4. Blanch greens: Use one gallon water per pound of prepared vegetables. Put the vegetable into vigorously boiling water. Push down with tongs. The water should return to boiling within 1 minute, if it doesn’t, you are using too much vegetable for the amount of boiling water. Start counting blanching time as soon as you place the vegetables into the boiling water. Cover with a tight fitting lid and keep heat high for the time given in the directions for the vegetable you are freezing. In this case, 3 minutes. (Below is a chart of times for various vegetables)
What & Why? Blanching (scalding vegetables in boiling water or steam for a short time) is a must for almost all vegetables to be frozen. It stops enzyme actions which can cause loss of flavor, color and texture.
Blanching cleanses the surface of dirt and organisms, brightens the color and helps retard loss of vitamins. It also wilts or softens vegetables and makes them easier to pack.
Blanching time is crucial 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.
5. Shock greens: Shocking vegetables is the process of plunging them into ice water to immediately stop the cooking process. This preserves the color, nutrients and flavor.
Fill clean sink basin or large bowl with fresh water and a lot of ice. Using tongs or slotted spoon to remove boiling vegetables, immediately transfer to ice bath and gently stir and submerge allowing them to cool for about the same time as they cooked.
6. Drain: I like to gently squeeze the water out of the chard so that I’m not freezing a lot of ice crystals. Here, I laid multiple layers of paper towel on my counter top and placed squeezed bundles of greens to drain. I measured the piles based on serving sizes. I used about 1 handful per person to amount to a serving. I bagged the greens according to the servings I would typically use for a given meal or recipe.
7. Bag: A lot of people like the Foodsaver system, but I don’t have one yet. I used Ziploc freezer bags and squeezed out as much air as possible. Make sure to label and date your packages! Greens can be kept frozen for 8 to 12 months.
Here’s a handy chart for cooking times: National Center for Home Food Preservation