THE PRESSURE CANNING TYPES AND FEATURES

Before I get into types of equipment used for pressure canning,unlike the boiling water bath canning where temperatures don't have to exceed 212 degrees and foods are high in acidity,the pressure canning method processes low acid foods but at the considerably high temperature of 240 degrees at a specifc pressure and time. This method utlilizes a heavy kettle and includes a locking tight fitting cover which enables the pressure canner to be airtight. This entire process is to ensure food will be protected by eliminating hard to kill microorganisms in particular botulism.

You will notice in the pictures below two types of pressure canners. They have a different method of measuring pressure in your canner one being a dial gauge and the other weighted gauge. I will be comparing on this page both the advantages and disadvantages associated with each design.

There are two types of covers available for these pressure canners either the locking cover or metal to metal canner. The locking cover has a gasket and over a period of time may start to become out of round. The gasket can become dried out or cracked all of this can prevent your canner from reaching the required temperature. I would remove the gasket from the cover after each use and give it a thorough cleaning in very hot and soapy water and let dry completely. Earlier gasket canners required a light coat of vegetable oil at least once a year but now most models come with a prelubricated gasket and oiling will have no benefit. However check your canner's manual to make sure you have a prelubricated gasket.

You might have inherited someone's old canner and now have decided to try your hand at canning. The metal to metal cover is simply a canner with wing nuts. You always tighten the two wing nuts on opposite sides of the canner at the same time. The process is repeated for the two remaining wing nuts.

As can be seen from the graphics below there are two types of gauges that could be on the canner you have purchased one being a weighted gauge and the other a dial gauge. The weighted gauge allows you to cook away without paying attention to the pressure. It releases small amounts of steam everytime it wiggles and rocks. If you are an avid cell phone fan you can continue your text messaging while your food is processing. This is not the case with the dial gauge you must check the dial gauge to make sure that steady pressure is being maintained at or slightly above the correct gauge pressure. This is accomplished by regulating the heat on your electric or gas stove. This takes a little more alertness than the weighted gauge but it all depends on your devotion to food processing.

THe sound of the weighted gauge rocking or jiggling acknowledges the weighted gauge pressure canner is maintaining the proper pressure. The single disadvantage to this type of pressure canning is that the weighted gauge canners cannot correct precisely for higher elevation. It is important to make sure the gauge includes a 5,10 and 15 weight mark on the gauge and you have the weights shown above that correspond to these numbers. The weights are usually found directly beneath the gauge. This was the reason I had difficulty with the pressure canning altitude chart that I am providing below.

There are several other facts you should be aware of when pressure canning. Canner internal temperatures are definitely lower at higher altitudes and canners should be operated at the increasing pressures specified below. We have not included the weighted 5 because I concluded there is very little to be canned at that pressure so rather safe than sorry.

There can be trapped air in your pressure canner and this will lower the temperature obtained at all levels of pressure including 5,10 or 15 pounds and can result in under processing. The highest volume of trapped air is in processing raw packed foods in a dial gauge canner. Unlike the weighted pressure canner,the dial gauge has no way to vent during processing.

To vent a canner you can leave the vent port uncovered on recent models or manually open the petcocks on older designs. Before venting your pressure canner make sure your jars are placed in the canner,it would be a waste of time to vent then need to open to place your jars in the canner before proceeding with pressure canning. You would have again introduced air into the canner.When the steam begins to escape turn on your timer and set for 10 minutes. When the timer goes off,at the end of ten minutes recover the vent port or close the peacock.I WOULD CONSULT YOUR PRESSURE CANNER INSTRUCTIONS FOR ANY VARIATIONS OR DIFFERING INSTRUCTIONS FOR YOUR PARTICULAR CANNER CONCERNING THIS AND ALTITUDE DIRECTIONS

THESE STEPS SHOULD BE FOLLOWED FOR SUCCESS IN YOUR PRESSURE CANNING

The pressure canning rack is quite a different design from the boiling water bath canning rack. The rack should be stable when placing it in the bottom of the canner. A stable rack keeps the jars in place and avoids the unthinkable of falling over,touching other jars or touching the sides of the canner. The additional equipment other than the rack and the canner itself is basically the same equipment as reviewed on the home canning page click here to review the equipment

I do have to note here that some of these pressure canners are not recommended for glass top stoves because of the weight. They could end up cracking your glass or because they are somewhat wider than most glass top burners an uneven heat may occur or cause additional damage to your glass top. PLEASE CONSULT YOUR MANUAL OR CONTACT THE MANUFACTURE OR IF PURCHASING A CANNER CONSULT WITH THE MERCHANT FOR ADDITIONAL INFORMATION. Now that you have read this far you may as well finish sorry about the glass top information but better here than never.

Your food should be completely washed prior to precooking or packing it in the jars. Your pressure canning should always begin with fresh quality of foods. Follow your recipe to find the correct yield in order to manage your batches. Place your commodity into HOT JARS and keep your jars hot by having them in another pot containing hot water. Using your jar lifter, remove the jars one at a time and place them in your canner.

A LITTLE DIFFERENT APPROACH IN PRESSURE CANNING

You could not stack one-half- pint or pint jars in boiling water bath canning. Here using an additional rack on the top of the first layer of jars. This is only possible if your canner is large enough to accept a two layer height. I would rearrange the second layer jars so they do not sit directly above the first layer. This will allow good air circulation for reaching the successful required pressure and temperature. I am going to provide a step by step method of loading,processing and unloading your pressure canner. This by no means relieves you of your responsibility to check YOUR MANUAL BEFORE PROCEEDING WITH PRESSURE CANNING

1. Ladle your boiling water or liquid from precooking the vegetables into the jars.
2. Release any air bubbles with your nonmetallic spatulua.
3. Place the lid on your jar sealant side down and secure with a screw band.
4. Place the jars in your canner with a jar lifter check your manual for the correct amount of simmering water in your canner.
5. The moving of jars with a jar lifter requires that lifter is secured below the neck of the jar which is just below the screw band of the lid.
6. You must keep the jar upright at all times. You don't want food to spill into the sealing area of the lid.
7. Fasten the canner cover securely leaving the weight off the vent port or open petcock.
8. If working with a weighted gauge canner in lieu of a dial gauge consult the manual for any pre-venting if required.
9. The heat setting on your stove should be turned to its highest position. This should continue until water boils and steam begins to flow maintain this for 10 minutes.
10. After 10 minutes replace your dial gauge or close the petcock on your canner
11. Processing times begins when the gauge reaches the recommended pressure for your recipe or in the case of a weighted gauge when it begins to jiggle or rock*
12. The timed process is complete you will turn off the heat and remove the canner from the stove. It may take as long as thirty minutes or more for cool down
13. A word of caution here if you decide to remove the canner from heat make sure you don't tilt the jars.
14. Older canner models or weighted gauge models should be timed because of thicker walls and no dial gauge.
15. Allow at least 30 minutes for pints and forty-five minutes for quarts for 14 above.
16. On a dial gauge canner wait an additional fifteen minutes after the gauge registers zero.
17. Again consult your manual remove the lid carefully with the cover opening away from you allowing the steam to flow way from you.
18. Don't immediately remove the jars but wait at least another 10 minutes before doing this.
19. Use your jar lifter to remove the jars from the canner placing them on a clean towel with two inches of space between jars.
20. A complete cooling of the jars make require 12-24 hours.
21. Remove ring bands after complete cooling and store
22. Test your cooled jar lids by pushing on the center** Clean all equipment.

    NOTES TO REVIEW * IF YOUR PRESSURE BEGINS TO DROP WHILE PRESSSURE CANNING THE TEMPERATURE WILL DROP WITH IT. THIS CAN BE FIXED BY INCREASING THE HEAT. AFTER THE PRESSURE HAS BEEN RETURNED TO ORGINIAL TEMPERATURE SETTING,RESTART YOUR PROCESS TIME FROM THE BEGINNING.

    **IF YOUR LID SEEMS TO BE SOLID AND NO DENT IS PRODUCED THEN YOU HAVE A SUCCESSFUL SEAL.IF THE LID DEPRESSES WHEN YOU APPLY PRESSURE THAN THE LID FAILED TO SEAL.YOU MUST PUT THESE IN YOUR REFRIGERATOR IMMEDIATELY AND USE THE CONTENTS WITHIN AT LEAST TWO WEEKS

    Below is table for preparing some vegetables by the pressure canning method. I tried to pick what I thought were the most common vegetables someone might care to jar. I am sure there are others.

    PRESSURE CANNING YOUR FAVORITE VEGETABLES

    VEGETABLE	REMARKS	QUANTITY	HOT PACK	HEADSPACE	PROCESSING TIME
    Potatoes	Boil in large pot for ten minutes Drain reserve liquid. Pack into jars add rederved liquid	5 pounds for quart jar	The Best	One inch for liquid and potatoes	10 pounds thirty minutes pints/40 quarts
    Sweet Potatoes and Yams	Cook in boiling water until peels rub off Pack in jars with clean boiling water or syrup mixture 2-one half cups sugar/5 and one quarter cups of water boiling	TWo and one half pounds to three 1 quart jar	The Best	One inch for liquid and potatoes	10 pounds 1 hour five minutes pints/1 hour 40 minutes/quarts
    Carrots	Slice or keep carrots whole. Simmer in boiling water five minutes.Pack hot into jars using cooking liquid	Two and one half pounds 1 quart tops removed and peeled	The Best	One inch carrots and liquid	Ten pounds 25 minutes pints/30 minutes quarts
    Green Beans Any	Raw Pack washed beans in jar pack tightly cover with boiling water. Hot pack Add beans to boiling water 5 minutes add beans to jars with boiling liquid	One and one half to two pounds for 1 quart	Both Hot Pack And Raw Pack	One half inch liquid and beans	10 pounds for 20 minutes pints/25 for quarts
    Bell Peppers	Remove stem,core and seeds. Cut into large 2 to 3 inch pieces. Boil for three minutes. Drain and pack right away. Add to the jar one tablespoon of bottled lemon juice and then fill jar with boiling cooking liquid	Three- four pounds for a 1 quart jar	The Best	One inch for pepper and one-half inch for liquid	10 pounds for 35 minutes pints
    corn	Discard husks and silk. Use a sharp knife and cut the kernels off the ear. Measure the corn and for each pint add 1 cup of boiling water,each quart two cups of boiling water. Boil for five minutes more and transfer to jars.	Four to five pounds(weighed with husks on) to one quart jar	The Best	One inch for corn and liquid	10 pounds for fifty-five minutes pints/1 hour and 25min quarts
    Peas	Remove peas from pod add to boiling water. Small peas one-quarter in diameter three minutes,medium with a one qusrter to one- third diameter 5 minutes. If peas are larger than one-third add 10 minutes for pints and quarts. Remove peas and rinse in colander with hot water then pack in jar adding the boiling cooking liquid	Four to five pounds for one quart jar	The Best	One inch for peas and liquid	10 pounds for 40 minutes both pints and quarts

    This I believe concludes the page on pressure canning. I would like to point out that Gardeners Gardening used its best information in preparing this web page but we make no warranties as to accuracy or in fact its completeness. It is up to the reader to read the manual that comes with your appliance like a pressure canner because rules could change with the piece of equipment purchased. Gardeners Gardening or its principals shall not be held liable for damages in any misuse of equipment or flawed preparation of food. It would be good to research further on the Internet for additioanl information on pressure canning.

    REVIEW OF LINKS ASSOCIATED WITH HOME CANNING

    Since this such a detailed subject I have provided the two links below to review both home canning and boiling water bath canning:

    go to home canning

    go to boiling water bath canning

    RETURN TO HOME FROM PRESSURE CANNING

    

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