Understanding Kohlrabi's Unique Structure
Kohlrabi, whose name is derived from the German words for cabbage (kohl) and turnip (rabi), is a unique and often misunderstood vegetable. It is a cruciferous vegetable, like broccoli and kale, and is essentially a swollen stem that grows above the ground. The bulbous stem is the most commonly consumed part, but the leaves are also edible when prepared correctly. While the interior flesh of both green and purple varieties is a similar pale white or yellow color, the exterior skin color is the only significant visual difference.
The Edibility of Purple Kohlrabi Skin
The short answer is yes, the purple skin of kohlrabi is edible, but with a significant caveat. Edibility doesn't always equate to palatability. The skin, regardless of color, is known for being thick, tough, and fibrous. For most culinary applications, this texture is undesirable and will not soften significantly even after being cooked. Therefore, most chefs and home cooks recommend peeling the kohlrabi bulb thoroughly. The purple variety's skin does not taste different from the green variety's skin, and the flavor of the flesh inside is virtually identical between the two.
Nutritional Benefits in the Purple Pigment
The beautiful purple hue of kohlrabi's skin is due to the presence of anthocyanins, a powerful type of antioxidant. Anthocyanins have been linked to several health benefits, including a lower risk of heart disease and improved brain function. While the skin contains these beneficial compounds, the overall nutritional profile of the kohlrabi bulb itself is already impressive. The internal flesh is packed with vitamin C, fiber, potassium, and B6. If you want to consume the anthocyanins from the skin, consider these options:
- Finely grating the skin from a young, tender kohlrabi.
- Roasting thin skin peels until they become crispy, similar to vegetable chips.
- Making a vegetable stock where the skin can be strained out later.
Size Matters for Texture
The size and age of the kohlrabi bulb are crucial factors when considering whether to leave the skin on. Smaller, younger kohlrabi (around 3 inches in diameter) tends to have more tender skin that might be tolerable in some raw preparations, such as a finely grated slaw. However, as kohlrabi matures and grows larger, the outer layer becomes increasingly tough, fibrous, and even woody. For larger specimens, peeling is a non-negotiable step to avoid an unpleasant, stringy texture in your finished dish.
Comparing Peeled vs. Unpeeled Kohlrabi Skin
| Feature | Peeled Kohlrabi | Unpeeled Kohlrabi | Considerations for Both |
|---|---|---|---|
| Taste | Mild, sweet, and slightly peppery, like a broccoli stem. | The taste is not significantly different from the flesh, but texture can be distracting. | Flavor is generally subtle and versatile. |
| Texture | Crisp and crunchy, resembling an apple or radish. | Tough, rubbery, and fibrous, especially in larger bulbs. | Smaller, younger bulbs have more tender skin than larger, older ones. |
| Nutrients | High in Vitamin C, fiber, and other minerals. | Contains additional anthocyanin antioxidants, particularly in the purple skin. | High in overall nutritional value either way. |
| Preparation | Requires a paring knife or sharp peeler to remove the tough outer layer. | Requires less prep time but careful consideration for texture. | Peeling is the most common practice for a pleasant eating experience. |
Step-by-Step Preparation: When and How to Peel
Regardless of color, proper preparation is key to enjoying kohlrabi. If you've decided that peeling is the right choice for your recipe, here is a simple guide:
- Trim the leaves and stems: Use a sharp knife to cut away the leafy stems and the woody base. The leaves can be cooked like kale or other greens.
- Cut into sections: For easier handling, you can cut the kohlrabi bulb into halves or quarters.
- Use a paring knife: The skin is often too thick and uneven for a standard vegetable peeler. A sharp paring knife is the most effective tool to slice away the tough outer layer.
- Remove the woody core: With larger kohlrabi, you may notice a fibrous core inside that should also be cut out and discarded.
- Enjoy raw or cooked: Once peeled, the kohlrabi flesh can be grated for slaws, sliced into matchsticks for dipping, or cooked by roasting, steaming, or sautéing.
Conclusion: Peel for Palatability, Not Safety
The purple skin of kohlrabi is perfectly safe and contains healthy antioxidants, particularly anthocyanins. However, its tough, fibrous, and often rubbery texture is the primary reason it is almost universally peeled and discarded. While adventurous home cooks might find a use for the skin in a stock or as roasted chips, the best practice for most recipes is to remove the skin completely. The real star of the kohlrabi is the sweet, crisp, and peppery flesh inside, which is best enjoyed once freed from its protective—if unattractive to the palate—exterior. The decision to peel, ultimately, comes down to your personal preference for texture rather than any health or safety concerns.
For more information on kohlrabi, check out this guide on FoodPrint.
