canning

10 Rules for Safe Canning

By Diane Wright Hirsch, MPH
Senior Extension Educator/Food Safety

home canning with tomatoes
Photo: Diane Wright Hirsch

Even though some may feel home canning has gone the way of the dinosaurs, I regularly get questions posed to me by newbie and experience canners alike. Some want to know how to can tomatoes without potentially killing a loved one. Others want to know if there is anything new in the canning pipeline.

It seems as if more people are gardening these days so that they can have more control over their produce supply—they can grow what they like and minimize the use of chemical pesticides or fertilizers. A happy consequence of a successful garden is a bountiful supply of zucchini, tomatoes and peppers—maybe too bountiful! As a result, the gardener must now become a food processor. Home canning is not difficult, but, it IS important to do it right. Here are ten rules for canning to help you in your pursuit of a safe home canned food supply—whether you have been canning for years or this is your first time.

1) Make sure your jars/lids are in good shape.
 Use (or re-use) canning jars manufactured for home canning. Check for cracks or chips and throw out or recycle any jars that are not in good shape.
 Be sure the jar rings are not dented or rusty.
 Buy new jar lids. The sealing compound can disintegrate over time, especially in damp basements, so make sure that your supply is new or no more than one year         old. Do not reuse old lids. (If you still use rubber jar rings, these CAN be reused unless they are dry and/or cracked, though these jars may be more prone to failed seals.)

2) Use up to date canning guidelines. With the exception of jams and jellies, recipes that are older than 1996 should be relegated to the family album. A great resource for up to date guidelines and recipes is the National Center for Home Food Preservation at: www.uga.edu/nchfp. This site is the United States Department of Agriculture (USDA) approved site for home food preservation information. Go there and check out the latest recommendations. They are also great about addressing some questionable practices that are introduced over the years, such as canning food in the oven or canning bread in a jar.

3) Choose the right canner for the job.
 Water bath canners are for jams, jellies, relishes, pickles, fruits such as apples, apple sauce, peaches and tomatoes.
 Pressure canners are for all other vegetables, soups, meats, fish, and some tomato products, especially if they contain large amounts of low acid vegetables such as peppers, celery or onions. Some folks like to can tomatoes in a pressure canner because it takes much less time and uses less fuel/energy.

4) If using a pressure canner with a dial gauge, have it checked annually to make sure it is reading properly. Check with the manufacturer regarding gauge testing or call the Home and Garden Education Center.

5) If you are pressure canning, be sure that the gasket is still soft and pliable. If dry and/or cracked, you need to replace it.

6) Use high quality, just-ripe produce for canning. You will never end up with canned tomatoes (or any other produce) better than those you started with. Overripe strawberries can lead to a runny jam. Overripe, mushy or decayed tomatoes (often sold in baskets labeled “canning tomatoes” when they are really “tomatoes that we can’t sell for slicing because they are past their prime”) may have a lower acid level or higher pH, making the processing time inadequate for safety.

7) Make sure everything is clean before your start. Be sure to clean:
 Canners (often stored in a cobwebby corner of the basement)
 Jars, jar lifter, screw bands, etc.
 Counter tops or other work surfaces
 Your produce (wash with cold running water—no soap or bleach please)
 YOUR HANDS

8) Follow approved recipes to the letter. When you change the amount or type of ingredient, you risk upsetting the balance that would result in a safe, high quality product. Too little sugar will make jams too soft; cutting out the salt may make a pickle recipe unsafe; and throwing additional onions and peppers into a tomato sauce can increase the risk for botulism.

9) Adhere to processing times—even if they seem long. Processing canned foods in a water bath or pressure canner is what makes these products safe for on-the-shelf storage. Each product is assigned the processing time needed to destroy the spoilage organisms and/or pathogens (the kind of bugs that make us sick) that are most likely to be a problem in THAT product.
 The short processing times for jams and jellies destroy yeasts and mold spores that used to be common place when these products were not water-bathed, but covered in paraffin.
 The long processing times for tomatoes are needed because modern tomato varieties are often lower in acid than those in the past. If 45 minutes seems way to long to you (especially when you watch the electric meter ticking away), you might want to consider pressure canning them for 15 minutes at 6 pounds of pressure or 10 minutes at 11 pounds.

10) Allow your jars to cool naturally, right side up, for 12 hours or more before testing seals. Testing earlier may cause the new seal to break.
 Cool jars away from an open window to prevent breakage by cool evening breezes on hot jars.
 Remove screw bands, clean and dry them and store several in a convenient place for use later when you open a jar and need to refrigerate leftovers. (Screw bands should not be left on jars when storing. Food residue and moisture may collect and cause rusting or molding that can ruin a good seal.)
 Test seals, reprocess if needed.

Follow the rules and you will be well on your way to processing a safe, shelf-stable food supply for your household.

For more information about canning food safely at home, visit our website at www.foodsafety.uconn.edu, check out the National Center for Home Food Preservation, or contact the Home and Garden Education Center at ladybug@uconn.edu or 1-877-486-6271.

So, You Want to Preserve Your Famous Salsa…

By Diane Wright Hirsch, MPH, RD

Extension Educator/Food Safety

canning tomatoesEvery year, about this time, I am spending time on the phone, talking people out of canning. Well, not exactly. I strongly encourage canning as a way to preserve summer tomatoes, peaches, apples and cucumbers (often as pickles). But, invariably I will answer the phone and on the other end of the line is someone who wants to can their FAMOUS salsa recipe (or pickles, or pesto, or peppers in oil). While I could write volumes on “What Not to Can”, salsa is the subject of this article.

The word “salsa” is the Spanish word for sauce. The Encyclopedia of American Food & Drink reports that the first mention of the term “salsa” appeared in print in the U.S. in 1962. As of 1991, they said, sales of salsa surpassed ketchup.

The origins of these sauces may be Aztec, when the traditional ingredients included tomatoes and chili peppers. But the creative cook can easily find recipes using a variety of ingredients such as beans, mangos, pineapple, grilled corn, avocado, or peaches. Historically, “salsa” was considered an uncooked sauce (salsa fresco or salsa cruda). But, in the interest of convenience, salsa is now most often processed in glass jars and found on the supermarket shelf next to taco shells, tortillas and refried beans (or in plastic tubs in the produce section).

Making and canning salsa in a commercial processing operation is one thing. Doing it at home is another.

Most salsa recipes are a mixture of low-acid foods (such as onions and peppers), with more acid foods (such as tomatoes). Often, there are additional acid ingredients that may include vinegar and citrus juices such as lemon, lime, or orange.

The types and amounts of ingredients used in salsa, as well as the preparation method, are important considerations in how a salsa is canned. Generally, acid foods (tomatoes, fruits) are safely canned in a boiling water bath canner. So folks may think that a tomato or fruit based salsa would also be safely canned in a water bath canner. However, once you add low-acid ingredients such as onions, peppers, black beans, corn, cilantro or avocado, the pH (measure of acidity) balance may be tipped to the low-acid side. At this point, the pH is likely at 4.6 or higher and the only safe way to can the product is in a pressure canner (to safely can in a water bath canner the product pH must be below 4.6).

If a salsa has enough low acid ingredients to render the final product, “low acid” by definition, then you run the risk of having a salsa that will support the production of deadly toxin by the Clostridium botulinum bacteria. Improperly canned salsas or other tomato-pepper combinations have been implicated in more than one outbreak of botulism poisoning. Follow these considerations for safe salsa:

Choose and use safe ingredients

The acid ingredients help preserve canned salsas and make them safe for water bath canning. Most often bottled vinegar or bottled lemon juice is used. Use only commercial and bottled products. An equal amount of bottled lemon juice may be substituted for vinegar in recipes, but do not substitute vinegar for lemon juice. This substitution will result in a less acid and potentially unsafe canned salsa. If the product is to “acidic” or tart for your taste, add a bit of sugar to offset. Do NOT cut down on the acid!

Tomatoes and/or fruit ingredients should be just ripe, free of cuts, rot, or mold. Do not reduce the quantity in the recipe. Overripe tomatoes may be too low in acid for safety. If green mangoes are called for in the recipe, do not use ripe mangos as they also may be too low in acid for safety.

Peppers, onions, and other low acid ingredients must also be added in amounts given in the recipe. An extra pepper might just throw you into the low acid realm…measure and count carefully.

Spices such as cumin, dried oregano, salt and pepper can be adjusted to taste. However, fresh herbs such as cilantro (a low acid ingredient) should be added according to the recipe. You can always add the fresh herbs just before serving for the freshest flavor.

Choose and use a safe recipe

The USDA/Extension mantra has always been, “Only use tested, science-based home-canning recipes from reliable sources like the National Center for Home Food Preservation and some equipment or home preserving ingredient manufacturers.” This is especially true for any acidified food like salsa or pickles. Then, follow the directions, ingredient list, and amounts listed in the recipe. Never add flour, cornstarch or other thickeners—this will have an effect on the processing time needed to heat the interior product to a safe temperature. Store opened salsa in the refrigerator once opened.

If you want to stick with a personal favorite recipe, there are two things you can do. Can a basic salsa and add additional ingredients (beans, corn, avocado) just before serving. Or, make your FAMOUS salsa and store it in the refrigerator for up to one week or freeze it for up to one year. Freezing will certainly affect the texture of your fresh salsa, so test out a small portion first to see if you like it.

For more information about making and preserving salsa, go to www.uga.edu/nchfp (National Center for Home Food Preservation). On that site you will find the fact sheet (some of the information in this article was from this fact sheet), Canning Your Own Salsa Recipe. Or contact the Home and Garden Education Center at ladybug@uconn.edu or 1-877-486-6271.

Getting Ready for Home Preservation Season

By Diane Wright Hirsch, MPH

Senior Extension Educator/Food Safety

As the end of June looms, back yard gardeners and farmers alike are beginning to see the fruits (and vegetables) of their labor. Already we are enjoying locally grown spinach, lettuces, herbs and other greens, peas, and perhaps locally grown broccoli and cabbage. Asparagus season is over, and strawberries, thanks to a later season, may be around for a few more weeks. But as we go through July, we can look forward to blueberries, summer raspberries, green beans, beets, cucumbers, peppers, and the holy grail of fresh sweet corn and field tomatoes. So far the growing season has been blessed with sufficient rain and good weather, crops are happy and will likely be very productive.

So, now is the time to begin preparations for safe home food preservation, whether you have a garden or a favorite farm or farmers’ market.

First, determine what method of home food preservation works best for you. Your choice may depend on your preference for the resulting product (frozen vs canned green beans, for example, are very different in taste and texture); your storage space; the tools or resources you have at your disposal (Canner? Pressure canner? Separate deep freezer? Refrigerator freezer only?); and, perhaps, the cost of the process. Since most folks think that preserving at home will save them money, a recent article from the University of Maine, The Cost of Preserving Food in Maine (https://extension.umaine.edu/publications/4032e/ ), might make a good read.

They looked only at the costs of energy (in Maine) and equipment used to preserve food as the cost of the food itself varies depending on where it is purchased. When freezing, the most expensive part of the equation is the freezer itself. After that, they factored in the cost of energy and the container, which in this case was a reusable container. One time use containers and freezer bags will add to costs. Freezing was estimated at 38 cents per pound of food.

The cost of pressure canning is $1.14 per pound, while using a water bath canner will cost approximately 73 cents per pound. The difference here is the cost of the canner. A pressure canner is over three times the cost of a water bath canning pot when amortized over 20 years. (Using these figures and assuming the cost of a pound of fresh tomatoes is $3.50, and 91% of the pound is useable, the cost of a pound of home canned tomatoes is approximately $3.92. The cost of a pound of commercially canned tomatoes is about 92 cents.*)

Finally, dehydration is a rather costly operation in this part of the world at 99 cents per pound. You must use an electric dehydrator to be successful as the climate (some heat, more humidity) will not allow us to use the sun alone.

The differences may not seem significant unless you are putting away large quantities of food. I had always thought that freezing was the most expensive option. Not according to this study. The efficiency of modern freezers has probably changed this.

Once you decide which method you will use, then start gathering your supplies. As someone who likes to procrastinate, local sources can get depleted over the course of the summer season. Online sources are more reliable as it gets closer to September.

If freezing:

  • If you need to purchase a freezer, keep in mind that a full freezer is more efficient. Buy only the space you need, do not overbuy. An upright is less efficient than a chest freezer, but I find it very easy to lose things in a deep chest freezer!
  • If you own a freezer, eat what you can out of your freezer to make room for the new crop.
  • Stock up on containers. Reusable are best. Make sure they are appropriate for the freezer. Some plastics will crack when frozen. Rigid containers stack more easily. If using freezer bags, again, make sure they are freezer and not simply food storage bags.
  • A permanent marker and freezer tape or labels are essential as well.

If canning:

  • Purchase a new or check the condition of your water bath canner. The water bath canner or large pot should be clean, have a lid, and a rack to hold the jars off the bottom. Be sure you can locate all the pieces and replace what might be missing.
  • Purchase a new pressure canner or, if you already own one, keep in mind that a pressure canner with a dial gauge needs to be tested yearly. Have that done now. We do pressure gauge testing here at the office (hirsch@uconn.edu) or call 203.407.3163. If you cannot make it here, you can send gauges to your canner manufacturer to be tested. That will take some time, so get it done as soon as possible. Be sure to check your gasket and other rubber parts to make sure they are not dried out or cracked. If they are, replace them. Make sure there is a rack to keep jars off the bottom of the canner.
  • Check your supply of jars, lids and rings. The sealing compounds on lids can dry up and crack. Check the date on the box. If older than two or three years, it would be best to buy new. If jar rings are rusty, you should replace them. Check your jars. If the rims are chipped or cracked, replace with new. A chipped rim will prevent a good seal from forming.
  • Find or replace your other tools: timers, spatulas, jar lifters, ladles, funnels, etc.

If dehydrating:

  • Purchase or check on your dehydrator to make sure that it is working and that you have sufficient racks or screens.
  • Purchase your storage equipment, whether it is freezer bags, canning jars or other air tight, food-safe containers.

Of course, when you get ready to can, freeze or dehydrate, be sure to make sure all of your equipment is cleaned with detergent and hot water prior to using. Follow instructions for preparing canning jars and lids.

Last, but not least, update your information regarding safe home food preservation. Check with the National Center for Home Food Preservation http://nchfp.uga.edu/. In addition to safe processing methods, they also have a blog that provides timely information and advice: https://preservingfoodathome.com/. The Ball Blue Book, generally recognized by Extension food safety professionals as safe, is updated regularly.

*Based on figures from USDA/ERS Fruit and Vegetable Prices, 2015

For more information on home food preservation, go to foodsafety.uconn.edu or contact the Home and Garden Education Center at ladybug@uconn.edu or 1-877-486-6271.

UConn Students Learn About Canning

Pressure cooker workshop Pressure cooker2

UConn Extension‘s Diane Hirsch held a workshop for 12 students from the UConn Spring Valley Farm and the UConn EcoGarden Club as well as others. The focus was on pressure canning as the Spring Valley Farm students hope to purchase a pressure canner in the near future. Julia Cartabiano, the farm manager, made the arrangements so that we could use the kitchen at the Whitney Dining Hall. We canned applesauce that the students had made.