General Canning Information

Answers to Common Questions About Home Canning, Freezing and Making Jams!

Home canning is both an art and a science. Safety and quality are some of the reasons it is important to follow recommended recipes and procedures for home canning. That is the science. The art comes from the experience of what is "finger tight", when is the product packed too full or too loose or determining just the right ripeness.
Following modern recommendations (which have improved a LOT in the past 25 years) will result in a wholesome, safe product 98% of the time. Sometimes even when you follow recommended, lab-tested, up-to-date directions, something goes wrong. A jar doesn't seal, liquid is lost out of the jar, and the fruit is floating! So what went wrong?
Here are questions and answers to trouble-shoot common canning issues.

General - Canning Process

What about other canning methods (oven, microwave, steam, adding aspirin, etc.)
This answer is from the National Center for Home Preservation:
"Open-kettle canning and the processing of freshly filled jars in conventional ovens, microwave ovens, and dishwashers are not recommended, because these practices do not prevent all risks of spoilage. Can I blanch in my microwave oven?
Microwave blanching may not be effective, since research has shown that some enzymes may not be inactivated. Steam canners are not recommended because processing times for use with current models have not been adequately researched. Because steam canners do not heat foods in the same manner as boiling-water canners, their use with boiling-water process times may result in spoilage. It is not recommended that pressure processes in excess of 15 PSI be applied when using new pressure canning equipment. So-called canning powders (like salicylic acid, aspirin) are useless as preservatives and do not replace the need for proper heat processing. Jars with wire bails and glass caps make attractive antiques or storage containers for dry food ingredients but are not recommended for use in canning. One-piece zinc porcelain-lined caps are also no longer recommended. Both glass and zinc caps use flat rubber rings for sealing jars, but too often fail to seal properly.
If my recipe doesn't call for processing, do I need to do so?
Yes. Canning recipes prior to 1990 should not be used. Many old recipes do not include instructions for processing foods. The foods are canned by the open kettle method, sealed and stored. This method for canning, the open kettle method, is not recommended for it presents a serious food safety hazard. All high acid foods should be processed in a water bath canner and all low acid foods in a pressure canner.
I was with my girlfriend canning today. It was my first time but she does it all the time. After reading your website it says to boil the jars after they are filled ad sealed for sterilization. We did not do this. Is this something that has to be done every time? And if so what will happen if we don't?
Yes, that is a very important step. That's how the bacteria get destroyed. Otherwise, some botulism spores are still alive inside, thanks to airborne contamination. Over time, they will grow and spoil the food and/or result in food poisoning.
It won't necessarily happen every time; maybe the food is acid enough, or the level of airborne or surface contamination was low enough that it won't be noticeable, but it's like play Russian roulette.
If you promptly refrigerate the jars you just canned, and use them as if they need to be refrigerated, you should be fine! But next time, process them through a boiling water bath!
Why is can't I just pack the hot food into jars, seal, and invert them? Why is this "open kettle canning" not recommended?
In open kettle canning, food is cooked in an ordinary kettle, then packed into hot jars and sealed without processing. The temperatures obtained in open kettle canning are not high enough to destroy all spoilage and food poisoning organisms that may be in the food. Also, microorganisms can enter the food when it is transferred from the kettle to jar and cause spoilage.
"Can food be re-canned if the lid does not seal?
Canned food can safely be recanned if the unsealed jar is discovered within 24 hours. To re-can, remove the lid and check the jar sealing surface for tiny nicks. Change the jar; if necessary, add a new treated lid and reprocess using the same processing time.
If canned foods have been frozen during storage, are they safe to eat?
Freezing does not cause food spoilage unless the seal is damaged or the jar is broken. These often happen as the food expands during freezing. Frozen foods, however, may be less palatable than properly stored canned food. In an unheated storage place, protect canned foods by wrapping the jars in paper or covering them with a blanket.
If my recipe doesn't call for processing, do I need to do so?
Many recipes passed down through the years or found in older cookbooks do not include instructions for processing. The foods are usually canned by the open kettle method, sealed and stored. Foods prepared in this manner present a serious health risk — particularly low acid foods. To minimize the risk of food spoilage, all high acid foods should be processed in a water bath canner or pressure canner and all low acid foods in a pressure canner.
What do "hot pack" and "raw pack" mean? What is the difference between "Hot packing" and "Raw packing"
Raw-packing is the practice of filling jars tightly with freshly prepared, but unheated food. Hot-packing is the practice of heating freshly prepared food to boiling, simmering it 2 to 5 minutes, and promptly filling jars loosely with the boiled food. See this page for diagrams and much more information about it!
What is "headspace"?
The unfilled space above the food in a jar and below its lid is referred to as headspace. See this page for a detailed answer!
Do I really need to leave a certain amount of headspace in the jar?
Yes, leaving the specified amount of headspace in a jar is important to assure a vacuum seal. If too little headspace is allowed the food may expand and bubble out when air is being forced out from under the lid during processing. The bubbling food may leave a deposit on the rim of the jar or the seal of the lid and prevent the jar from sealing properly. If too much headspace is allowed, the food at the top is likely to discolor. Also, the jar may not seal properly because there will not be enough processing time to drive all the air out of the jar.
How long will canned food keep?
Properly canned food stored in a cool, dry place will retain optimum eating quality for at least 1 year. Canned food stored in a warm place near hot pipes, a range, a furnace, or in indirect sunlight may lose some of its eating quality in a few weeks or months, depending on the temperature. Dampness may corrode cans or metal lids and cause leakage so the food will spoil. Jams will keep for a year, but are at their best if used within 6 months.
Is it necessary to sterilize jars before canning?
Jars do not need to be sterilized before canning if they will be filled with food and processed in a boiling water bath canner for 10 minutes or more or if they will be processed in a pressure canner. Jars that will be processed in a boiling water bath canner for less than 10 minutes, once filled, need to be sterilized first by boiling them in hot water for 10 minutes before they're filled. This means you ought to sterilize jars when making jams and jellies, since they only need to be processed for 5 or 10 minutes, whereas for applesauce, apple butter, etc., you needn't sterilize the jars (since these have processing times of 15 minutes or more). But in any case, common sense says run them through the dishwasher right before canning, and that will sterilize them anyway, so it is rather a moot point.
Is it safe to process food in the oven?
No. This can be dangerous because the temperature will vary according to the accuracy of oven regulators and circulation of heat. Dry heat is very slow in penetrating into jars of food. Also, jars explode easily in the oven.
Can two layers of jars be processed in a canner at one time?
Yes, two layers can be processed at one time, in either the boiling water bath or pressure canner. Place a small wire rack between the layers so water or steam will circulate around each jar. Make certain that the water covers the tops of all jars by 1 inch in a boiling water bath canner. The pressure canner should have 2 to 3 inches of water in the bottom.
Should liquid lost from the jar during processing be replaced?
No. Loss of liquid does not cause food to spoil, though the food above the liquid may darken. If, however, the loss is excessive (for example, if at least half of the liquid is lost), refrigerate the jar(s) and use within 2 to 3 days.
Why did my jars lose some much liquid? The liquid level in some of the jars went down by half!
Sometimes after processing, some of the liquid in the jar is lost and doesn't cover the product. Some causes are:
  • Packing food too tightly or loosely in the jar.
  • Starchy foods, such as corn, peas or lima beans, absorbed all the liquid. Use more liquid with these starchy vegetables.
  • All bubbles were not removed from the jar before capping.
  • Jars filled too full.
  • Fluctuating pressure in the pressure canner. Let pressure return to zero gradually, avoiding the sudden release of pressure through the vent. Do not hasten the cooling with cold water.
  • Jars are not totally covered with boiling water during the boiling water bath processing.
Pressure Canning

Is it necessary to exhaust a pressure canner?
Yes, it is very important to allow steam to escape for 10 minutes before closing the valve, or placing the weight on the vent. If the canner is not exhausted, the inside temperature may not correspond to the pressure on the gauge.
Why is there sometimes a loss of liquid during processing?
Loss of liquid may be due to the fluctuating pressure in the pressure canner, food packed too tightly in jars or lowering pressure too suddenly. At the end of processing time, allow the pressure to drop to zero naturally and wait two to five minutes before opening the lid.
Am I able to process green beans in a hot water bath? A lady at the farm market here told me she has always done it this way, boiling it for 3 hours. I just wanted to be sure this is a safe method before doing it.
Nope. That lady is, well, nuts! It doesn't matter if you boil them until they turn to mush, because boiling water at sea level never gets any hotter than 212 F, and the Clostridium botulinum is not killed by 212 f; even for hours. It's just enjoying a nice bath.
A water bath canner is fine for acidic fruits and vegetables, such as jams, jellies, applesauce, apple butter, and even tomatoes, but for almost all other vegetables, like carrots, squash, green beans, etc. you'll need a pressure canner.
Quoting from the Ohio State University Extension's Fact Sheet:
"Pressure canning is the only safe method for home canning vegetables. Clostridium botulinum is the bacterium that causes botulism food poisoning in low-acid foods, such as vegetables. The bacterial spores are destroyed only when the vegetables are processed in a pressure canner at 240 degrees Fahrenheit (F) for the correct amount of time.
The spores are present everywhere, but are harmless until it finds itself in a moist, low-acid, oxygen-free environment or a partial vacuum. Under these conditions, the bacterium can grow and produce toxins dangerous to people and animals.
Only subjecting it to the higher temperatures (240 F) of a pressure canner can the spores be killed.
So how did the lady survive? She probably just ate her goods before enough of it grew to reach toxic levels.
But that doesn't make it smart. We all know people who smoked a pack a day and lived to 90. But that doesn't make it smart nor safe to do.

I don't have enough berries to make jam yet. Can I freeze them as they come in from my garden and then make jam from them when I have enough?
Definitely! I do it all the time. This works for berries (blueberries, raspberries, blackberries, strawberries, etc.) and many other fruit (like peaches, figs). And if they will only be in the freezer for a month or two before using them to make jam or other cooked products, there is no need to blanch them. It does help to prepare them a bit - like removing the hulls from strawberries, etc.
Jars, Lids and Containers

As my jars are cooling after I take them out of the canner, they sometimes make a popping or hissing noise. Is this normal and safe?
Yes, the lids are designed to flex and that's actually a key selling point. You can tell if a jar hasn't sealed properly (after it has cooled completely) if the lid flexes and makes a popping sound when you press the center of the lid with your finger. The popping sounds while it is cooling is the lid being sucked down by the vacuum that is forming inside the jar - which a normal part of the sealing process. Hissing sounds are usually just escaping steam or hot water evaporating on hot surfaces, also normal!
Can I use empty mayonnaise and spaghetti jars that have threads to use the same size rings and lids as Ball jars?
Most commercial pint- and quart-size mayonnaise or salad dressing jars can be used with two-piece rings/lids for canning acid foods in a water bath canner. I've used them for decades, myself. However, you should expect slightly more seal failures and jar breakage. These jars have a narrower sealing surface, are tempered less than Mason jars, and may be weakened by repeated contact with metal spoons or knives used in dispensing mayonnaise or salad dressing. Seemingly insignificant scratches in glass may cause cracking and breakage while processing jars in a canner. Mayonnaise-type jars are definitely not recommended for use with foods to be processed in a pressure canner because of excessive jar breakage. Other commercial jars with mouths that cannot be sealed with two-piece canning lids are not recommended for use in canning food at home.
How would you go about using different jars for canning sauce ? In other words, not using mason jars but other jars with screw on lids? Would you go about it the same way or is there a different way? My concern would be the lids and having them sealing properly.
Well, the "authorities" all say NEVER use anything but Ball / Kerr and other canning jars. In practice, many home canners find (through practice) that certain products (like Classico brand spaghetti sauce) are packaged in jars that are the same specification as commercial home canning jars.
And that's about it- it the lid and ring fits and the lid seals, the only other concern is whether the glass is thick enough to withstand the usual home canner banging it around. I've had a few "Miracle Whip" jars break, so I don't use those anymore, but the Classico's work fine for me. Note that the Classico's manufacturer does not recommend reuse of their jars.
"Can I reuse the Classico® jar for home canning?
No. A coating is applied at the glass plant to reduce scratching and scuffing. If scratched, the jar becomes weaker at this point and can more easily break. This would increase the risk of the jar breaking when used for canning. Also, the lighter weight of our current jar could make it unsafe for home canning. "
Is it all right to reuse jar fittings (lids and bands)?
Lids should not be used a second time since the sealing compound becomes indented by the first use, preventing another airtight seal. Screw bands may be reused unless they are badly rusted or the top edge is pried up which would prevent a proper seal.
A neighbor generously gave me 2 boxes of canning jars that are the old fashioned glass top with a wire on the top (lightening jars perhaps?) There isn't any rubber gasket on these and I wondered if I should try to find them in the store or if the jars should be reserved for non-canning uses, like dry food storage or decoration. Do you recommend using these old jars or should I keep to my typical top and ring jars
Stick to the lid and ring types. The others leak and spoil a lot. They're not really safe for vegetables. The type with the glass lid with a gas and a wire to hold it down works ok for jam, since jam doesn't spoil as readily and is high in acid. But, really, they're only for decoration these days. The Ball/Kerr/Mason ring and lid types are SO much more reliable and safer.
Why do the undersides of metal lids sometimes discolor?
Natural compounds in some foods, particularly acids, corrode metal and make a dark deposit on the underside of jar lids. This deposit on lids of sealed, properly processed canned foods is harmless.
What causes jars to break in a canner?
Breakage can occur for several reasons: 1. Using commercial food jars rather than jars manufactured for home canning, 2. Using jars that have hairline cracks, 3. Putting jars directly on bottom of canner instead of on a rack, 4. Putting hot food in cold jars, or 5. Putting jars of raw or unheated food directly into boiling water in the canner, rather than into hot water (sudden change in temperature-too wide a margin between temperature of filled jars and water in canner before processing).
How can I remove scale or hard-water film from canning jars?
Soak jars for several hours in a solution containing 1 cup of vinegar and 1 gallon of water.
What can I process in half-gallon canning jars?
One or more canning jar manufacturers are selling half-gallon canning jars. One manufacturer has a printed note on the top that says half-gallon jars are only used for some highly acidic foods in a boiling water canner.
The only processes that USDA, the National Center for Home Food Preservation and the University of Georgia have to recommend for half-gallon jars are for very acidic fruit juices (and juice only): See more information on their web site here: Apple Juice ( and Grape Juice ( This process time is not to be used for tomato juice, for example.
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.
We are aware that there are historical recommendations for canning foods in half-gallon jars. However, these are not currently accepted or endorsed by the USDA, Cooperative Extension System or U.S. manufacturers of home canning jars.

Some of my jars failed to seal. What can I do to prevent jars not sealing?
To avoid having a jar fail to seal after processing:
  • Use only standard canning jars. The glass in commercial jars (such as pickle or mayonnaise jars) doesn't have adequate lip thickness and thread depth needed for a good seal.
  • Use a two-piece lid (flat and screwband). Do not use a one-piece lid as a substitute for a screwband. The ring may be re-used if it is not bent or rusty. Use a flat lid only once. Even mixing brands of flats and rings can cause sealing problems because of the design. Brand names are now stamped on the rings.
  • Be sure the lip of jar is clean and not chipped.
  • Follow headspace directions to avoid having liquid boil out of jars (siphoning) during processing. Headspace is the space between the inside of the lid and the top of the food. During siphoning, food particles in liquid may interfere with a seal. The ring (screw band) should be "finger tight" (tightened by hand) - not too tight or too loose. The band and lid are designed to let air vent from the jar during processing.
  • Use jar lifter to remove each jar after processing so that the lid is not disturbed. Sealing takes place AFTER the jar is removed and starts to cool. Do NOT turn jars upside down.
  • Be sure the correct processing time is used for the product being canned.
How can I tell if something I've canned has gone bad (spoiled, gone off)?
That is one of the challenges of any canned food, even store bought.
Generally speaking, spoilage is indicated by:
  1. the lid is bulged or flexes (isn't sucked down tight), then gas has built up from decay.
  2. Any signs of seepage or leaks (they should be fairly clean come out of the water bath).
  3. Finally, an off smell, visual signs of mold, or a change in color or texture from what it should be!
If I find mold growing inside a jar of canned food, can I just scrape it off and eat the food?
Mold growth in foods can raise the pH of the food. In home canned products, this could mean that the high acid products could become low acid and therefore run the risk of botulism or other bacterial spoilage. Thus, any home canned product that shows signs of mold growth should be discarded. The exception to this is jellied products. (where sugar is added). In these the high sugar content would prevent the growth of Clostridium botulinum. In jellied products, remove any surface mold plus 1/2 inch of the good product underneath and then use the rest immediately. Jellied products with extensive mold should be discarded.
I made peaches but immediately after I pulled them out of the water I knocked two jars over and they are now hissing at me I'm not too impressed either! Do these need to be eaten right away now? What happens when you bump them?
Depends! You may just have disturbed them and leak a bit and then they resealed themselves. Or they're still leaking. So when they cool, check for a good seal and vacuum: is the lid still sucked down, and doesn't flex or pop when you press in the middle? Do any liquids leak out when you turn the jar upside down? If not, they're probably fine. But I'd mark them to be eaten first!
How to do test my jars for a good seal? How can I tell if they've sealed properly?

After cooling jars for 12 to 24 hours (until they are room temperature), remove the screw bands (rings) and test the seals by one of the following options:
Test 1: Press the middle of the lid with a finger or thumb. If the lid springs up when you release your finger, the lid is unsealed.
Test 2: Hold the jar at eye level and look across the lid. The lid should be concave (curved down slightly in the center). That is due to the vacuum sucking the center of the lid down. If center of the lid is either flat or bulging, it may not be sealed.
Test 3: If liquids leak out when you turn the jars on their sides or upside down, it definitely is not sealed!
Some of my pressure-canned jars spoiled. What can I do to prevent spoilage when I use the pressure canner?
To avoid spoilage:
  • Use the correct processing pressure and time adjusted for altitudes above 1,000 ft (if you are)
  • Remove jars immediately from the pressure canner when processing time is up and pressure returns to zero. In other words, don't try to hasten the the process after the processing time is up but putting the canner under running water
Cloudy liquid SOMETIMES denotes spoilage but could be caused by starch from vegetables like peas, corn or lima beans, minerals in the water, or using table salt with fillers. Cloudiness is not necessarily harmful, but the product probably wouldn't win a prize at the county fair!
Some of my water-bath-canned jars spoiled. What can I do to prevent spoilage when I use the water bath canner?
To avoid spoilage:
  • Use the correct processing time adjusted for altitudes above 1,000 ft (if you are)
  • In the boiling water bath, water should boil continuously during the processing time with the water level covering the jars by at least one inch.
Ingredients and Additives

Is it safe to can food without salt?
Yes. Salt is used for flavor and is not necessary to prevent spoilage.
Is it safe to can fruits without sugar?
Yes. Sugar is added to improve flavor, help stabilize color, and retain the shape of the fruit. It is not added as a preservative.
Can fruits and vegetables be canned without heating if aspirin is used?
No. Aspirin should not be used in canning. It cannot be relied on to prevent spoilage or to give satisfactory products. Adequate heat treatment is the only safe procedure.
Is it safe to can green beans in a boiling water bath if vinegar is used?
No. Recommended processing methods must be used to assure safety. Recommended processing times cannot be shortened if vinegar is used in canning fresh vegetables (this does not refer to pickled vegetables).

Should all vegetables be precooked before canning?
For best quality, yes. However, some vegetables can be packed raw or cold into jars before being processed in the pressure canner.
What vegetables expand instead of shrink during processing?
Corn, peas and lima beans are starchy and expand during processing. They should be packed loosely.
What causes corn to turn brown during processing?
This occurs most often when too high a temperature is used causing caramelization of the sugar in the corn. It may also be caused by some minerals in the water used in canning.
Why is canning summer squash or zucchini not recommended?
Recommendations for canning summer squashes, including zucchini, that appeared in former editions of So Easy to Preserve have been withdrawn due to uncertainty about the determination of processing times. Squashes are low-acid vegetables and require pressure canning for a known period of time that will destroy the bacteria that cause botulism. Documentation for the previous processing times cannot be found, and reports that are available do not support the old process. Slices or cubes of cooked summer squash will get quite soft and pack tightly into the jars. The amount of squash filled into a jar will affect the heating pattern in that jar. It is best to freeze or pickle summer squashes, but they may also be dried.
How about home canning of garlic?
Sorry! Home canning of garlic is definitely not recommended - it is a very low acid food so it is perfect for growing botulism. It also loses a lot of the flavor. It can be canned commercially because of the special high temp/high pressure equipment they have.
See this page at UC Davis for additional information.
Is there a way to can cabbage without making kraut or pickled cabbage?
Nope. Here's what the University of Missouri Food Sciences dept says:
"Canned cabbage is a very poor quality product. For this reason, we do not have any scientifically researched times for canning cabbage. There are several other alternatives: Cabbage, including Chinese cabbage, can be frozen, using directions in GH 1503, "Freezing Vegetables." Or, cabbage can be made into "freezer coleslaw." Directions are in issue 83-7 of the "Grapevine" newsletter. Barbara Willenberg, Nutritional Sciences, University of Missouri-Columbia. "
Can I can my own salsa recipe?
Salsas are usually mixtures of acid and low-acid ingredients; they are an example of an acidified food. The specific recipe, and sometimes preparation method, will determine if a salsa can be processed in a boiling water canner or a pressure canner. A process must be scientifically determined for each recipe. To can salsa at home, use our recipes for Hot Chile Salsa or Mexican Tomato Sauce. Your County Extension agent may have additional tested recipes for salsas.
What is blanching?
Heating or scalding vegetables in boiling water or steam for a short period of time.
Is it recommended to blanch vegetable before freezing?
YES. Blanching slows or stops the action of enzymes which cause loss of flavor, color and texture. Blanching cleanses the surface of dirt and organisms, brightens the color and helps retard loss of vitamins. Blanching also wilts or softens vegetable and makes them easier to pack.
Why is it necessary to cool vegetables after blanching?
Vegetables should be cooked quickly and thoroughly after blanching to stop the cooking process. Otherwise, vegetables will be overcooked with loss of flavor, color, vitamins and minerals.
You mention to begin counting the blanching time as soon as you drop the vegetables to be blanched into the boiling water....instructions I have read on other sites say to begin counting the blanch time after the water returns to a boil. Which is right? I don\'t want my veggies undercooked as I need to destroy the enzymes and bacteria, but I don\'t want them overcooked either so they are like mush when I get them out of the freezer..
Well, the difference between the two methods is small; and the larger the pot of water is, the smaller the difference, so it shouldn't have much effect either way. I tend to go for slightly shorter times on veggies that ought to be crisp (like cucumbers or corn) because there is a greater likelihood that overcooking will turn them to mush more than enzymatic action. Many folks skip the blanching step entirely, if they have a deep freeze and will only be store up to 5 months.
How do I can oil with herbs? Can I can pesto?
Herbs and oils are both low-acid and together could support the growth of the disease-causing Clostridium botulinum bacteria. Oils may be flavored with herbs if they are made up for fresh use, stored in the refrigerator and used within 2 to 3 days. There are no canning recommendations. Fresh herbs must be washed well and dried completely before storing in the oil. The very best sanitation and personal hygiene practices must be used. Pesto is an uncooked seasoning mixture of herbs, usually including fresh basil, and some oil. It may be frozen for long term storage; there are no home canning recommendations.
Squash and Pumpkins

How do I preserve pumpkin or winter squashes, like butternut squash? Do you recommend canning or freezing and what is the proper method?
I usually just store it in a cool dark place (basement). It will keep for many months (I've had some last 8 months). Just lay them out on newspapers with a couple of inches between each squash.
You can also cook it and freeze the pulp.
You can "can" it, but it has very low acid, so it requires a pressure canner, and you only cube the pulp, not mash it. It's a bit tricky. I'll put together a set of directions on it shortly!
What about canning summer squash or zucchini?
The USDA and the major universities with food science departments, like UGa, Clemson do not recommend canning summer squashes, including zucchini and yellow squash because squashes are low-acid vegetables and require pressure canning for a known period of time that will destroy the bacteria that cause botulism. Documentation for the previous processing times cannot be found, and reports that are available do not support the old process. Slices or cubes of cooked summer squash will get quite soft and pack tightly into the jars. The amount of squash filled into a jar will affect the heating pattern in that jar. The bottom lines is there just are no tested recipes for it. If you do using a hand-me-down recipe, you may have no problems... or you may get botulism, which can kill you. It is best to freeze or pickle summer squashes, but they may also be dried.
Pickles and Pickling

Pickles seem to have their own unique problems in canning. Poorly home-canned pickles may be soft or slippery, shriveled, hollow, too dark, have black spots, be faded, have a bitter flavor or develop white sediment at the bottom of the jar.
Some factors that affect pickle quality:
  • Growing conditions of the cucumbers.
  • Time of day picked.
  • How the cukes were stored (refrigerator) after picking and how long before pickling.
  • Too high processing temperature or processing omitted.
  • Brine too weak (for those recipes that use brine).
  • Vinegar solution too dilute or too strong.
  • Hard water.
Can I use flaked salt for pickling?
Most recipes call for granulated pickling salt or canning salt. Flake salt varies in density and is not recommended for pickling,
I don't have the type of dill my recipe calls for. How can I substitute what I have?
For each quart try 3 heads of fresh dill or one tablespoon dill seed.
Can I use burpless cucumbers for pickling?
Yes, smaller burpless cucumbers (those with small seeds) are used, they may be suitable for making all sorts of fresh pack and quick process pickles, including dills. The skins on burpless cucumbers may be tougher, though.
On the other hand, according to the UGA food science dept, burpless cucumbers are not recommended for use in fermented pickle recipes because at maturity, they produce a softening enzyme that causes the pickles to soften during fermentation.
Why did the garlic cloves in my pickles turn green or bluish green?
This reaction may be due to iron, tin or aluminum in your cooking pot, water or water pipes reacting with the pigments in the garlic. Or, the garlic may naturally have more bluish pigment and it is more evident after pickling . The pickles are safe to eat.
Why are my pickles soft?
Any of the following may cause soft pickles: failure to remove the blossom end of the cucumber, cucumbers are exposed above the brine, vinegar or brine is too weak, or pickles were precooked at too high temperature (overcooked).
After I can my pickles, if a jar does NOT seal, is it still good? Can I still eat the pickles?
As long as you refrigerate the jar soon after it cools to room temperature, yes. Of course, since it isn't sealed, it won't last forever even in the fridge, so just treat it as you would any other fresh food.

Why do foods darken in the top of jars?
  • Some air was left in the jar (bubbles not released adequately).
  • Not enough liquid in jar.
  • Loss of liquid from siphoning.
  • Food not processed long enough to destroy enzymes.
Liquid did not cover the food or the food was not processed long enough to destroy enzymes. The food is safe to eat. However, you can scoop it off and discard the darkened top layer if you like.
What causes fruit, like peaches, to float in jar?
There are a variety of reasons why fruit floats:
  • Overripe fruit - the acid and pectin content is lower. Pectin helps hold fruit in suspension.
  • Over-processing destroys some of the pectin.
  • too much sugar (it's the density or fruit v. solution, fruit is lighter than the syrup ) - Using a heavy syrup (a medium or light syrup is recommended).
  • Packing fruit too loosely in the jar. If jars are packed too loosely or if air remains in the tissues of the fruit after processing. Pack the fruit tightly in jars without crushing it.
It can also be due to the canning method - raw v. hot packing. Raw-packing is the practice of filling jars tightly with freshly prepared, but unheated food. Such foods, especially fruit, will float in the jars. The entrapped air in and around the food may cause floating and discoloration within 2 to 3 months of storage. Raw-packing is more suitable for vegetables processed in a pressure canner. Hot-packing is the practice of heating freshly prepared food to boiling, simmering it 2 to 5 minutes, and promptly filling jars loosely with the boiled food. Whether food has been hot-packed or raw-packed, the juice, syrup, or water to be added to the foods should also be heated to boiling before adding it to the jars. This practice helps to remove air from food tissues, shrinks food, helps keep the food from floating in the jars, increases vacuum in sealed jars, and improves shelf life. Preshrinking food permits filling more food into each jar. Hot-packing is the best way to remove air and is the preferred pack style for foods processed in a boiling-water canner. At first, the color of hot-packed foods may appear no better than that of raw-packed foods, but within a short storage period, both color and flavor of hot-packed foods will be superior.
When I put the jars into the water to be processed, air bubbles were coming out from the lids... is that normal?
Yes, that's due to the expansion of the contents of the jars are they heat in the water bath - the liquids expand and press out some air - that's what creates the vacuum when the jars cool and causes the lids to adhere tightly - so it's really a good thing!
Is a way to can strawberries whole instead of freezing them?
Yes, you can "can" (bottle or tin, if you prefer)! I tested a recipe and published the directions with photos on this page: how to can blueberries, raspberries, blackberries, currants, dewberries, elderberries, gooseberries, huckleberries, tayberries, loganberries and mulberries.!
Plums: Please let me know what you think of the "keep the skin on" and "keep the pits in when you boil" folks. I'm inclined to remove the skin (but not certain). But the pits...seems they impart some positive aspect to the flavor if left when boiling?
It's really just personal preference. The skins will add some color and help hold the fruit together. The pits don't add anything of value to the flavor (they're actually bitter if you were to crunch one and taste it), so if they're freestone and you can remove the pits , I would... but that's just my preference!
Can I home can fully cooked Apple Cobbler, Peach Cobbler, Blackberry Cobbler, other fruit cobblers, etc.?
I'm sure under some circumstances, it can be done, certainly with commercial equipment. The problem is that the recipes have not been tested for safety in university, USDA or FDA labs using home canning equipment. Because of the addition of low acid fillers (flours, starch, bread, etc.) we can't be sure that heat penetration will be uniform and botulism and other harmful bacteria will be destroyed.
A safer method would be to can the filling (apples or other fruit, sugar and spice) using the apple pie filling directions (with or without addition of the Clear-gel starch; you can always add the starch later) and simply add the flour, butter, starch and other ingredients and bake the cobble at the time you want to consume it!
Can I freeze oranges and other citrus?
The growers typically flash freeze and concentrate the juice, but not the fruit or pulp. Here's what one of the grower's says: "When whole fruit is frozen, the juice expands and bursts the cells inside. When the fruit thaws the pulp will be dry and the peel will be mushy. Whole citrus does not freeze with good results. However, you can squeeze, then freeze orange and grapefruit juice."
Jams and Jellies

Should jelly be boiled slowly or rapidly?
Jelly should be boiled rapidly since long, slow boiling destroys the pectin in the fruit juice.
Can I make a double batch of jelly?
NO. If a larger quantity of juice is used, it will be necessary to boil it longer thus causing loss of flavor, darkening of jelly, and toughening of jelly.
Why is my jam too runny?
The following can cause soft jam: overcooking, processing too long, too little pectin, incorrect proportions of sugar and juice, undercooking, insufficient acid, or making too large a batch at one time.
Could you tell me why my JAM is thicker then the store bought?
The natural pectin content of fresh fruit varies, so it is possible the the variety of fruit that you used has more natural pectin, making it thicker. But there's an easy answer - just add less pectin next time. You'll have to experiment to find how much pectin makes the consistency you like. Most people seem to like their jam thick, so you may to need to only use 3/4 of a pack of pectin per batch.
I made some raspberry jam about 3 weeks ago and I noticed about 6 of my jars did not set properly. They are very runny! With this amount of time that has gone by can I re-do the jars again?
Yes, you can remake the jam later. 3 weeks isn’t so long, so the quality shouldn't be diminished by much. - just see this page for directions:
Why is my jelly soft?
The following can cause soft jelly: overcooking the fruit to extract the juice, using too much water to extract the juice, incorrect proportions of sugar and juice, undercooking causing insufficient concentration, insufficient acid, or making too large a batch at one time.
Can I use frozen fruit to make jams?
Absolutely! I usually freeze a dozen quarts of strawberries after I go picking! I wash them, hull them and slice them in half, then freeze them in heavy-duty Ziploc freezer bags (squeezing as much of the air out as I can, or using a vacuum FoodSaver and the vacuum bags. That way I can use those strawberries together with fruits that I pick later in the season, like blackberries, raspberries and blueberries to make mixed berry jams. You can use the frozen (without added sugar) fruit just the same as fresh. Just defrost them right before you use them.
Can anyone tell me why my jelly sometimes has bubbles in it after it has cooled down?
Bubble are trapped air or water vapor. When the jam is boiling, the bubbles rising from the bottom of the pan and air mixing at the surface become mixed in the jam. If the viscosity of the jam is high enough, the bubbles cannot break free. The foam produced is the portion that has the highest viscosity - this is when we suggest to skim off the foam. Many people add 1 teaspoon of butter or margarine to the jam before they start to cook it. This helps prevent the bubbles from forming. Exactly why, I can't tell you (it's been too many years since my fluid mechanics class in chemical engineering) - it probably has to do with disruption the surface tension or hydrophilic bonding; but the point is, it seems to work. Another method is to allow the jam to sit undisturbed for about 5 minutes after you remove it from the heat, then skim off the foam and jar the remaining jam and process it in your boiling water bath.
Other Problems and troubleshooting jellied productsMeats

Should giblets of chicken be canned in the same jar with chicken?
No. Their flavor may permeate other pieces of chicken in the jar.
Is it safe to can meat and poultry without salt?
Yes. Salt is used for flavor only and is not necessary for safe processing.
Why is it necessary to remove as much fat from meats as possible before canning?
Any fat that gets on the rim of the canning jar can prevent an airtight seal. Excess fat in jars makes it easier for the fat to climb the sides of the jar and contaminate the seal.
Can I get directions for canning my Brunswick stew at home?
Recommendations for canning Brunswick stews at home have not been scientifically determined. These are low-acid mixtures which could support the growth of bacteria that cause botulism, so a process cannot be estimated or made up. It must be a tested process known to kill these bacteria in this product. In addition, the recipes for Brunswick stew vary and a process would have to be developed through scientific testing for each variation. No directions for this product are available at this time. It is best to freeze Brunswick stews.
Miscellaneous Questions

If canned foods have been frozen during storage, are they safe to eat?
The answer is, yes, they are safe, as long at the seal remained intact. The quality may suffer; freezing usually ruptures cell walls of plant matter, so canned beans would probably be more mushy, whereas applesauce would be relatively unaffected. However, the key is to ensure that the seal on the jar hadn't been broken. When water freezes, it expands, so if the jar froze completely, it is very likely to have pushed the lid out. Obviously, with Ball/Kerr lids, it is easy enough to test the seal by seeing if the lid flexes (clicks in and out) when the jar is completely thawed again.
Can you give me tips on canning baby food?
I have a 2 year old myself, so I just went through canning baby food last year. Basically, it's the same as regular canning, etc. you'll need to chop or puree - which you can do when you use it, or in some cases, beforehand. Applesauce, for example, is a perfect ready-made baby food. If you want to can low acid foods (like most vegetables, aside from tomatoes and pickles), you'll need a pressure canner.
A big advantage of home-canned and home-frozen baby foods is the absence of food additives, preservatives, pesticides and other chemicals.
Since fresh foods and unprocessed foods are almost always better (more nutritious) than anything process or even cooked, I use the following hierarchy:
1. grow my own fresh fruits and vegetables
2. pick my own fresh fruits and vegetables from local farms
3. store fruits and vegetables in a cool dark place like the basement or garage
4. freeze fruits and vegetables
5. can fruits and vegetables
6. store-bought fresh
7. store-bought frozen
8. store-bought canned or otherwise processed
You'll find that a number of vegetables you can grow can just be stored in a basement - like sweet potatoes, onions, potatoes, winter squash (butternut, Hubbard, acorn, etc.) They'll keep for months - up to a full year under the right conditions. That's better than freezing or canning.
Some vegetables, especially low acid vegetables (which is most acid from tomatoes and anything pickled) require a pressure canner (see this page for models) to ensure they are safe.
AAside from those tips, any of the canning recipes on the website will for just the same! My baby's favorites were the applesauce, apple butter, a touch of homemade jam in yogurt, spaghetti sauce, canned or frozen beets, corn, peas and carrots.
Can I can bread or cake in a jar?
These products are not recommended for canning; choose recipes that you can freeze. In fact, most of these products are not really "canned." The directions call for baking in the jar and then closing with a canning lid. Many recipes for quick breads and cakes are low-acid and have the potential for supporting the growth of a bacteria like Clostridium botulinum if it is present inside the closed jar. One university's research showed a high potential for problems. You will see these products made commercially; however, additives, preservatives and processing controls not available for home recipes are used. Canning jar manufacturers also don't endorse baking in their canning jars.
Can I can my own mayonnaise?
It's possible, but I sure wouldn't recommend it. I haven't found ONE, not ONE set of directions discussing how to home can mayonnaise, not from any reputable website (like the USDA or a university food science department), nor any canning book.
Given the ingredient's propensity to easily spoil and how eggs are usually contaminated with salmonella anyway, and the low acid content... I'd say it's a recipe for severe food poisoning. Stick to making it, then refrigerating it.