Do not use zucchini that is pale or soft. Also avoid zucchini that has bruises, deep scratches, or rotted spots. If possible, use zucchini that has been freshly harvested from the garden. If buying zucchini from the store, make sure that it is in the refrigerated section and in ripe condition. If you cannot freeze the zucchini right away, refrigerate it until you can. Make sure that it is still in firm, ripe condition before freezing it, though.

If necessary, you could also gently scrub the skin with a soft vegetable brush.

Use a sharp knife to remove 1/4 inch (6. 35 mm) from each end of the zucchini. If slicing the zucchini, use a knife to cut the remainder of the vegetable into 1/2-inch (1. 27-cm) thick slices. If cutting the zucchini into small cubes, begin by first cutting the zucchini in half lengthwise. Remove the seeds with a metal spoon and cut the vegetable into cubes. If shredding the zucchini, use a box grater to grate the remainder of the zucchini into fine shreds. You could also use a food processor to coarsely chop the zucchini into shreds. [4] X Research source

Prepare a steaming basket for grated zucchini. Grated zucchini needs to be blanched, too, but it should be blanched using steam instead of boiling water. Fill the pot with roughly 2 inches (5 cm) of water and place a steaming basket or other mesh basket over the pot. Bring the water to a boil over medium-high to high heat. Blanching is a beneficial step because it removes the enzymes and bacteria that cause the zucchini to lose flavor, color, and nutrition over time. If you do not blanch the zucchini, it will discolor relatively quickly, even when stored in the freezer. Do not add any salt to the water. When blanching vegetables to eat immediately, salt makes them more flavorful. When blanching vegetables to store them, however, adding salt can actually cause the vegetable to lose moisture and break down faster.

The cold water should be prepared before you blanch the zucchini.

Cook sliced zucchini, uncovered, in the boiling water for 3 to 4 minutes. It should still be firm when you take it out. Place shredded zucchini in your steaming basket and cover the pot. Steam the zucchini for roughly 2 minutes, or until it becomes translucent. You can safely reuse blanching water for up to five batches. Make sure to refill the pot with additional hot water as the water level drops, though.

Suddenly dunking the zucchini in ice water immediately stops the cooking process. Keep the zucchini in the ice water for approximately the same amount of time you kept it in boiling water or steam.

You could also transfer the zucchini to a colander and allow it to drain on its own. Either way, make sure that the zucchini is dry before attempting to freeze it.

Pre-freezing the zucchini prevents the zucchini from sticking together in the freezer, making it possible to measure out precise amounts of frozen zucchini rather than thawing the entire batch. Make sure that the pieces do not overlap or touch each other. Any pieces that overlap are likely to stick together. Note that this pre-freezing stage is not necessary if you are using shredded zucchini.

Larger pieces will take longer to freeze than smaller ones.

Leave roughly 1/2-inch (1. 27-cm) of empty headspace at the top if each container to allow the zucchini room to expand as it freezes. Avoid using glass containers, which are more likely to shatter in the freezer. If using a bag, make sure that you squeeze as much air out of the bag as possible. The closer it is to being airtight, the longer it will last without getting freezer burn or losing flavor. Label the bag or container with the current date so that you can keep track of how long you’ve had the zucchini in storage. Divide shredded zucchini into pre-measured amounts based on how much you anticipate needing at a time. For instance, you could try separating the zucchini into 1 cup (250 ml) portions. Place each portion in its own separate bag or container and label with the current date as well as the amount.

After thawing out the zucchini, use it within 3 days and do not attempt to re-freeze it.