Wasabi, primarily known for its pungent root in Japanese cuisine, offers more than just its subterranean stem. The leaves of the wasabi plant (Eutrema japonicum or Wasabia japonica) have unique characteristics and culinary potential. This article explores their features, flavor, culinary uses, growing considerations, and storage.
Understanding Wasabi Leaves
Wasabi leaves are part of the Eutrema japonicum plant, belonging to the Brassicaceae family, which includes horseradish and mustard. They are large, heart- or kidney-shaped, growing up to 6 inches (15 cm) in diameter. These glossy, deep green leaves feature prominent palmate veins radiating from the petiole, or leaf stalk.
They often have undulated and serrated margins. Young leaves may have a purple tint, turning green with maturity. Unlike the rhizome, the leaves emerge from the plant’s crown.
Edibility and Flavor Profile
Wasabi leaves are edible and offer a milder, distinct flavor compared to the intensely pungent rhizome. They have a fresh, peppery, mildly sharp bite, with grassy, green, and subtly sweet notes, reminiscent of spinach and mustard greens. While the root’s heat quickly dissipates, the leaves provide a more subdued and fleeting pungency. This milder profile makes them versatile for culinary uses without overpowering other ingredients, unlike the intense heat of the grated rhizome.
Culinary Applications
Wasabi leaves are extensively versatile in cooking, allowing for both raw and cooked preparations. Fresh leaves can be added to salads, providing a peppery kick that enhances flavor. They are also excellent as garnishes, adding visual appeal and a subtle bite to dishes. For a unique twist, larger leaves can serve as healthy alternatives for wraps or even wasabi-wrapped sushi.
They can also be incorporated into cooked dishes. They can be lightly sautéed, stir-fried, or blanched; some sources suggest their flavor becomes similar to sautéed spinach. They also hold up well to tempura frying, retaining their mild pungency.
The crisp, milder stems can be finely chopped for noodle dishes or as a garnish. Both leaves and stems are traditionally pickled, as in wasabi-zuke, a Japanese pickle made with sake lees. They can also be blended into pestos or sauces for a unique flavor.
Growing Wasabi Leaves
Growing wasabi is challenging due to its specific environmental requirements. Wasabi thrives in cool temperatures, ideally between 45°F to 75°F (7°C to 24°C), and requires consistent moisture without being waterlogged. It is a shade-loving plant, needing at least 75% shade and no direct sunlight, mimicking its natural habitat along cool mountain streams.
The plant prefers loose, organic-rich soil with a slightly acidic to neutral pH (6.0 to 7.0). While often grown in specialized semi-aquatic systems, it can also be cultivated in containers with a well-draining medium like vermiculite, sand, and gravel. Maintaining high humidity is also important for healthy growth. These precise needs mean growing wasabi requires careful attention to environmental conditions.
Availability and Storage
Fresh wasabi leaves are less common than the rhizome but can be found at specialty markets, some online retailers, or rare garden centers. When purchasing, look for vibrant green leaves without wilting or discoloration.
To maintain freshness, store wasabi leaves like other delicate leafy greens. They can be kept fresh for about one week in the refrigerator. Wrap them in a damp paper towel and place in an open bowl or plastic vegetable bag in the refrigerator to preserve quality. If you have a surplus, wasabi leaves can be blanched and frozen for longer storage, similar to other greens.