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Tag: Freezing

Safety of Canned Foods that Freeze in Winter

power outageRecent cold weather has created challenges for all of us. Power outages can lead to many problems. If you have canned foods, either home canned or commercially canned, in a storage location that froze, what can you do?

Check for broken seals or seams in metal cans or broken glass in home canned foods due to expansion of the food and liquid inside the container. If all are intact, they can be saved. Thaw gradually and store at room temperature.

For commecially canned foods, if seams are broken, that can lead to contamination and be unsafe to eat. Discard these cans.

For home canned foods, discard broken glass containers. If the lid became unsealed, and the jar thawed to room temperature, discard these too.

If a glass jar became unsealed but is still frozen, this can be safely used immediately or transfered to a new container and stored in the refrigerator or freezer.

During cold weather, wrap jars or cans in paper and cover with blankets to insulate them. Another option for vulnerable storage locations is to prop open pantry or cupboard doors to allow warm air inside.

For more information on food safety during power outages, see https://www.ksre.k-state.edu/foodsafety/topics/disaster.html.

Source: https://extension.oregonstate.edu/food/preservation/safety-canned-food-freezes

Freezing Food for the Fair

Fair judging
Kansas State Fair, Photo: KSRE Flickr

To help save time and stress at county fairs, prepare food entries early and freeze them.  Most baked goods freeze well and can still be blue ribbon quality.  This includes cookies, yeast and quick breads, and cakes.  Here are some tips:

  • Bake the product as usual. Cool completely!  This helps prevent condensation inside the wrapping and development of ice crystals.
  • Use moisture-vapor resistant packaging. This includes freezer-safe plastic containers or bags, heavy-duty aluminum foil, and rigid containers.
  • Separate layers of cookies with wax paper or parchment paper.
  • If a cake or bread is to be frosted, freeze the product only and frost after it is thawed.
  • Make pie crusts ahead of time and freeze. Freezing whole prepared pies can cause the filling to soak into the crust.
  • Thaw all baked goods in the freezer packaging. They can be thawed at room temperature.  Remove from the freezer the night before the fair.  Once thawed, repackage into the proper packaging according to your fair rules.

Source:  Univ. of Georgia, www.uga.edu/nchfp/publications/uga/FreezingPreparedFoods.pdf

Source:  Univ. of Georgia, www.uga.edu/nchfp/publications/uga/FreezingPreparedFoods.pdf

 

Blanching Vegetables

Blanching vegetables is defined as scalding vegetables in boiling water or steam for a short time. It is a critical step in freezing vegetables to protect flavor, color and texture.

Blanching also helps remove dirt, organisms, brightens up the color, and helps preserves some vitamins. It stops the natural enzymes in the vegetables from continuing to change flavor, color and texture. Underblanching can cause the enzymes to become more active and is worse than no blanching at all.

The blanching process is quick and each vegetable has its own blanching method and time.

Learn more about blanching and a list of blanching times for many vegetables from the National Center for Home Food Preservation.

Freezing Yeast Dough

bread dough
Bread dough
Photo: Colorado State University Extension

To save time during the holidays, or any time of year, prepare yeast dough ahead of time and freeze into dough balls for rolls to bake later. The trick is using a dough with extra yeast because slow freezing can damage yeast.

According to Fleischmann’s Yeast, it is best to use dough recipes developed for freezing. These recipes are high in yeast and sugar and low in salt. It is recommended to use bread flour to help maintain bread structure. After preparing and kneading the dough, shape into rolls or flatten into a disk and wrap airtight. The dough can be frozen up to four weeks. When ready to use, thaw at room temperature or slowly in the refrigerator. Once thawed, shape, let rise, and bake as directed.

Some examples of freezer dough recipes include:

https://www.fleischmannsyeast.com/recipe/freezer-pizza-dough/

https://www.fleischmannsyeast.com/recipe/master-bread-dough/

 

Foods that Do Not Freeze Well

frozen lettuce
Frozen lettuce
Photo: NCHFP

Gardens are bursting with bountiful produce this time of year. While many fruits and vegetables can be frozen, there are some that do not freeze well.

This is due to the high water content within the produce. Some produce that does not freeze well include cucumbers, lettuce, radishes, parsley, celery, and raw cabbage. They will become limp, watery, and develop an oxidized color, aroma and flavor. In some herbs and seasonings, the flavors may become strong and bitter. Irish potatoes, baked or boiled, tend to become watery and mealy in texture.

If cucumbers or cabbage is pickled or marinated and then frozen, they can be frozen in that form. It is best to use them partially frozen to help retain some texture.

Some other foods that do not freeze well include cooked eggs, sour cream, custards, and mayonnaise or salad dressing.

Learn more at the National Center for Home Food Preservation.

Why Blanching is Important Before Freezing Corn

corn
Blanching corn helps improve the texture and color during freezing.

Blanching is a process in which vegetables are lowered into boiling water for a specific time. The vegetables are subsequently dropped into ice water to quickly cool, then dried and placed in freezer containers. Freezing slows down enzyme processes, but it doesn’t stop them. Blanching is recommended to assure your corn will taste as fresh as possible after they have been frozen.

That’s because blanching stops enzyme activity. Enzymes in produce help it ripen, and continue to do their work even after the produce has been picked. By stopping the enzyme action, blanching prevents the produce from becoming overripe. Blanching also helps retain color, flavor, texture and nutrients. Blanching also helps remove dirt and small organisms from the produce.

It is important to look up the specific amount of time corn needs to be blanched and follow those guidelines. If corn is under-blanched, it can actually speed up the enzyme processes. If corn is over-blanched, the nutritional value, flavor, color and texture can be negatively affected.

Learn more in Preserve it Fresh, Preserve it Safe: Preserving Sweet Corn.

 

Preserving Eggplant

Eggplant
Photo: USDA Flickr

Freezing is the only way to preserve eggplant. There are no canning instructions.

Use frozen raw eggplant in dishes where it does not need to stay firm such as soups, stews, sauces, and dips.

Cooked eggplant, such as roasting, may be frozen to use in dips or sauces.

Consider the age, size, and variety of eggplant you are using. Small thin varieties may have tender skin and not require peeling. Older larger varieties with more seeds may have a bitter taste; those slices may be salted to draw out bitter juices.

Source: Penn State University Extension Food Preservation

 

The Science of Freezing Food

Freezing Food
Photo: Newell Brands, Inc.

Freezing food can be quick and convenient. But there is a lot of science behind how food freezes that can affect the outcome.

After harvesting fruits and vegetables, chemical changes still occur due to enzymes naturally within the food. These enzymes can change color, texture, flavor, and some nutrients. To stop enzymatic changes, there are key steps to take.

For most vegetables, blanching is effective to inactivate enzymes. This exposes the vegetables to boiling water or steam for a brief amount of time, then rapidly chilled in ice water. Blanching is essential for high quality vegetables. It also helps destroy any microorganisms. Blanching time varies by vegetable.

For light colored fruit, such as peaches and apples, enzymes can cause browning and loss of vitamin C. Instead of blanching, fruit can be treated with ascorbic acid (vitamin C) to interfere with the chemical reaction that causes the color changes. Use pure ascorbic acid or commercial ascorbic acid mixtures.

Texture of frozen food can depend on the rate of freezing. Don’t overload your freezer as that will slow the freezing process and result in poor quality food. Typically, freezing 2 to 3 pounds at a time is best.

For more information on freezing, see the National Center for Home Food Preservation website.

Source: University of Minnesota Extension

What is Freezer Burn?

Freezing
Plastic freezer boxes work well for freezing fruits or vegetables.
Photo: University of Georgia

Have you opened a frozen food to find it has dry, grayish/brown spots on the surface? This is freezer burn. While not harmful, it’s not very appetizing. This defect is most notable on frozen meats.

Freezer burn happens when food is not adequately wrapped to remove oxygen, which has a bleaching effect on the food surface. It cause poor texture, color, flavor, and aroma.

To prevent freezer burn, package food tightly in packaging designed for freezing. Remove as much air as possible. Check your freezer temperature is zero degrees F or lower to help freeze food fast. If using freezer containers, crumple a piece of waterproof paper on top of the food to help minimize headspace. This helps prevent freezer burn, ice crystal formation and keeps food pieces from drying out.

Source: Understanding the Process of Freezing, Penn State Extension Food Preservation

 

Packaging for Freezing Food

Refrigerator-Freezer StorageA walk down the food packaging aisle reveals many choices for storing food. Which ones are best for freezing food? Not all of them are the same.

For freezing, look for the word “freezer” on the package. Plastic containers for freezing are made of thicker material to resist tearing, moisture migration and protect from off-flavors and odors. Rigid plastic containers for freezing are also good choices. Freezer paper is best for wrapping meat products. Use a freezer safe tape to hold the package together.

Always label and date the package so you know the contents and how long it has been in the freezer.

Never use packaging not designated for food storage, such as garbage bags.

For more information, see Preserve it Fresh, Preserve it Safe—Freezing.

Safe Food Storage: The Refrigerator and Freezer—K-State Research & Extension