Session 42 — Blanching, Shocking, and Color Science
← Block 11–12: Vegetables & PlantForward Cooking Overview
Skill: Blanching (brief boiling) plus shocking (ice bath) is the professional technique for preserving color, texture, and nutritional value in vegetables. It's also the mise en place move for any vegetable that needs to be partially cooked ahead of service.
📖 Read: Serious Eats — How and Why to Blanch Vegetables
The color science — why it matters:
| Pigment | Vegetable examples | Acid effect | Alkali effect |
|---|---|---|---|
| Chlorophyll (green) | Broccoli, asparagus, spinach, peas | Turns drab olive — add lemon after cooking | Stays bright green — small pinch of baking soda in boiling water |
| Anthocyanin (red/purple) | Red cabbage, purple carrots, beets | Stays vivid — add acid (vinegar) to braising liquid | Turns blue-green; avoid alkali |
| Carotenoid (orange/yellow) | Carrots, squash, sweet potato | Stable in acid | Stable — heat-resistant, fat-soluble (cook in fat for best color) |
| Betanin (deep red) | Beets | Stable but bleeds | Stable |
The blanching method: 1. Large pot, aggressively salted water (like pasta water), rolling boil 2. Add vegetable in small batches — too many drops the temperature 3. Cook until just tender but with a little resistance (al dente) 4. Shock immediately in salted ice water (the salt prevents leaching) 5. Drain and dry — wet vegetables steam instead of sauté
Full Meal: Blanched and shocked asparagus + haricots verts + broccolini — dressed with brown butter and toasted almonds, served at room temperature
🎥 Compare Notes: For the Best Roasted Vegetables, Start with Steam — Techniquely with Lan Lam — A related approach to tonight's blanch-and-shock: steam first, then roast for color
| Component | Recipe |
|---|---|
| Vegetables | Asparagus, haricots verts, broccolini — all blanched and shocked |
| Dressing | Brown butter + toasted almonds + lemon zest + fleur de sel |
| Protein (optional) | Soft-boiled eggs on top to make it a dinner |
The test: Hold a blanched green bean next to an unblanched one. The color difference is stark. Blanching stops enzymatic activity (which turns vegetables drab) while the ice bath fixes the color at its brightest.