Canning Tips & Techniques

Download: The USDA Complete Guide to Home Canning

Foods that are being canned fall into two different canning techniques. High acid and low acid. High acid foods can be canned in a boiling water canner, while the low acid foods can only be canned safely in a pressure cooker. Our site deals only with high acid foods that are done in the water bath.

Low Acid Foods
Low acid foods (pH higher than 4.6) such as vegetables, meats, seafood, soups, and sauces can't combat the harmful bacteria at the low temperature of a boiling water canner (212*F).  They need the high temperature of a pressure canner (240*F) to be canned safely. When canning vegetables (beets, cucumber etc.), the acid level is brought higher when pickled with vinegar, and can safely be canned with the boiling water bath

High Acid Foods
High acid foods (pH lower than 4.6) such as fruits, jams, jellies, pickles, relishes, chutneys, and acidified tomatoes can all be safely canned with the boiling water bath technique. The 212*F temperature is high enough to kill any bacteria that can survive the high acid. There is another important issue when canning... time. The food being processed must be boiled in the canner for the exact time on the recipe or you run the chance of not killing all the natural yeasts, enzymes, and microorganisms.

Canning Jars
It is important to not use just any jar for canning. You must use a proper canning jar with the proper 2-piece lid to ensure an air tight seal. Discard any jars that are nicked on the thread or are cracked

The 2-piece lid consists of a sealing cap and a screw cap. The screw cap can be reused but always use new sealing caps to ensure an air-tight seal. Boiling the lids is no longer required. Heat to 180*F/82*C only. They must be placed on the jar hot for a proper seal. There is no preparation needed for the screw cap as it doesn't come in contact with the food

Visit the Bernardin site for all your canning needs


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Step by Step Guide to Canning with a Boiling Water Canner

Sterilization of Empty Jars
To sterilize empty jars, place them right side up on the rack in a boiling-water canner. Fill the canner and jars with hot (not boiling) water to 1 inch above the tops of the jars. Boil 10 minutes at altitudes of less than 1,000 feet. At higher elevations, boil 1 additional minute for each additional 1,000 feet elevation. Remove and drain hot sterilized jars one at a time as filled.

Heat lids in hot water at 180*F/82*C only. They must be placed on the jar hot for a proper seal. There is no preparation needed for the screw cap as it doesn't come in contact with the food.

Food Preparation
Select the best fruit and vegetables for canning. Overripe and blemished fruit and vegetables shouldn't be used. To prevent some fruit from discolouration, use commercial ascorbic acid and citric acid mixtures such as "Fruit Fresh" according to directions.

Filling the Jars
Use of a canning funnel is recommended. It has a wide mouth to match up with the jar opening.

  • Hot Pack
    Hot pack means the food is hot going into the jar. Whether it is cooked, like relish, or brought to a boil, like jam, it goes into the jar hot

  • Cold Pack
    Cold pack means there was no cooking of what you are canning. Pickles are an example of that. Just place the cucumbers in the jar after being washed and add the remaining ingredients and pour the hot liquid over top and process

Always remove the air bubbles by sliding a wooden or non-metallic utensil down the side of the jar. You may have to adjust the headspace after releasing all the trapped air

This is the space at the top of the jar. It is measured from where the lid sits and goes down. 
Headspace differs depending on what you are processing. For proper sealing, use the following guidelines


Jam & Jelly - 1/4" Pickles & Tomatoes - 1/2"
Fruit - 1/2" Relish, Salsa and Chutney - 1/2"

Clean the Rim
Wipe the rim with a clean damp cloth to remove any stickiness and anything that would hamper a good seal 

Place the sealing cap on the jar. Apply the screw cap only until resistance is felt. Overtightening may cause seal failure

When all the jars are filled and are ready for processing, lower the jars into the boiling water canner making sure the jars are completely submerged with at least 1" of water over the top. Place the lid on the canner and bring back to a boil. When the water returns to a boil, start counting the processing time according to the recipe. When the processing time has finished, turn off the heat and wait for the rolling boil to stop. Gently remove the jars from the water without tilting and place on a dish towel to cool. Let cool 24 hours. While cooling, you'll here the pop of the lids being pulled down. That sound is the sound of a good seal. If the sealing cap isn't pulled down, the jar needs to be reprocessed. If after a second processing doesn't give you a good seal, refrigerate and use first.




Boiling Water Canner

Canning Equipment

Processing Time
Processing time depends on the altitude you're at. The higher the altitude, the longer the processing time. Please adjust your recipe as follows

Lesley's Hot Dog Relish

Altitude Increased Processing Time
Feet Metres Increase by:
1,001 - 3,000 306 - 915 5 minutes
3,001 - 6,000 916 - 1,830 10 minutes
6,001 - 8,000 1,831 - 2,440 15 minutes
8,001 - 10,000 2,441 - 3,050 20 minutes



  • Tomatoes are normally considered high in acid, but the acid level isn't quite high enough for canning. To bring tomatoes up to the proper acidic level, vinegar, lemon juice or citric acid must be added. Add 4-tbsp vinegar, 2-tbsp of bottled lemon juice or 1/2-tsp of citric acid per quart of tomatoes. For pints, use 2-tbsp vinegar, 1-tbsp lemon juice or 1/4-tsp citric acid

  • Processing time doesn't start until the canner is brought back to a rolling boil

  • Spoilage signs are a swollen lid, leaky jar, and discolouration of the food. Never eat food from the jar with these signs. If the lid isn't pulled down in the sealed position, discard. 

  • What is Pectin?
     Pectin is a natural product found in the skins and cores of fruit. The commercially prepared pectin is usually made from waste citrus peel after juicers are finished with the crop. 
    The reason for adding pectin to jams and jellies is that the pectin helps the fruit gel. Some fruits are naturally high in pectin and can be made into jelly without the assistance of pectin. Some examples of high pectin fruit are tart apples, crab apples, gooseberries and cranberries. When a fruit is just about to turn ripe, the pectin level is at its highest, so if a high pectin fruit is going to be made into jam without the assistance of added pectin, the best time to do this is when the fruit is ĺ ripe.
    There is a ratio of sugar to pectin that must be kept if the fruit is to gel. Thatís where a good proven recipe comes in. This ratio is already set in the recipe. 
    There are two types of commercially available pectin, liquid and powdered. These have different properties and canít be interchanged so stick to the type of pectin in the recipe.
    A good standard to adhere to is to purchase fresh pectin each year. Old pectin may result in poor gels

  • Big Dave wrote in with this handy tip:
    I found a old fashioned trick for checking pickling brines for sufficient salt.
    You put a raw egg into the brine and when it floats there is enough salt

Canning Links

Virginia Cooperative Extension

North Dakota Extension Service
MU Extension
Clemson Extension
National Center for Home Food Preservation
A Guide to Home Canning (great links page)


The USDA Complete Guide to Home Canning
Downloaded from Penn State University (pdf format)
Principles of Home Canning
Selecting, Preparing and Canning -- Fruit and Fruit Products
Selecting, Preparing and Canning Tomatoes and Tomato Products
Canning Vegetables and Vegetable Products
Preparing and Canning Poultry, Red Meats, and Seafoods
Preparing and Canning Fermented Foods and Pickled Vegetables
Preparing and Canning Jams and Jellies