Blanching times start when the water returns to a full boil after adding the vegetables (not when you first put them in). Use at least one gallon of boiling water per pound of prepared vegetables. After blanching, immediately transfer to an ice-water bath and cool for the same amount of time as the blanching duration. Drain thoroughly before packaging.
Steam blanching times are approximately 50% longer than water blanching times. Steam blanching is preferred for broccoli, leafy greens, and delicate vegetables that absorb too much water during boiling. See the techniques page for detailed blanching instructions.
| Vegetable | Preparation | Water Blanch | Steam Blanch |
|---|---|---|---|
| Asparagus (thin) | Trim ends | 2 minutes | 3 minutes |
| Asparagus (thick) | Trim ends | 4 minutes | 6 minutes |
| Green beans | Trim, cut or leave whole | 3 minutes | 4.5 minutes |
| Broccoli | Cut into florets | 3 minutes | 5 minutes |
| Brussels sprouts (small) | Trim, halve if large | 3 minutes | 5 minutes |
| Brussels sprouts (large) | Trim, halve | 5 minutes | 7.5 minutes |
| Carrots (sliced) | Peel, slice ¼ inch | 2 minutes | 3 minutes |
| Carrots (diced) | Peel, dice | 2 minutes | 3 minutes |
| Cauliflower | Cut into florets | 3 minutes | 5 minutes |
| Corn on the cob (small) | Husk, remove silk | 7 minutes | 10 minutes |
| Corn on the cob (large) | Husk, remove silk | 11 minutes | 16 minutes |
| Corn kernels | Cut from cob after blanching on cob 4 min | 4 minutes | 6 minutes |
| Eggplant | Peel, slice ⅓ inch | 4 minutes | 6 minutes |
| Greens (spinach, kale, chard) | Wash, remove stems | 2 minutes | 3 minutes |
| Collard greens | Wash, remove stems | 3 minutes | 4.5 minutes |
| Okra (small pods) | Trim stems | 3 minutes | 4.5 minutes |
| Okra (large pods) | Trim stems | 4 minutes | 6 minutes |
| Peas (shelled) | Shell | 1.5 minutes | 2.5 minutes |
| Peas (snow/sugar snap) | Trim ends, string | 2 minutes | 3 minutes |
| Peppers (strips or rings) | Seed, cut | 2 minutes | 3 minutes |
| Potatoes (diced, cubed) | Peel, cut | 3 to 5 minutes | 5 to 7 minutes |
| Summer squash / zucchini | Slice ½ inch | 3 minutes | 4.5 minutes |
| Sweet potatoes | Peel, cut into pieces | Cook until tender | N/A |
| Turnips | Peel, dice | 2 minutes | 3 minutes |
A few vegetables can be frozen without blanching, either because they have low enzyme activity or because their intended use does not require it:
Onions and garlic — chop and freeze directly in bags. Their strong sulfur compounds naturally suppress enzyme activity.
Peppers — can be frozen raw without blanching if used within a few months. For longer storage, blanching is recommended.
Tomatoes — can be frozen whole, halved, or chopped without blanching. The texture will be soft when thawed (suitable for cooking, not fresh eating).
Herbs — freeze in oil or water in ice cube trays without blanching. See the herbs freezing guide for details.
Mushrooms — should be sautéed rather than blanched before freezing. Raw mushrooms have too much moisture and become rubbery. See the mushrooms page.