Big-Pot Blanching: Asparagus
Blanching vegetables involves cooking them quickly in generously salted water to draw out their vibrant flavors and colors. The dull color you often see in raw green vegetables occurs because of the layer of gas that exists between the pigment and the skin. Blanching them releases that gas, allowing the pigment to reach the surface of the vegetable. If you overcook a vegetable, its acids and enzymes escape, and the pigment seeps into the water. This process dulls the color.
When blanching, your vegetables can go from bright to dull and overcooked very quickly, so the challenge is to cook the vegetables without losing color. These important steps will help you get this right: use a large quantity of water, and use a
generous amount of salt (about a cup per gallon of water). If you are planning on serving the vegetables later, have an ice bath ready top the vegetables from cooking and preserve its vibrant color.
Texture is a matter of personal preference. Chef Keller likes his blanched green vegetables with slight resistance to the tooth. To prepare vegetables for blanching, make sure you have a good L’Econome (French peeler), a Swiss peeler, or an abrasive green scrub pad, and read the blanching overview before you begin.
- 1 pound asparagus
- Kosher salt
- Cutting board
- Chef’s knife
- Paring knife
- Loaf pan
- Parchment for trim
- Abrasive green scrub pad
- Butcher’s twine
- Kitchen shears
- 12-quart stockpot
- Mesh skimmer
- Serving plate
- Ice bath
To trim, use a paring knife to peel off the spiky tips along the stalk of the asparagus, along with the woodiest leaves just below the tip. You also want to snap off the most fibrous bottom section of the spear. To do this, use one hand to hold the spear gently in the center of the stem and the other hand at the base and snap. It should break off cleanly where the tough, fibrous section meets the tender part of the spear. It is important to elevate the asparagus off the table while peeling or scrubbing by using a loaf pan. This preserves the integrity of the asparagus by avoiding unnecessary bending or breaking.
Determine whether to use a peeler or an abrasive green scrub pad on the asparagus. A green scrub pad is best used on asparagus with a narrow diameter, as this will prevent excess removal of the asparagus.
Fill the stockpot with water to within a few inches of the top. You want to use a generous amount so that the water retains its heat when you add the vegetables. Bundle and tie 6 to 7 asparagus (depending on the size); asparagus tips are fragile, and bundling helps protect them from damage during blanching. Add salt to the boiling water and take a minute to let it return to a boil. Make sure you add enough salt to the water—Chef Keller says your water should taste as salty as seawater. Place asparagus bundles in boiling water. Add only the amount of asparagus bundles to maintain the rapid boil. The blanching process may require several batches. After 2½ minutes, use the tip of a paring knife to check for doneness. If necessary, continue cooking until tender.
If you’ll be working with the asparagus further—grilling it, for example, or preparing a sauce for it—shock in the ice bath to stop the cooking process and cool it enough for you to work with. If you’re serving the asparagus immediately, simply cut away the twine and arrange the asparagus spears on a platter. Garnish as desired.