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Tag: Food Preservation

Tips for Canning Tomatoes

Posted on by Karen Blakeslee
tomatoes
Photo: USDA Flickr

Many gardeners plant tomatoes and they are starting to ripen. Preserve them by canning, freezing or dehydrating to use later in many recipes. While it is fun to make salsa, spaghetti sauce or even a barbecue sauce, having basic options such as whole tomatoes, tomato juice or tomato sauce allows you to use tomatoes in many more recipes.

Here are some reminders about tomatoes:

  • Although tomatoes are usually considered to be acidic in flavor, most have pH values slightly above 4.6, which makes them a low-acid food. As such, tomato products must be acidified to a pH of 4.6 or below with bottled
    lemon juice, vinegar, or citric acid. Properly acidified tomatoes can be safely processed in a boiling-water canner or pressure canner as an acid food. Learn how to acidify tomatoes in Preserve it Fresh, Preserve it Safe: Tomatoes.
  • Pressure processing instructions are equivalent in heat treatment to water bath processing. Caution: Both methods require acidification. There are no recommendations for processing tomatoes without acidification. The chart in the above publication provides the options for acidification.
  • Tomato-based recipes for products such as salsa, barbecue sauce, ketchup and others will also include added acid. Do not reduce the amount of added acid in these recipes.
  • Tomatillos can be substituted for tomatoes in the same amount stated in a recipe, such as in salsa.
  • Salt is for flavor only and can be omitted, if desired.

Tomatoes

The Science of Freezing Food

Posted on by Karen Blakeslee
Freezing Food
Photo: Newell Brands, Inc.

Freezing food is an easy way to preserve high quality food with maximum nutritional value. But food in the freezer doesn’t last forever as changes will occur during storage.

Freeze food as soon as possible after harvest to stop chemical compounds, called enzymes, that cause deterioration and spoilage. Enzymes are naturally in foods and must be inactivated to stop loss of color and nutrients, as well as flavor changes. Blanching vegetables is an important step to inactivate enzymes. In fruit, color changes are prevented by using pure ascorbic acid (vitamin C) or a commercial ascorbic acid mixture such as Fruit Fresh®.

Because of high water content in fruits and vegetables, texture changes occur. Water expands when frozen which ruptures food cell walls. Freezing food quickly will help reduce texture damage. Don’t overload the freezer with unfrozen food and keep the freezer as cold as possible, at least 0°F or below.

Over time, food loses moisture during freezing which leads to freezer burn. Use packaging designed for freezing to reduce this problem.

Freezing does not kill bacteria, it only slows it down. When food thaws, any bacteria present will become active again. Always inspect food and packages  carefully before use.

Source: https://extension.umn.edu/preserving-and-preparing/science-freezing-foods

Why Does Home Canned Corn Turn Brown?

Posted on by Karen Blakeslee
Photo: USDA ARS

If sweet corn browns during canning, it usually means that the temperature required for canning is too high for the sugar levels in the corn variety.  This carmelization has become more of a problem as newer varieties of corn get sweeter and sweeter. You cannot, however, safely reduce the heat or processing time needed for canning corn; you can freeze that corn or find a locally grown variety that is recommended for canning. Though not an immediate safety concern, you might want to consider refrigerating these jars and/or consuming them more quickly since they may not maintain the best quality for long.

Learn more about preserving corn at Preserve it Fresh, Preserve it Safe: Sweet Corn.

Source: https://nchfp.uga.edu/blog/corn-ucopia

Why do Home Canned Green Beans Get Cloudy Liquid?

Posted on by Karen Blakeslee
Canned green beansPhoto: KSRE
Canned green beans Photo: KSRE

There are several reasons cloudiness can occur.

  1. The beans may be too mature which makes them too starchy.  The starch settles out of the food during canning. This is a quality issue.
  2. Minerals in hard water can give a cloudy appearance. This is a quality issue.
  3. Using table salt instead of canning salt.  Table salt contains anti-caking agents that can cause cloudiness.  This is a quality issue.
  4. Finally, it could be spoilage due to improper heat processing.  Do not consume them in this case. Plain green beans MUST be pressure canned because they are a low acid vegetable. When not processed properly, Clostridium botulinum could cause foodborne illness.

Learn how to safely preserve green beans in Preserve it Fresh, Preserve it Safe: Beans.

Source: https://nchfp.uga.edu/how/can/general-information/causes-and-possible-solutions-for-problems-with-canned-food

 

Shelf Life of Mrs. Wages Mixes

Posted on by Karen Blakeslee

Mrs. Wages makes several packaged mixes to help make home canning easy and quick. All of their products for canning use the water bath canning method. But do the mixes have a shelf life?

Mrs. Wages recommendation:

“On the side of every Mrs. Wages® pouch is an 8 digit code that you can use to determine when the product was produced, and you will find it stamped into packet, for example B2181A23. The B identifies the facility that produced the mix. The number, which follows, represents the last digit of the year the mix was produced, e.g., a 2 would indicate 2012. The next three numbers indicate which day out of 365 days in the year, the mix was produced. So if the number is 181, it means the product was mixed on June 29th as this is the 181st day of the year. The final 3 digits are used by Kent Precision Foods to indicate the batch code. For optimal performance, we recommend using Mrs. Wages® Pickle, Tomato, Fruit mixes and Fruit Pectins within 24 months of the day and year, it was produced.”

Source: https://www.mrswages.com/canning/frequently-asked-questions/

Canning on Portable Burners

Posted on by Karen Blakeslee

Portable, or stand alone, burners might be a good option for those who have a smooth cooktop and the stove manufacturer states that canning should not be done because of the high heat, heavy canner weight, and possibility of cracking the stove top.

There are many options for portable burners, but not all of them are appropriate for home canning equipment. Check the burner manufacturer’s specifications and directions to make sure the burner can withstand canning. Some basic guidelines include:

  • The burner must be level, sturdy, and secure enough to hold large canners filled with water and jars of food.
  • The canner diameter should not extend more than 2 inches from the burner.
  • For electric burners, the wattage should be comparable to a typical large household range burner. Most household range burners are at least 1,750 watts or more.
  • The burner housing should hold up to high heat for long periods of time, without damaging countertops.
  • At least one pressure canner manufacturer does not recommend using an outdoor heat source, such as a turkey fryer burner.
  • Burners that produce more than 12,000 BTUs can damage your canner.
  • Always follow manufacturer directions.

Learn more at https://nchfp.uga.edu/newsflash.

Canning Previously Frozen Food

Posted on by Karen Blakeslee

Sometimes, freezing is the quickest way to preserve fresh food from the garden or farmers market. But can that frozen food be used in canning? In many cases, it depends on the food itself. Freezing will change the texture and soften the food upon thawing. This will cause the food to pack into jars differently compared to fresh food.

Canned tomatoes
Canned tomatoes, University of Georgia

For example, frozen tomatoes could pack into jars differently than freshly prepared tomatoes and cause overfilling of jars since they are softer when thawed.  Overfilling can result in under-processing (and therefore possible spoilage on the shelf) and possibly under-acidification with more tomatoes in the jar than expected.  Process times are dependent on food being prepared as described in the preparation steps printed with the time.  The best recommendation is to use these tomatoes in something that is well cooked like stewed or crushed tomatoes or make tomato juice or sauce.

The only way to consider doing this with tomatoes is to freeze the tomatoes for a very short time of just a few weeks at most, without any other added liquid or ingredients.  Then when you have enough, thaw them completely and use all the tomatoes and their juices in the pack to make the crushed tomatoes with the hot pack method.

Unsweetened frozen and thawed fruit can be used in place of fresh fruit in jams and jellies. For best results, measure frozen fruit before thawing. Learn more tips about safe changes to tested canning recipes at https://www.ndsu.edu/agriculture/sites/default/files/2024-03/fn2102.pdf.

Source: Dr. Elizabeth Andress, Professor Emeritus, University of Georgia

 

Canning in Half-gallon Jars

Posted on by Karen Blakeslee

Half-gallon sized canning jars are available, but they are not recommended for canning many foods. In fact, the only products recommended by the manufacturer to can include apple juice and grape juice ONLY in a boiling water bath canner.

There are no other research-tested processes for half-gallon jars. Boiling water processes for other foods for jars larger than those published with recipes (usually pints and/or quarts) cannot be extended by any formula to a larger jar.

Historical canning resources may reference the use of half-gallon jars. However, these are not currently accepted or endorsed by the USDA, Cooperative Extension, or U.S. canning jar manufacturers.

Learn more from Jar It Right! Choosing and Using Canning Jars from the North Central Food Safety Extension Network.

https://nchfp.uga.edu/faqs/general-canning/category/faq-canning

Cheer for Cherries!

Posted on by Karen Blakeslee

preserving cherriesIt’s cherry season and they are a treat in many recipes. They can be preserved in many ways also!

Freezing, dehydrating and canning are all options for cherries. Frozen cherries can be eaten as snacks, mixed into oatmeal or used in desserts. Dehydrated cherries are great snacks, add to a leafy green salad, or mix into a trail mix. There are many options for canning cherries such as jam, jelly, pie filling, or just plain cherries canned in water or a sugar syrup. Plain cherries can be canned with or without the pits.

Learn more about canning cherries from Preserve It Fresh, Preserve It Safe: Cherries.

Canning on Portable Burners

Posted on by Karen Blakeslee

If you have a smooth cooktop and the manufacturer says not to can on it, then you might find yourself looking for an alternative. The alternatives for canning (if you have one of these no-canning recommended smooth cooktop ranges) are either to purchase and install a permanent set of electric coil or gas burners as a range top (without an oven) or to purchase a portable electric coil or gas burner.

And that is where important decisions come in to play.  An installed range top requires the utilities to support it and can be quite expensive as a second range top. As for portable burners, they are not all alike and not all portable burners are appropriate for canning.  First of all, check the burner manufacturer’s specifications and directions or contact their customer service department for more specific information about the appropriate use of a particular burner for canning.

Also, most canner manufacturers do not recommend using turkey fryer burner because of the intense heat and physical safety.

Learn more from the National Center for Home Food Preservation.

 

Reference to any specific commercial products, process, service, manufacturer, or company does not constitute its endorsement or recommendation. Paid for by Kansas State University