Bulletin #4384, Freezing Vegetables

Canning & Freezing Quick-Guides

Bulletin #4384, Freezing Vegetables (PDF)

UNH Extension logo

Prepared by Ann Hamilton, Food Safety Field Specialist, University of New Hampshire; reproduced with permission.

For information about UMaine Extension programs and resources, visit extension.umaine.edu.
Find more of our publications and books at extensionpubs.umext.maine.edu.

Why Blanch Vegetables?

tomatoes on the vineBlanching is the process of scalding vegetables in boiling water or steam for a short amount of time. Blanching is a must for most vegetables that are frozen. The blanching process is important to slow or stop enzyme action that causes loss of flavor, color, and texture. Blanching time is important and varies with the vegetable and size of the pieces. Under blanching stimulates the activity of enzymes and is actually worse than no blanching. Over blanching causes the loss of flavor, color, vitamins, and minerals.

Blanching Directions

  1. blanching potWash, drain, sort, trim and cut vegetables.
  2. Use 1-gallon water per pound of prepared vegetables or 2 gallons water per pound of leafy greens.
  3. Put vegetables into blancher (wire basket, coarse mesh bag or perforated metal strainer) and lower into boiling water. Or steam blanch: Add 1-2 inches of water to a pot and bring to boil then put a single layer of vegetables in the basket.
  4. Cover. Start counting blanching time as soon as the water returns to a boil. If steam blanching, start counting immediately.
  5. Keep heat high for the time given in the directions.
  6. Cool immediately in ice water or cold water (60 degrees F or below) for the same time used in blanching (except for corn on the cob for which cooling time is twice the time of blanching). Stir vegetables several times during cooling.
  7. Drain vegetables thoroughly.
  8. Pack the vegetables either by dry-pack or tray-pack.
    • Dry-pack: Pack vegetable tightly into containers or freezer bags. Press out air and seal tightly.
    • Tray-pack: Put a single layer of the vegetables in a shallow pan and put the pan into the freezer. As soon as the vegetables are frozen, put them into a freezer bag or container. Press out air and seal tightly.
  9. Freeze.
  10. Frozen vegetables will maintain high quality for 8 to 12 months at zero degrees F or lower.

Important Note

Freeze food at zero degrees Fahrenheit or lower. Do not overload the freezer when freezing vegetables. It will take longer to freeze. Frozen vegetables will maintain high quality for 8 to 12 months at zero degrees F or lower.

Containers for Freezing

Using proper packaging material for freezing food is important to help protect flavor, color, moisture content and nutritive value of the food while in the freezer.

In general, rigid containers, such as glass and plastic, are suitable for all packs, especially for liquid packs. Regular glass breaks easily at freezer temperatures. If using glass jars, choose wide mouth jars that are made for freezing and canning. Plastic freezer-grade bags are good for dry pack with little to no liquid. If using plastic bags, press them to remove as much air as possible before closing.

General characteristics of packaging materials should be:

  • Moisture vapor resistant
  • Durable and leakproof
  • Made of freezer grade material
  • Resistant to oil, grease or water
  • Protect foods from absorption of off-flavor or odors
  • Easy to seal – use freezer tape if needed to reinforce the seal
  • Easy to label and date
  • Containers that hold less than a one-half gallon

Did You Know?

Headspace is the unfilled space above the food in a container and below the top of the lid that allows the food to expand during freezing.


Vegetable: Asparagus

Preparation: Wash. Sort according to thickness. Discard tough part of the stalk. Cut into even lengths to fit the container. Blanch, cool, and drain package, leaving no headspace. Label, date, and freeze.

Blanching Time (minutes): Small- 2 Medium – 3 Large – 4

Vegetable: Beans (Snap, Green or Wax)

green beansPreparation: Wash. Remove ends. Snip or cut into 2-4 inch lengths. Blanch, cool, drain and package, leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time (minutes): 3

Vegetable: Beets

Preparation: Wash and sort according to size. Trim tops, leaving 1/2 inch stem and root. Cook in boiling water until tender, for small beets 25-30 minutes; for medium beets 45-50 minutes. Cool in cold water, peel, remove stem and root and cut into slices or cubes. Package leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time: Cook until tender

Vegetable: Broccoli

Preparation: Remove leaves and woody portions. Wash. If desired, soak 30 minutes in brine (4 tsp. salt to 1-gallon water) to remove insects. Trim flowerets to 1 to 1 1/2 inch across. Blanch, cool, drain and package, leaving no headspace. Label, date, and freeze.

Blanching Time (minutes): 3 or steam 5

Vegetable: Brussel Sprouts

Preparation: Select green, firm and compact heads. Trim, wash and sort according to size. Blanch, cool, drain and package leaving no headspace. Label, date, and freeze.

Blanching Time (minutes): Small – 3 Medium – 4 Large – 5

Vegetable: Carrots

Preparation: Remove tops, wash, and peel. Cut as desired. Leave small carrots whole. Blanch, cool, drain and package leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time (minutes): Whole – 5 Cut – 2

Vegetable: Cauliflower

Preparation: Wash. If desired, soak 30 minutes in brine (4 tsp. salt to 1-gallon water) to remove insects. Trim head into 1-inch pieces across. Blanch in water containing 4 teaspoons salt per gallon of water. Cool, drain and package, leaving no headspace. Label, date, and freeze.

Blanching Time (minutes): 3

Vegetable: Corn

Preparation: Select tender, freshly gathered corn. Husk, trim, remove silk and wash. Blanch, cool quickly and completely, drain and package, leaving no headspace.

  • On the Cob
    Preparation: Husk, trim, remove silk and wash. Blanch, cool quickly and completely, drain and package, leaving no headspace.
    Blanching Time (minutes): Small – 7 Medium – 9 Large – 11
  • Whole Kernel
    Preparation:
    Blanch corn on cob. Cool, drain and cut to about 2/3’s the depth of the kernel. Package, leaving 1/2 inch headspace.
    Blanching Time (minutes): 4
  • Cream Style
    Preparation: Blanch corn on the cob. Cool and drain. Cut kernel tips from the cob and scrape the cobs with the back of a knife to remove juice and heart of the kernel. Package, leaving 1/2 inch headspace.
    Blanching Time (minutes): 4

Vegetable: Greens (including swiss chard, spinach & collards)

Preparation: Select young tender leaves. Wash thoroughly. Remove woody stems. Blanch, chill, drain and package, leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time (minutes): 2; Collards – 3

Vegetable: Herbs

Preparation: Wash, drain, pat dry. Wrap in freezer wrap and place in a freezer bag. Freeze. Use in cooked dishes. Label, date, and freeze.

Blanching Time (minutes): N/A

Vegetable: Peas, Green

Preparation: Use young, tender peas. Shell, blanch, cool and drain. Package leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time (minutes): 1 1/2 to 2 1/2

Vegetable: Peas, Edible pod

Preparation: Select flat, tender pods. Wash. Remove stems, blossom ends, and strings. Leave whole. Blanch, cool, drain and package, leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time (minutes): Small – 2; Large – 3

Vegetable: Peppers (bell or sweet)

Preparation: Wash, stem, and seed. If desired, cut into 1/2 inch strips or rings.

  • Heated: Blanch, cool, drain and package leaving 1/2 inch headspace. Use in cooking.
  • Raw: Spread loosely on a tray. Freeze, then pack, leaving no headspace. Use in uncooked or cooked foods. Label, date, and freeze.

Blanching Time (minutes): Halves – 3; Strips – 2

Vegetable: Pumpkin or Winter Squash

Preparation: Wash. Cut into pieces and remove seeds. Cook until soft. Remove pulp and mash. Cool quickly by placing the pan in cold water. Package leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time: Cook

Vegetable: Summer Squash (including zucchini)

Preparation: Wash and cut into 1/2 inch slices. Blanch, cool, drain and package, leaving 1/2 inch headspace. Label, date, and freeze.

Blanching Time (minutes): 3

Vegetable: Zucchini (grated)

Preparation: Wash and grate young tender zucchini. Steam blanch small amounts. Package, leaving 1/2 inch headspace. Cool by placing containers in cold water. Pack in measuring amounts. Best used for baking. Label, date, and freeze.

Blanching Time (minutes): Steam 1 to 2

Vegetable: Tomatoes

Preparation: Wash and dip in boiling water for 30 seconds to loosen skin. Peel and core. Freeze whole or in pieces. Package, leaving 1-inch headspace. Use for cooking. Label, date, and freeze.

Blanching Time (minutes): N/A

For More Information

For more information on food preservation, go to the National Center for Home Food Preservation Website.

New Hampshire Extension
State Office
Taylor Hall
59 College Rd.
Durham, NH 03824

Education Center and Information Line
answers@unh.edu
1.877.EXT.GROW (1.877.398.4769)
9:00 a.m.–2:00 p.m., Monday-Friday


Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

© 2007, 2009, 2019

Call 800.287.0274 (in Maine), or 207.581.3188, for information on publications and program offerings from University of Maine Cooperative Extension, or visit extension.umaine.edu.

The University of Maine is an EEO/AA employer, and does not discriminate on the grounds of race, color, religion, sex, sexual orientation, transgender status, gender expression, national origin, citizenship status, age, disability, genetic information or veteran’s status in employment, education, and all other programs and activities. The following person has been designated to handle inquiries regarding non-discrimination policies: Director of Equal Opportunity, 101 North Stevens Hall, University of Maine, Orono, ME 04469-5754, 207.581.1226, TTY 711 (Maine Relay System).