Mastering Food Preservation: Freezing Fruit

The fifth session of the Master Food Preserver Program was timed to coincide with raspberry season. Unfortunately, an infestation of Spotted Wing Drosophila decimated the local farmers’ crop. Fruit growers are keeping a watch on this new pest as it spreads throughout the region, the damage it can inflict posing a serious threat. This insect attacks a wide range of fruit as they ripen, with late summer and fall fruit of ever-bearing strawberry, late season brambles (raspberry and blackberry), late blueberries, and colored grapes the most vulnerable. Peaches seem to be less so, at least for the moment, and they served as a substitute in this evening’s recipes for freezing fruit.

The evening’s slate of activities: Herbal Vinegar (Part II), Low Sugar Peach Freezer Jam, Freezer Peaches Packed in Syrup, and Freezer Applesauce.

The herbal vinegar we made several sessions ago had been left to sit for several weeks. It takes at least 10 days for most flavors to develop, and about 3 to 4 weeks for the greatest flavor to be extracted. We strained out the sage and rosemary from the now infused vinegar, and reprocessed it in a boiling water bath for longer-term storage.

The peaches were preserved two ways — as a freezer jam and frozen packed in syrup. First, the peaches needed to be peeled, and were scored and blanched to make the process easier. Peach slices were packed in a 20% sugar syrup; 40% is recommended but we were short on sugar that night and made do with a lighter syrup. Some headspace was left between the packed peaches and the top of the freezer containers, with a crumpled piece of wax paper added on top to keep the fruit submerged.

The other half of the peaches were made into a low-sugar freezer jam, another way of preserving peaches when time is short or the weather’s too hot to process by canning. Freezer jams tend to be less firm than ones that are cooked and canned, but retain more of the fruit’s texture and fresh taste.

Like freezer jam, freezing applesauce is an alternative to canning it. Simply wash, peel, core and slice the apples, and cook down until the desired consistency is reached. To keep fruit like apples and peaches from browning, place the slices in a holding solution made of 1 teaspoon ascorbic acid (Vitamin C) mixed into 1 gallon water, until ready to prepare. Citric acid or lemon juice solutions, and sugar syrup may also help to control browning, but not as effectively as ascorbic acid.

I now keep a thermometer in all of my freezers to make sure they’re at 0°F or lower, the temperature that frozen fruits and vegetables should be stored at for best quality and length of time. It’s recommended that 2 to 3 pounds of food per cubic foot of freezer space can be added to a freezer within a 24 hour period. More than that, and the food may not freeze quickly enough.

We often lose power here in Northern New England due to winter storms, and the most common question is whether thawed food can be refrozen. Foods can be refrozen only if at least one of these two conditions are met: 1) Foods have only partially thawed and still have ice crystals in the package; 2) The freezer temperature has remained at 40°F or below. Before using, check to see that color and odor of the food are good; quality of the food will be lower. One last freezer tip — keep an ice cube in a sealed container placed in the freezer; if the electricity goes off for any length of time, the melted ice cube will serve as an alert that there’s been a loss of power.

Recipes & Resources
– Preserving Food: Flavored Vinegars
Low-Sugar Freezer Jam
– Freezing Fruits (Frozen Peaches Packed in Syrup)
Let’s Preserve: Apples (Freezer Applesauce)
Preserving Food: Freezing Prepared Foods
Video: Defending Against Spotted Wing Drosophila

This series of posts follows the Master Food Preserver Program being offered through the University of Maine Cooperative Extension.

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2 Responses to Mastering Food Preservation: Freezing Fruit

  1. Claire says:

    I love reading about the food preservation classes! Today I made and canned tomato sauce for the first time by myself. There have been no explosions, broken glasses or burnt arms so I consider it a success.

    • leduesorelle says:

      Hi Claire, thanks for visiting and congratulations on your first attempt at canning tomato sauce! There’s a steep learning curve when first starting out canning, but it gets easier with practice. I was so scared of botulism my first year that I made sure that everything was boiled for 10 minutes before I’d eat it…

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