But my jars sealed…

Often when people ask if their canned food is safe even though they know or have been told they processed them unsafely, they end by saying “the jars sealed”.  Or, they are finding really old home canned jars of food they forgot about, or found, when cleaning out a relative’s home. “They’re sealed so shouldn’t they be safe?” Here is short posting to say that a sealed jar is not a sign of food being processed safely!

A vacuum seal that forms on a canning jar after processing only means that there is a sealed_lidvacuum holding the lid on. To create a vacuum requires enough heat produced in the contents and the lid and then a cooling process that draws the vacuum.  The heat required to form a vacuum seal with today’s canning lids is much less than the heat needed to sterilize most foods.  Killing of spores of C. botulinum bacterial spores in low-acid foods, for example takes much more thorough and severe heating throughout the food mass than the heat needed to sufficiently warm the lid and headspace for vacuum to form after cooling.

Even killing of harmful bacteria like E. coli or others of concern in acid foods would take more heating of the jars of food than that needed to cause a vacuum seal to form during cooling. Enough heat has to get distributed throughout all parts of the mass of food in the jar to get to wherever the bacteria might be.

If a food was processed safely, a vacuum seal then needs to be maintained during storage of canned foods on the shelf to keep the food safe. The vacuum seal prevents food from being re-contaminated (and drying out). But a vacuum seal by itself is not a sign that the food inside was processed correctly to make the food safe.


It’s Peak Apple Time

Fall weather brings the best fresh apples in bushels.  While we are in a season of peak applechutneysmallapple production in many states, you might consider preserving some specialties that will add variety to menus throughout the year.  Apples can be dried, made into applesauce or apple butter, or even made into a delicious apple pear jam. Those who treasure the crispness of fresh apples will not be impressed by soft canned or frozen apple slices, but they can be preserved by those methods, also.

Whether you are buying apples by visiting the nearby orchard, the grocery store or market, or even picking apples from your own backyard, choose the preservation method that is best for your apple variety. Varieties that are good for freezing include: Golden Delicious, Rome Beauty, Stayman, Jonathan and Granny Smith. Varieties that are good for making applesauce and apple butter include: Golden Delicious, Rome Beauty, Stayman, Jonathan, Gravenstein and McIntosh. Red Delicious apples are best eaten fresh. They do not freeze or cook well in most opinions.  There are so many newer varieties in the last few years, it will take some time to get this list updated, but it is a starting place for your choices.

When selecting your apples for preserving, choose apples that are free of defects, such as bruises, skin breaks and decayed spots. Little brown spots appearing solely on the skin of the apple, called “russeting,” does not affect quality of the tissue underneath. Beware and on the lookout for browning or broken skins that are evidence of actual spoilage such as rotting or mold.

If making applesauce, apple butter or dried slices with your apples, use them as soon as possible after harvest. If any apples must be stored, keep them in a cool, dark place. They should not be tightly covered or wrapped up; a perforated plastic or open paper bag, basket or wooden crate are good choices. If kept in the refrigerator, apples should be placed in the humidifier compartment or in a plastic bag with several holes punched in it (or in a zipper-type vegetable bag). This prevents loss of moisture and crispness. Apples should not be placed close to foods with strong odors since the odor may be picked up by the apples.

Here are some options to prepare for and choose from in preserving your apples:

Making and canning a flavorful applesauce:

Making and canning a tasty, robust apple butter:

For those who want a no-sugar added apple butter:
(ours was developed  for sucralose as a sweetener but no sweetener is necessary)

Drying apple slices or rings:

Combining the best of fall fruits in tasty pear-apple jam:

Making old-fashioned, pretty crabapple jelly:

Canning a special, spicy gift-quality apple chutney: apple chutney

And if you like the option of a spicy pickled profile, also check out this apple relish:

And, for all those extra apple slices to save for pies and desserts later in the year, freezing:

For more information on canning and freezing methods, including packaging choices and headspace for freezer containers, see general sections on these topics available from the National Center for Home Food Preservation at the University of Georgia, https://nchfp.uga.edu.


Jar Size Choices Have You Frustrated?

I am often asked what the process time should be when home canning in a jar size not listed with a food.  Well, there is not just a formula to apply to change assorted empty canning jarsprocess times for sizing up or down a jar. (If there was, it would be easier to offer a wider range of jar sizes for all products.)  Different foods heat up at different rates and require different adjustments.

Therefore, the general rule of thumb is if you want to use a smaller jar than one listed with a tested process, use the process time for the next size larger jar than you have.  For example, if a procedure only lists pint jars as the smallest choice, and you want to use half-pint jars, you use the process time for pint jars. The product is likely to be even softer when processed in this manner, but it is the only choice for safety and you need to take that into consideration if desiring to use smaller jars. Do remember if you use too small of a jar compared to one studied, say a 4 oz instead of a pint jar (16 oz), you could end up with a very overcooked product and it may not be desirable to do so, even if safe.

Another example, since there are some 24- and 28-ounce jars now manufactured for home canning: These are between pint and quart size jars, so you would use the quart process time if one is available.  If there is only a pint and/or half-pint process listed with the procedure, then there is no tested process available for a 24-, 28- or quart size jar. So this leads to the next situation, there is no way to offer a known safe process for a jar larger than the largest one studied. If the largest jar size recommended is a pint jar, then there is not a formula to be able to say how to increase the process time for a larger jar.

To come up with a minimally safe and still optimum as much as possible process, one has to have the actual heat penetration (heat tracking data) from the food being heated in the jar size to be recommended in order to calculate a specific process to the jar size and type.  For more about how process times are researched, especially for all low-acid foods, there is more description here: https://nchfp.uga.edu/publications/nchfp/factsheets/heatprocessingbackgrounder.html

As you choose jars, in addition to size, please remember we recommend jars properly tempered for the temperature extremes of home canning, as well as those with closure systems recommended for home canning so you obtain good vacuum seals using recommended processing procedures. These jar choices will also be a limiting factor in sizes for which you need process times.

Please be safe in your home canning choices. The research-based processes available may seem very limiting for what you want to do; however, there has been little public funding for researching new recommendations in a long time and there are few labs set up and staffed to do home canning research. This often means when something new can get researched, there will not be multiple jar sizes tested.


Vidalia Onions Are In!

It’s May in Georgia and that means Vidalia onion season. While these are famous for their sweet flavor, there are numerous varieties and colors of onions. Onions are used in many unique, flavorful condiments – relishes, salsas, pickles, and jams to name some of the most common. Sometimes we just need to preserve onions themselves.

I’m often asked why our University of Georgia So Easy to Preserve book does not have the option of freezing diced onions. Well, I can’t explain why it was never in the early editions and we just haven’t been able to issue a whole new edition since the 6th edition in 2014. This is one of the drawbacks of a large book that you don’t revise or reproduce for one issue at a time.  We have had this additional option on our Freezing Onions page at the National Center for Home Food Preservation for the past few years:

Peeled, washed onions can be diced or chopped (1/4-1/2 inch pieces suggested) and frozen without blanching. If you have room in your freezer, it is best to spread the pieces out on a clean cookie/baking sheet in a single layer.  When they are frozen (hardened), promptly remove from the tray and package air-tight in freezer bags or containers while they are still hard.  This keeps pieces separated in their freezer packaging enough that you will be able to remove only as much as you want at a time.  If they are all put into the bag or container at room temperature, they will freeze into one large mass and not as separate pieces. If you are going to remove part of the amount frozen at a time versus using the whole amount, it works best to use freezer bags, so you can push the air out when you re-seal the remaining frozen pieces.  In a hard container, the air left in the box/jar as you keep removing some is not good for quality and can cause freezer burn (drying out of the food).

The National Center for Home Food Preservation also has this webpage with more ideas and tips for preserving onions: https://nchfp.uga.edu/tips/summer/onions.html.  At the end of it, there are links to our Canning Relishes factsheet with several that emphasize onions and others that contain some onion content.