Purple basil, scientifically known by cultivars such as Ocimum basilicum ‘Purpurascens’ or ‘Dark Opal,’ is a visually striking member of the mint family. This distinct variety of the common culinary herb stands out due to its rich, dark coloration. Its popularity stems from its ornamental appeal combined with its unique flavor profile, making it a frequent subject of curiosity for cooks and gardeners. This herb is grown as an annual and is valued for its ability to transform a dish with both color and aroma.
Defining Characteristics and Flavor Profile
Purple basil varieties typically display deep burgundy or violet-colored leaves, often accompanied by dark red or purple stems that contrast with the pink-to-lilac flowers. Cultivars like ‘Purple Ruffles’ feature a deeply textured, crinkled leaf surface, while others have a smoother, glossy appearance. The plant usually reaches a mature height of 18 to 24 inches.
This basil possesses a strong, complex fragrance distinct from its green counterparts. Its flavor profile is less sweet and more intense, featuring prominent notes of licorice or anise. A warm, spicy undertone reminiscent of clove or cinnamon adds depth to its herbal essence. The concentration of these oils gives the purple varieties a robust and slightly peppery taste, which can be overpowering if used in large quantities.
Key Differences from Sweet Basil
The most obvious contrast between purple basil and traditional sweet basil, such as the Genovese type, is the presence of color-producing compounds called anthocyanins. These flavonoids are responsible for the deep violet pigmentation and are the same pigments found in blueberries and purple cabbage. The accumulation of these compounds gives purple basil a distinct nutritional advantage.
Anthocyanins function as powerful antioxidants, providing a health benefit that green basil does not offer to the same degree. However, this unique chemistry affects the herb’s stability during preparation. When purple basil is exposed to heat, the anthocyanin pigments break down, causing the leaves to turn a muddy green or black color. This loss of color is accompanied by a quicker degradation of its delicate flavor compared to the more heat-tolerant sweet basil. Furthermore, some purple cultivars exhibit a slightly different growth habit, sometimes growing more slowly or with a bushier form than their green relatives.
Culinary Applications and Preservation
Purple basil’s dark hue makes it an excellent choice for ornamental use, functioning primarily as a garnish for salads, cocktails, or Caprese arrangements. Its robust flavor is best showcased when used raw, allowing the spicy and anise notes to remain intact. A popular application is creating vibrant herb-infused liquids, such as red wine vinegar or olive oils, where the color bleeds into the medium.
While it can be used to make pesto, the resulting paste often quickly loses its bright purple color and develops a muddy, greenish-brown tone upon blending. To maximize color retention, some cooks briefly blanch the leaves or blend them with a smaller amount of green basil. For long-term storage, freezing is the preferred method over drying, as the delicate oils and color are easily lost when the leaves are dehydrated. Freezing the leaves, either whole or blended with oil in ice cube trays, preserves the flavor and color more effectively for later use in cooked dishes and sauces.