of a tropical grass

and little-known mastic is the dried resin collected

from lentisk trees; more famously, cinnamon and

cassia are dried pieces of inner and outer bark,

respectively, of Cinnamomum trees.

Chemical stores

ROOTS AND

UNDERGROUND STORES

Roots are a plant’s lifeline to water and nutrients, and

rhizomes, corms, and bulbs are storage chambers with

the ability to produce new shoots and roots. Liquorice

comes from dried roots and asafoetida is derived from

dried root sap. Turmeric, ginger, galangal, and garlic

are all examples of underground stores.

Spices are plant parts that are more densely loaded with flavour than most

other ingredients used in cooking. Whereas herbs always come from leafy

parts, spices tend to derive from seeds, fruits, roots, stems, flowers, or bark,

and are usually dried. That said, some strongly flavoured leaves, such as bay

and curry leaf, can be considered spices because they are used more as a

potent background flavouring than as a fresh addition.

WHAT IS A

SPICE?

“

Spice flavours

are chemicals

produced by

plants, often

for defence.

”

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