Blanching is a must for most vegetables to be frozen. It slows or stops the enzyme action which can cause loss of flavor, color and texture.
The blanching time is very important and varies with the vegetable and size.
- Underblanching stimulates the activity of enzymes and is worse than no blanching.
- Overblanching causes loss of flavor, color, vitamins and minerals.
- Wash, drain, sort, trim and cut vegetables.
- Use 1 gallon water per pound of prepared vegetables or 2 gallons water per pound leafy greens.
- Put vegetables into blancher (wire basket, coarse mesh bag or perforated metal strainer) and lower into boiling water.
- Or steam blanch: boil 1-2 inches of water in a pot, bring to boil and then put a single layer of vegetables in basket.
- Cover. Start counting blanching time as soon as water returns to a boil.
- Or if steam blanching, start counting immediately.
- Keep heat high for the time given in the directions.
- 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.
- Drain vegetables thoroughly.
- 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 vegetable on a shallow pan and put the pan into the freezer. As soon as the vegetable is frozen, put them into a freezer bag or container. Press out air and seal tightly.
- Frozen vegetables will maintain high quality for 8 to 12 months at zero degrees F or lower.
Vegetable blanching times (water blanching)
|Vegetable||Blanching In boiling water (minutes)||Blanching in steam (minutes)|
|Beans - snap, green or wax||3||5|
|Beans - lima, butter or pinto||Small||2||3|
|Beans - lima, butter or pinto||Medium||3||5|
|Beans - lima, butter or pinto||Large||4||6|
|Broccoli - flowerets||1 1/2 inches across||3||5|
|Brussels sprouts||Small heads||3||5|
|Brussels sprouts||Medium heads||4||6|
|Brussels sprouts||Large heads||5||7|
|Cabbage or Chinese cabbage||Shredded||1 1/2||2 1/2|
|Carrots||Diced, sliced or strips||2||3|
|Cauliflower - flowerets||1 inch||3||5|
|Corn - corn-on-the-cob||Small ears (cooling time is twice the time of blanching)||7||10|
|Corn - corn-on-the-cob||Medium ears (cooling time is twice the time of blanching)||9||13|
|Corn - corn-on-the-cob||Large ears (cooling time is twice the time of blanching)||11||16|
|Corn - whole kernel or cream style||Ears blanched before cutting corn from cob. (cooling time is twice the time of blanching)||4||6|
|Greens - collards||3||5|
|Greens - all other||2||3|
|Mushrooms||Whole (pretreat soak 5 min. in anti-darkening solution: 1 tsp. of lemon juice or 1 ½ tsp. of citric acid to a pint of water.)||-||9|
|Mushrooms||Buttons or quarters (pretreat soak 5 min. in anti-darkening solution: 1 tsp. of lemon juice or 1 ½ tsp. of citric acid to a pint of water.)||-||9|
|Mushrooms||Slices (pretreat soak 5 min. in anti-darkening solution: 1 tsp. of lemon juice or 1 ½ tsp. of citric acid to a pint of water.)||-||5|
|Onions||(blanch until center heated)||3-7||-|
|Peas - edible pod||2-3||4-5|
|Peas - green||1 1/2 - 2 1/2||3-5|
|Peppers - sweet||Halves||3||5|
|Peppers - sweet||Strips or rings||2||3|
|Potatoes - Irish (new)||3-5||5-8|
|Soybeans - green||5||-|
|Squash - summer||3||5|
|Turnips||1/2 inch cubes||3||5|
Fully cook Beets, pumpkin, sweet potatoes, and winter squash prior to freezing. Add tomatoes to boiling water for 30-60 seconds, cool and remove skin.
- University of Minnesota Extension; So Easy to Preserve, 2014, 6th Edition, University of Georgia; Ohio State University, 2020.
- National Center for Home Food Preservation.
Reviewed in 2020