Common Canning Questions
Common Issues with Jars and Lids on Cans
Q. Why makes Jars used for canning break?
Canning jars may break due to different reasons. The type of damage on the jar surface can reveal why it broke. For example, cracks noticed around the base of the jar are commonly due to extreme thermal conditions. These cracks can also be noticed on the sides of the jar.
To avoid such a situation, it is best to prevent sudden changes in temperature, such as putting hot content in cold jars. Cracks on jars can also occur when you put a cold jar in a bowl of hot water. Instead, jars should be warmed up before you put in hot food, and the cooling process can happen naturally.
Broken jars due to internal pressure
A build-up of pressure in the sealed jar can also cause cracks on the surface. The pressure responsible for cracks is due to overfilled jars. There is no space to accommodate expansion when the jar is placed in a hot environment.
To avoid the build-up of internal pressure which can cause canning jars to break, it is important to maintain the standard for packing jars which allows enough room for expansion. If the jars must be heated, a consistent temperature should be maintained.
Under processing, it is also important to move jars only after the pressure falls to zero. The drop in pressure should be normal process without any manipulation; it is also advised that jars should not be placed under running water for cooling.
Broken jars can also be due to impact with a harder surface, or when they drop. This implies the need to handle canning jars with care.
Some tips to avoid causing cracks in jars include; avoid the use of metal utensils such as spatula to remove air bubbles or cleaning jars with coarse pads such as those made from steel wool. Also, it is a good idea to replace jars after ten years or less, to avoid depreciation and low efficiency caused by aging and frequent use.
A quick test to determine if a jar is broken is by placing the jar in the water at room temperature and boiling for about fifteen minutes. If the breaks it has been previously compromised.
Q. Is there a way to confirm if canned food has been properly sealed?
Yes, there are some ways to check if canning jars are sealed. First, the jar should be cooled for about 12 to 24 hours.
Next, you can use any of the following techniques to determine if a jar is properly sealed;
- Remove the screw cover, place your thumb at the middle of the seal and apply little pressure, the seal should remain depressed when you remove your thumb. However, if it returns to the normal state before you pressed in, the jar may not be properly sealed.
- Listen for a high pitched resonating sound when you tap the seal with the underside of a teaspoon. If you hear a dull thud instead, the seal has been compromised.
- Raise the jar to your eye level and look at the seal; you should notice a slightly concave depression. If the seal appears to be bulging upwards, it may have been compromised.
Q. Should screw bands be closed very tight after using jars?
Applying excessive force when tightening screwbands can compromise the flat. Instead, screwbands should be closed in a firm way that they can be easily opened with the hands.
Q. At what point should lids with screwbands be tightened on canning jars?
It is essential to tighten the screwbands before processing to avoid compromising the seal. The screwbands can be tightened just before the jars are placed in the hot pressure canner.
Q. Why do lids of canning jars buckle?
Internal pressure in canning jars can be identified as the main reason lids buckle. Rapid changes in thermal conditions can cause the internal pressure responsible for damaged lids. Jars with buckled lids are inappropriate for storing food. If it is noticed that a lid has buckled, the jar should be kept in a refrigerator to preserve the food. The content in such jars must be consumed within two days.
Q. Why do some lids fail to seal?
The following reasons may have prevented the lid of canned jars from properly sealing.
- The damaged rim on the jar
- Nonadherence to the specifications of the manufacturer when making the flats
- Failure to clean rim of jars to ensure there are no food particles on the rim before sealing.
- Allowing too much headspace in a canned jar, or subjecting it to rapid changes in pressure. This can result in food particles getting on the rim before the jar is sealed. Presence of air in the jar. This can happen when the headspace allowance is too much; the presence of air can hinder the sealing process. It is essential that air bubbles are completely removed before canning jars are sealed.
- Very tight screw bands can also cause improper sealing.
- Waiting until the jar is extracted from the canner before tightening the screwbands.
- Using flat lids more than once can lead to a failure in the sealing process.
- Lids with poor quality.
- Reusing jars that are inappropriate for home canning. For example, jars used to can mayonnaise, peanut butter or baby food may not seal properly when used for home canning.
Q. If it is discovered that the lid is improperly sealed or food has not been adequately processed, what can be done as a solution?
There are some processes that can be done to prevent food from spoiling if the issue is discovered less than 24 hours after the food was processed. Here are some solutions;
- Put the jar in a refrigerator to preserve the food; it should be consumed within two days.
- The headspace in the jar should be adjusted to 1 ½ inch, if you have put vegetables in the jar, then it should be drained, place the jar in a freezer.
- The jar’s rim may be damaged; you can determine this by removing the lid to view the sealing surface. If any sign of damage is observed, change the jar and reprocess the food following the standard procedure.
It is not advisable to retain food in a damaged jar if the issue is noticed 24hours after processing. The food should be discarded.
Q. Is it possible to reuse lids and screwbands?
Yes is it possible, but you need to confirm the screwbands are in good condition. However, flat metal lids may not be reused.
Q. When is the right time to sterilize jars?
All jars should be sterilized shortly before they are used for canning. Sterilization is done by placing the jars in a hot water bath canner, fill the jars with hot water (close to boiling point), the water should cover the jars at a one-inch mark above the jar tip. Boil for ten minutes and drain the jars.
It is, however, not necessary to sterilize jars you want to use for vegetables, meats, fruits or tomatoes. This is because these jars will be processed for ten minutes in the boiling water canner before sealing.
Q. Is there a recommended process for cleaning jars before canning?
Jars to be used for canning can be cleaned by hand, or you can use a dishwasher. They are best cleaned with some detergent and hot water. After washing, the jars can be soaked in a solution of vinegar and water (one cup of vinegar/one gallon of water) to remove films created by hard water. It should be noted that washing jars should not be a substitute for sterilization.
Q. Should the jar be left to cool in the same water used for processing?
The ideal and standard procedure after processing is to remove the jars from the hot water bath canner immediately the processing time is reached. The canning jars can accommodate bacteria that survive the heat if they are left to cool in the hot water bath canner. These bacteria can cause canned food to go bad quicker than expected. In the case of a steam pressure canner, the heat source is stopped the recommended processing time immediately is reached and the canner removed. The jars are, however, left in the canner to cool down under steam pressure. During this time, any microorganisms that survived the processing are destroyed. The processed jars should not be cooled too quickly by putting them under running water, it is best to allow cooling to happen gradually.
Q. What causes the base of metal lids to become discolored?
Some foods stored in jars contain natural compounds that have corrosive properties. On contact with the metal surface of the lid, they can cause discoloration. It is, however, known to have no adverse or harmful effect.
The Visual Appearance of the Food
Q. Why does the color of canned foods change?
The changing color of canned foods is mostly due to chemical reactions such as oxidation which happens in the presence of air and moisture. Also, exceeding the recommended processing time can cause the color of canned foods to be different from what you expect. Some examples include the changes in the color of fruits such as apples, peaches or pears which is due to the chemical changes during the canning process. The constituents of some cooking utensils such as Iron or copper can also influence the color of foods they are used for cooking. In some cases, the liquid used in packing can alter the color of the food. It is also known that different varieties of a particular food, for example, corn, will have varying colors after processing. These are some common reasons foods in jars may have different colors.
Q. Are discolored foods in jars safe for consumption?
Discoloration of foods due to canning does not pose any danger to health except it has happened because the food is bad. You can determine if the food is bad from the smell or its appearance. However, if you notice changes in color, observe the food closely before eating.
Q. What is the importance of leaving headspace when canning?
It is important to leave headspace, the space between content in the jar and the lid, to accommodate expansion, and prevent spills during processing. If the headspace is not enough, the content of the jar can be deposited on the jar’s rim causing problems during sealing. Headspace creates a vacuum that prevents the discoloration of the food closest to the lid.
Q. What is the reason for the loss of liquid during processing?
You may notice a loss of liquid during processing when the canning jar is too full. This causes the internal pressure in the jar to be unstable. Also, repaid changes in pressure when there are still air bubbles can cause loss of liquid during processing.
Q. Is it necessary to replace lost liquid during processing?
Canned food will still be preserved if some liquid is lost; however, it is not advisable to reopen the jar because you want to replace the lost liquid. This action can allow bacteria into the jar, and the shelf life of your food will be reduced.
Q. Should home-canned foods with cloudy looking liquids be discarded?
If the liquid is cloudy; you should check the food to know if it had gone bad. Some liquids turn cloudy because of the presence of minerals in the water, or from the food, especially if it contains starch. Foods that have traces of foam and bad smells should be discarded.
Q. What is the best way to discard home canned food that has gone bad and how can the jar be cleaned properly?
Some canned foods have low acidic content while others can emit highly acidic. Depending on the food, you will need to follow different procedures for proper disposal and cleaning the jar. Here are some ideas you can use:
In the case of jars that are still sealed, you can dispose of by putting the jars in a garbage bag and into a trash can. Alternatively, you can bury the garbage bag in a landfill site.
However, if the seal on the jar has been compromised, you will need to detoxify the jar before disposal. Look out for signs of leaks or if the jar is apparently unsealed.
Here’s a guide to detoxifying the compromised jars before disposal;
Place the jar to be detoxified in a bigger pot, or the hot water canner. The jar to be detoxified should be placed on its side in the pot. Pour some water into the pot, enough to cover the jar at least one inch higher than the lid. Put the pot on a source of heat and boil for thirty minutes. This is enough time to detoxify the jar and its content. After cooling, you can discard the jar, and any cloth or materials you have used during the process.
Canning Equipment
Q. When should a pressure canner gauge be checked?
It is recommended that the pressure canner gauge be checked once every year. However, if you need to submerge the lid in water often, or notice signs of corrosion, then it should be checked promptly. Regarding the weighted gauge, there is no need to check it because it is fixed, but you should clean it after each use.
Fruits and Vegetables
Q. Is there any specific benefit of canning vegetables?
Absolutely, canning vegetables involve the use of heat during processing. This heat destroys bacteria such as botulin which may be present in foods such as meats, poultry, fish and vegetables. The canning process requires the use of temperatures as high as 240 degrees Fahrenheit. At this temperature, harmful bacteria will be destroyed.
Q. Is it necessary to use sugar or salt when canning fruits and vegetables?
It is not mandatory to use sugar or salt when canning vegetables. However, if the recipe you are using specifies the use of sugar or salt, you should adhere to the instruction.
Q. Is there an explanation for why fruits float in the liquid when canned?
Fruits in canned jars may float for different reasons. The air trapped within the fruit’s tissues may make it buoyant in the canning liquid. It is also possible that the pack is loose or the liquid used has a high density.
Q. Why is it necessary to acidify tomatoes before canning?
Naturally, the acidic content in tomatoes is quite high; it is at a pH level known to be unsafe for consumption, hence the need for tomatoes to be acidified. This is done by using lemon juice or some citric acid. If you decide to use lemon juice, the best choice is bottled lemon juice instead of fresh lemon juice which has a varying acidity level, measure one tablespoon for pints. And with citric acid, you will need about a ¼ teaspoon for one pint. Vinegar may also be used for this process; its measurement is four tablespoons per quart. However, vinegar may cause changes in the flavor. These quantities should be added into the jars before putting the tomatoes in for canning. The sour, acidic taste can be reduced by adding some sugar.
Q. What are the things to note when home canning tomatoes?
For home canning, it is best to avoid overripe tomatoes. The best choice should be ripe tomatoes with lots of juice in them. Also, have a good look at your tomatoes and remove any that has signs or rot or decay. The leaves or stems should also be removed. Then acidify the batch of tomatoes you have selected for canning.
Q. Can ascorbic acid be used to prevent fruits or vegetables from becoming discolored?
Yes, it can, ascorbic acid hinders the process of oxidation which is known to cause discoloration in fruits. You can add a ¼ teaspoon of ascorbic acid in the crystalline form to a quart of the fruits or vegetables to be canned.
Q. I observed traces of mold on my home canned fruits and vegetables can I still eat them?
It is strongly advised that you should throw away any home canned foods which have traces of mold. This mold could be an indication of the bacteria infection such as Botulin which is harmful to human health.
Q. Is it advisable to use artificial sweeteners when canning fruits?
It is not advised that you should use artificial sweeteners when home canning fruits. Instead, use water or fresh juice without sugar or artificial sweeteners for canning.
Jellies, Jams, and Preserves
Q. Why do the fruits float in jam when canned?
Fruits will float in jam when they were not ripe before canning. It is also possible that they have not been properly processed and crushed before canning. There is also the issue of improper cooking and packing in the jars. To avoid this issue, you can remove turn off the heat when the jam is cooked and stir/skim for about five minutes.
Q. Must jam be processed in hot water bath canners?
This is a mandatory process to prevent the growth of molds and prolong shelf life. It also improves the quality of the food.
Q. What is responsible for the formation of crystals in jelly?
Crystals can form in the jelly when the quantity of sugar used for the mixture is too much; crystals can also be formed when the mixture is left to stand after cooking the mixture too slowly. Crystals can be prevented by allowing the mixture to stand in a cool place for about eight hours; you can then strain the mixture with a damp cheesecloth.
Q. What are the mistakes that can make jelly too soft when processing?
Your jelly may be too soft because you have added excess juice to the mixture, or low acidity of the mixture. This usually happens when you attempt to make a large amount of jelly at once.
Q. How can jelly be made firmer and consistent?
You can harden the texture of your jelly and make it firmer by cooking it again following the recipe. However, it is best to make smaller quantities of jelly at a time, for example, five cups for each batch.
If you decide to use powdered pectin to make the jelly firmer, you can follow this recipe. Measure four teaspoons of powdered pectin, a quart of jelly, ¼ cup of sugar, ¼ cup of water. Make a mixture of pectin and water; boil this mixture while stirring to prevent scorching. Then add jelly and sugar, continue stirring, skim for a while and pour into hot jars. Seal the jars and proceed with the canning process.
Liquid pectin can also be used; in this case, you will need to measure two tablespoons of liquid pectin, a ¾ cup of sugar, two tablespoons of lemon juice, and the jelly to be cooked again. Boil the jelly with high heat; add sugar, lemon juice, and pectin while stirring continuously. After boiling the mixture for one minute, remove the jelly from heat, skim for a while and pour into hot jars, seal the jars and proceed with the canning process.
If you do not wish to use pectin, you can heat the jelly for a few minutes and skim to make it firmer, before canning and processing.
Q. Why does jelly sometimes turn out like syrup?
This could have happened due to insufficient pectin, or acid. Too much sugar can also turn your jelly into syrup.
Q. What is the cause of weeping jelly?
Weeping jelly is mostly due to excess acid, and heat. If the temperature in the area you stored the jelly fluctuates too often, this can also happen.
Q. What can make jelly too strong?
If you overcook your mixture, the outcome can be stiff jelly; also, adding too much pectin or using fruits that are not ripe can also make the texture of jelly too strong.
Q. Why does jelly ferment?
Fermentation is caused by leaks in the sealing, or if you have used very little sugar.
Q. Why is there mold on my jelly and jam?
In many cases, improper sealing can allow bacteria and air to enter the jar and cause molds.
Q. Why does jelly or jam become discolored at the upper part of the jar?
If your jar was stored in a very warm place, it is possible the seal has been compromised, and the air that goes into the jar can cause this discoloration.
Q. Why does jelly or jam fade sometimes in a jar?
This is due to the storage condition. If you store the jar in a place that is too warm for a long time, the fruits will lose their color.
Q. Why does jelly turn cloudy?
Cloudy appearance of jelly usually happens when it was poured too slowly into the jars after standing for a long time. The presence of pulp in the mixture can also make jelly cloudy. You can also experience this if you use fruits that are not yet ripe.
Q. Why is my jelly sticky?
This is caused by overcooking. It is essential that you follow the instructions on your recipe to avoid overcooking.
Q. Is it possible to use canned fruits sold commercially to make jelly?
Yes, it is possible. However, the best outcome can be obtained when you use a recipe that makes it mandatory to add pectin. This is necessary because the quantity of pectin in the canned fruits may be insufficient.
Q. What time is best to add liquid pectin when making jelly or jam mixture?
You should add the liquid pectin to the mixture immediately after removing the mixture from heat source.
Q. What is the best time to add powdered pectin to the mixture when making jelly or jam?
If you decide to use powdered pectin, it should be added to the crushed fruit before heating.
Q. What is the procedure for using paraffin to seal jelly?
This is no longer the practice due to the prevalence of mold growth when paraffin is used to seal jelly. Instead, use high-quality sealing lids which are adequate for processing in a hot water canner.
Q. Is it possible to double the recipe for jam or jelly?
No, it is not advisable to double the recipe you are using. This can lead to undercooking, and the jelly may be too soft. The outcome can also become discolored and caramelized.
Pickles and Relishes
Q. What is the best container for processing and canning pickles?
Pickles should be processed in glass jars, aluminum or stainless steel jars. You can also use good enamelware; however, avoid the use of containers made from iron, brass or copper as well as galvanized containers, to prevent pitting.
Q. Is it possible to alter recipes for pickles or relish successfully?
The standard recipes for pickles and relish have been made to ensure the right quantity of vinegar, water, and the food can prevent high acidity and growth of the botulin bacteria. So it is best you adhere to the recipe.
Q. Why do my pickles have a bitter taste?
Bitter tasting pickles could be due to the following reasons:
- How they were grown
- The species of pickles some have a bitter taste.
- Soaking pickles in brine for a short time can help to reduce the bitter taste before you can.
To find out if the pickles you are about to can taste bitter, take a bite from the parts around its stem, if it tastes bitter, and cut off the parts close to the stem since this is where the bitter juices are concentrated in the pickles.
Q. Why are some pickles hollow?
Hollow pickles are usually due to premature or undeveloped cucumbers. Also, fermentation or the use of brine that is too strong or weak for fermentation can cause hollowness in pickles.
Q. Why are pickles sometimes soft or slippery?
The soft or slippery texture you feel on the surface of pickles is mainly due to the action of microorganisms which spoils the pickles. Microbial activity is usually prevented by adding salt or acid in the right quantity. Pickles can also become soft when they have not been adequately heated or if the seal is broken. It is also important that the blossoms are detached from the cucumbers before the fermentation process, because they may contain fungi or other microorganisms.
Q. What causes discoloration in pickles?
Some of the reasons pickles become discolored include the use of excess spices, iodized salt, water rich in iron, and utensils made from iron.
Q. What makes pickles shrivel?
Pickles can become shriveled due to overcooking and when you use concentrated vinegar, or solutions made with excess sugar or salt when pickling. The best practice is the use of the diluted solution, and the concentration can be gradually increased until the desired content is achieved.
Q. Why is it important to process pickles in hot water bath canners?
This is necessary because the heat in the hot water bath canners destroys the microorganisms that can make the pickles go bad, lose firmness or color.
Q. Why does sauerkraut lose its color and become darkened?
Discoloration of sauerkraut may be due to reasons such as exposure to air, wrong fermentation process, failure to wash and trim the cabbage properly, excess or too little salt, or lapses in the processing and storage.
Q. Why does sauerkraut become soft?
Some conditions that can make sauerkraut too soft during processing include excessively high temperature during the fermentation process, presence of air pockets due to wrong packing methods, and the insufficient salt during processing.