Blanch Before You Freeze

Reviewed by Sarah Klemm, RD, CD
blanching spinach

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Freezing is a great way to preserve foods. But when it comes to freezing fresh produce, there is more involved than just putting foods directly into the freezer. One solution to this problem is to blanch vegetables before you freeze them. Blanching reduces enzyme action in food, which helps vegetables retain their color and flavor.

Note: Blanching is great for many vegetables and some firm fruits, such as apples and pears. Other foods, such as meat, don’t need to be blanched before freezing.

What is Blanching?

Blanching is a process where food is exposed to boiling water or steam for a brief period and then quickly placed in ice water to prevent it from cooking all the way through.

The amount of time needed to blanch different vegetables varies. And, it is important to follow the recommended times for specific vegetable because over-blanching leads to a loss of flavor, color and nutrients, whereas under-blanching can increase enzyme activity. Check the blanching chart below for the appropriate blanching times.

Why Blanch?

Here are a few reasons to blanch vegetables:

  • Blanching helps to preserve the flavor, color and texture of fresh produce that’s being frozen.
  • Blanching helps slow the loss of vitamins.
  • Blanching helps cleanse the surface of dirt and some bacteria.

How To Blanch?

There are two major steps involved in blanching foods. First, the vegetables must be submerged in boiling water. Second, they must be cooled quickly.

For every pound of vegetables, use at least one gallon of water to blanch them in. Leafy green vegetables require twice as much water – so two gallons of water for every one pound of leafy green. Before blanching, wash vegetables and remove the peels or skins if desired. If you plan on freezing your vegetables sliced, chopped or cut, do this before blanching.

When the water is boiling, just add the vegetables to the pot and cover tightly. The water should return to boiling within a minute of adding the vegetables. As soon as water returns to a boil, the blanching countdown begins. To help remove the vegetables quickly and easily when they’re ready - place the vegetables in a wire basket or secure them in cheesecloth before boiling them.

Vegetables should be cooled quickly and thoroughly to stop the cooking process immediately after blanching. To do this, plunge the vegetables into a large bowl of cold water, 60 degrees Fahrenheit or below. Change the water frequently or use one pound of ice for each pound of vegetables to help keep the water cold. It should take about the same amount of time to cool vegetables as it did to blanch them. Drain vegetables in a colander after they’ve cooled and lay flat on a clean towel or paper towels to let them fully dry. Extra moisture can reduce quality when vegetables are frozen.

Pack your blanched vegetables in food safe, plastic freezer bags or rigid containers before storing in the freezer. Allow some extra space in the container before sealing, as some items may expand when frozen.

See blanching times for various vegetables from The National Center for Home Food Preservation.

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