Blanch | Blanch definition | How to blanch

Blanch Definition

Definition of blanch – Blanching is a process wherein the food, usually a vegetable or fruit, is scalded in boiling water.
It is removed after a brief time, and finally plunged into iced water or placed under cold running water to shock or refresh into stopping the cooking process.

Why Blanch

  1. Blanch cooking is used to preserve colour and texture in foods, to prepare ingredients ahead of time.
  2. Blanching is commonly used to remove skins from tomatoes and almonds.
  3. It also wilts or softens vegetables and makes them easier to pack for freezing.
  4. It stops enzyme actions which can cause loss of flavour, colour and texture.
  5. This method is also good to soften foods, partly or fully cook, or to remove a strong taste, for example in cabbage or onions.
  6. Blanching certain vegetables like broccoli, kale, spinach or silverbeet will make their colours more vivid.
  7. Blanching cleanses the surface of dirt and organisms, brightens the colour and helps retard loss of vitamins.

How To Blanch

Blanching (scalding vegetables in boiling water or steam for a short time) is a must for almost all vegetables to be frozen.

Blanching time is crucial and varies with the vegetable and size.
Underblanching stimulates the activity of enzymes and is worse than no blanching.
Overblanching causes loss of flavour, colour, vitamins and minerals. See recommended blanching times.

Water Blanching

For home freezing, the most satisfactory way to heat all vegetables is in boiling water.
Use a blancher which has a blanching basket and cover, or fit a wire basket into a large pot with a lid.

  • Use 4.5 litres(1 gal) water per 0.5 kg (1 lb) of prepared vegetables.
  • Put the vegetable in a blanching basket and lower into vigorously boiling water.
    Place a lid on the blancher.
  • The water should return to boiling within 1 minute, or you are using too much vegetable for the amount of boiling water.
  • Start counting blanching time as soon as the water returns to a boil.
  • Keep heat high for the time given in the directions for the vegetable you are freezing.
  • Steam Blanching

    Heating in steam is recommended for a few vegetables.
    For broccoli, pumpkin, sweet potatoes and winter squash, both steaming and boiling are satisfactory methods.
    Steam blanching takes about 1½ times longer than water blanching.

    To steam, use a pot with a tight lid and a basket that holds the food at least three inches above the bottom of the pot.

    1. Put an inch or two of water in the pot and bring the water to a boil.
    2. It stops enzyme actions which can cause loss of flavour, colour and texture.
    3. Put the vegetables in the basket in a single layer so that steam reaches all parts quickly.
    4. It stops enzyme actions which can cause loss of flavour, colour and texture.
    5. Cover the pot and keep heat high. It stops enzyme actions which can cause loss of flavour, colour and texture.
    6. Start counting steaming time as soon as the lid is on. See steam blanching times recommended for the vegetables listed below.

    Microwave Blanching

    Microwave blanching may not be effective, since research shows that some enzymes may not be inactivated.
    This could result in off-flavours and loss of texture and colour.

    Those choosing to run the risk of low quality vegetables by microwave blanching should be sure to work in small quantities, using the directions for their specific microwave oven.

    Microwave blanching will not save time or energy.

    Cooling

    As soon as blanching is complete, vegetables should be cooled quickly and thoroughly to stop the cooking process.

    1. To cool, plunge the basket of vegetables immediately into a large quantity of cold water.
    2. Change water frequently or use cold running water or ice water.
      If ice is used, about 4.5 litres(1 gal) ice per 0.5 kg (1 lb) is needed.
    3. Cooling vegetables should take the same amount of time as blanching.
    4. Drain vegetables thoroughly after cooling.
      Extra moisture can cause a loss of quality when vegetables are frozen.

    Blanching Times

    Blanching times are for water blanching unless otherwise indicated.

    Vegetable Type
    Blanching Time (minutes)
    Artichoke-Globe(Hearts)
    7
    Artichoke-Jerusalem
    7
    Asparagus
    Small Stalk
    Medium Stalk
    Large Stalk
     
    2
    3
    4
    Beans-Snap, Green, or Wax
    3
    Beans-Lima, Butter, or Pinto
    Small
    Medium
    Large
     
    2
    3
    4
    Beets
    Cook
    Broccoli
    (flowerets 3.5cm (1½”) across
    Steamed
     
    3
    5
    Brussel Sprouts
    Small Heads
    Medium Heads
    Large Heads
     
    3
    4
    5
    Cabbage or Chinese Cabbage
    (shredded)
    Carrots
    Small
    Diced, Sliced or Lengthwise Strips
     
    5
    2
    Cauliflower
    (flowerets, 2.5cm (1″) across
     
    3
    Celery
    3
    Corn-on-the-cob
    Small Ears
    Medium Ears
    Large Ears
    Whole Kernel or Cream Style
    (ears blanched before cutting corn from cob)
     
    7
    9
    11

    4

    Eggplant
    4
    Greens
    Collards
    All Other
     
    3
    2
    Kohlrabi
    Whole
    Cubes
     
    3
    1
    Mushrooms
    Whole (steamed)
    Buttons or Quarters (steamed)
    Slices steamed)
     
    5

    3
    Okra
    Small Pods
    Large Pods
     
    3
    4
    Onions
    (blanch until center is heated)
    Rings
     
    3-7
    10-15 seconds
    Peas-Edible Pod
    1½ – 3
    Peas-Field (blackeye)
    2
    Peas-Green
    Peppers-Sweet
    Halves
    Strips or Rings
     
    3
    2
    Potatoes (New)
    3-5
    Pumpkin
    Cook
    Rutabagas
    3
    Soybeans-Green
    5
    Squash-Chayote
    2
    Squash-Summer
    3
    Squash-Winter
    Cook
    Sweet Potatoes
    Cook
    Turnips or Parsnips
    Cubes
    2

    How To Blanch Vegetables

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