How to blanch and freeze vegetables
A Culinary Arts expert explains this simple – but delicate – process
Many things mark the end of summer in Alberta – earlier sunsets, cooler mornings and evenings, and the changing colors of the tree leaves.
To that list, you could add green thumbs who harvest the garden so as not to waste the fruits — and especially the veggies — of their labors.
Preservation techniques are essential. These can take many forms from pickling to making jellies to fermenting hot sauces and more.
But you can only eat so many pickles and canned foods. Sometimes all you want during the cold, snowy months is a hearty soup or stew that calls for whole vegetables. This is where blanching and freezing come in.
Corresponding Linda Sutherland (Culinary Arts ’18), lab technician for the Culinary Arts program, blanching certain vegetables before freezing them helps preserve their flavor and nutrients.
“It’s the best way to keep the vegetables as fresh as possible,” she says.
Although it sounds easy, blanching can be a delicate process. We asked Sutherland for tips on this time-honored harvesting method so gardeners can enjoy their produce until next planting season.
How to know what can be blanched
“You don’t blanch everything,” says Sutherland.
If it’s green, like green beans, shelled peas, broccoli, and Brussels sprouts, it should be blanched before freezing. However, you can add cauliflower, other beans, and carrots to this list.
(Sutherland suggests enjoying carrots straight from the fridge for as long as possible before blanching and freezing; they keep well on their own and just taste better fresh.)
Sutherland adds that harvesting the blanchable vegetables doesn’t have to wait until the end of summer. This can be done the moment the plants are ready to be picked.
“The basic rule is: when it’s big enough and ripe to eat, you can harvest it. And then until the plant dies.”
Fruit doesn’t need to be blanched before freezing, she adds. Neither do squash or zucchini. If you can’t use them fresh, just dice or puree them before they go in the freezer.
The art of blanching
“The goal of blanching is to keep your vegetables pristine,” says Sutherland, “not to cook them.”
It’s a simple process, but a delicate balance. Sutherland suggests these steps:
- Prepare a pot of water big enough for your yield.
- Prepare a separate ice water bath.
- For most vegetables, salt the pot with water; For white vegetables like cauliflower, use some vinegar or lemon juice instead. (Linda recommends one tablespoon of salt or acid for every four to six liters of water.)
- Bring the pot of water to a boiling boil.
- Add your prepared vegetables (cleaned, peeled, sliced, etc. as needed).
- Cook for no more than a minute.
- Immediately transfer the vegetables to an ice bath to stop cooking.
- Leave the vegetables to cool in the water.
- drain.
“If done successfully, your veggies will have a nice, vibrant color – especially the green veggies – and will retain some firmness.”
This is the most common method, but Sutherland says you can also use a microwave for a very short steam cycle before submerging in the ice bath.
The Art of Freezing
For best results, Sutherland says, layer a single layer of the blanched vegetables on a baking sheet and place flat in the freezer.
“This keeps the veggies from clumping together,” says Sutherland. Once they’re frozen — in 15 to 30 minutes — place them in a freezer-safe bag or container.
Some freezers are better than others. Vegetables have a shorter shelf life in a refrigerator with a freezer compartment where you often open the door – up to six months. In a chest freezer that isn’t accessed as much, frozen produce should last a year.
Don’t be afraid to make mistakes
If you’re nervous about getting it right, Sutherland recommends practicing with vegetables that you have plenty of and maybe a smaller amount of. When things don’t work out, you’ll know: they slowly turn pale even when frozen, then turn slightly brown upon thawing and lose some flavor, texture, and nutrients.
In general, however, they are not inedible if you cook them the way you choose.
“If you screw up a batch, who cares!” says Sutherland. “You may not want to serve it to guests, but you can certainly eat it yourself.
“The most important thing is not to be afraid,” she adds. “Keep trying until you get it right.”
Once you’ve done that, you can enjoy nearly fresh homegrown vegetables year-round.