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Freezing your bounty of fruits and vegetables

Prairie Fare: As gardens hit high gear, it’s time to preserve some of the excess for the coming winter

Freezing is an easy, convenient and affordable way to preserve fruits and vegetables.

In fact, when fresh produce is frozen shortly after being harvested, it can contain more nutrients than fresh vegetables that have been shipped long distances or stored in warehouses or on retail shelves. If you have a garden, a neighbour with surplus edibles or some way to access affordable, fresh produce, now’s a great time to get it and freeze it.

Freezing helps preserve flavour, colour and nutrients, but it does not kill microbes, it just inactivates them while they’re frozen. Once thawed, the microbes become active again, so treat frozen food like any other perishable food.

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Frozen food remains safe to eat as long as it stays at -18 C (0 F). As long as food is kept at that temperature, the only concern is food quality. To maintain the best colour, flavour and texture for the longest time possible, it’s important to control for the following factors.

Food quality

Select only fresh, firm, high-quality produce and freeze within six to 12 hours of harvesting or purchasing. Overripe, bruised or produce stored in the fridge for several days will result in low-quality frozen food that will deteriorate more quickly.

Moisture

Excess moisture in frozen food and in the freezer (caused from opening the freezer or adding warm containers to the freezer) will cause ice crystals to form. While not a food safety issue, these ice crystals will cause texture and flavour losses. To reduce moisture, cool blanched vegetables completely before sealing and dry fruits and vegetables as much as possible before placing in freezer containers.

Air

Frozen food exposed to air will dry out over time. The greyish-white dry spots that develop are known as freezer burn. These do not make food unsafe to eat, but they do impact flavour, colour and texture. To minimize freezer burn, use freezer-grade containers to prevent the penetration of air and moisture. Use the right-size containers that provide enough space for expansion but not too much space to trap extra air. If using freezer bags, remove as much air as possible before sealing. Try inserting a straw and sucking out the air for an almost vacuum-sealed package.

Enzymes

For long-lasting quality vegetables, blanching (boiling vegetables for a very short time) is highly recommended to stop the enzymes that age vegetables. Freezing alone does not stop these enzymes. Without blanching, vegetables will continue to age and within three months their colour, taste and texture will be noticeably different. While these enzymes are present in fruit as well, their effects are not noticeable and therefore blanching is not necessary for fruit.

Time

Time is a threat to the quality of frozen food at various stages starting with when produce is harvested to how long it is kept in the freezer. For best results, pick and process as soon as possible, freeze in small quantities so it freezes quickly, and eat it within six to 12 months.

How to freeze and blanch vegetables

Many people and websites say you don’t need to blanch vegetables before freezing. That’s true only if you plan to use your frozen vegetables within three months or just aren’t that picky about the quality or flavour of your vegetables.

Blanching is important for all but a few vegetables like peppers, tomatoes, shredded zucchini and diced winter squash. Luckily, blanching is an easy step to add when freezing vegetables.

Follow these steps:

  • Wash, drain, sort and cut vegetables as desired.
  • Bring large pot full of water (one litre per 250 ml veggies) to hard boil.
  • Add vegetables and return to boil.
  • Boil vegetables for recommended time (see chart).
  • Shock vegetables in cold, icy water to stop the cooking process.
  • Drain and dry well.
  • Place on tray to freeze separately; freeze for one to two hours.
  • Add to freezer container, remove air and seal. If using rigid containers leave a two-cm space for expansion.
  • Label and freeze.

How to freeze fruit

There are three common methods for freezing fruit.

Dry Pack – freeze without any sugar.
Sugar Pack – freeze with a coating of dry sugar (about 125 ml sugar per litre of fruit).
Syrup Pack – freeze with a liquid sugar solution (about 250 ml sugar dissolved in one litre water).

Adding sugar before freezing helps soft or sliced fruits like apricots, strawberries, plums or cherries keep their colour and shape better. The Dry Pack, shown below, is the quickest and easiest method and offers the most flexibility for using frozen fruit.

  • Wash fruit under running water or quickly dipping in a bowl of water, do not soak.
  • Drain, sort, trim and cut as desired.
  • Place fruits that darken (apples, pears, apricot, peaches, etc.) in an anti-browning solution (60 ml lemon juice in one litre water) to prevent browning while preparing big batches.
  • Drain and dry well.
  • Place on tray to freeze separately; freeze for one to two hours.
  • Leave space for expansion.
  • Label and freeze.

The only threat to the safety of your frozen food is rising temperatures. Keep a thermometer in your freezer and ensure it stays at -18 C (0 F). If your freezer ever loses power, keep the freezer closed. A full freezer will keep food frozen for 48 hours, a half-full freezer will keep food frozen for 24 hours. If the outage lasts longer than that, transfer food to coolers with ice or move it to a friend’s freezer. Once power is restored, check your food. Any food that still has ice crystals or is refrigerator cold, can be refrozen. Any food that has thawed and has been at room temperature for more than two hours should be discarded.

Following these best practices will have you enjoying your frozen fruits and vegetables until next year’s crop is ready to harvest.

Just don’t lose them in the bottom of the freezer and forget to eat them throughout the year!

About the author

Contributor

Getty Stewart is a professional home economist, speaker and writer from Winnipeg. For more recipes, preserves and kitchen tips, visit www.gettystewart.com.

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