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Canning Food in Mason Jars - Tips and Warnings

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Peg Cole is a self-taught cook who shares her favorite recipes and methods of cooking and baking.

Fresh Tomatoes

Fresh Tomatoes

Canning Methods

There are three main methods used in canning: the hot water bath; use of a pressure cooker and the open kettle. The type of food to be preserved determines which way the way heat is to be applied.

The hot water bath is recommended for high acid foods like fruit and tomatoes; never for low-acid foods like vegetables and meat. These require temperatures which are obtained only under steam pressure.

The use of a pressure cooker or pressure canner is recommended for meat, poultry, fish and most vegetables excluding tomatoes.

The open kettle method is a process where food is cooked in a kettle then transferred to sterilized mason jars and sealed. It can be used for preserves, pickles and vegetables with high vinegar content or containing high levels of sugar, which helps fruit hold its color and flavor.

Home canning equipment may consist of a large (23 quart) covered pan with the addition of a metal rack insert designed to hold various sized Ball Jars. This functions as a hot water bath for food processing.

Canning 101

Keys to Success

Foods that can be safely canned in boiling water bath include jams and jellies, pickles, applesauce or apple butter, non-meat spaghetti sauce, tomatoes and ketchup due in part to their high acidic value and or the addition of vinegar to assist in preserving.

The key to success in canning food at home is knowing which foods are safe to preserve and which foods are not. No one wants a raging bout of food poisoning or botulism from the “toxin sometimes found in foods improperly canned or preserved”.1

Botulism is a serious poisoning that is often fatal. It’s important to note that simply boiling food is not enough to prevent the growth of microorganisms like Clostridium botulinium, which is destroyed only at the temperature of 240 degrees (10 lbs. pressure) or higher.

Food spoilage is caused by yeast, molds and bacteria which can be nearly destroyed by a process of heating, however, no preserved food will last indefinitely. Shelf life will vary based on the type of food preserved and even on the levels of fungus and mold contained in the air. No kitchen is completely sterile.

Fresh Produce and Canned Food



Pressure Cookers

Pressure Cookers or Pressure Canners before the 1970s were thick walled and heavy with clamp-on or turn on lids. Design and safety of this home canning aid has vastly improved since that time. Modern pressure canners are lightweight with removable racks, a dial gauge and a safety fuse. To be considered a pressure canner, this equipment must be able to accommodate at least four one-quart jars.

Home canning using a pressure canner is fraught with a possibility of serious errors resulting from under processing, such as when an inaccurate dial gauge is used. Gauges should be checked for accuracy yearly. Altitude also plays an important part in maintaining correct internal pressure and temperature on canners operated above sea level. Adjustments must be made to compensate as altitudes increase. Other pitfalls may include trapped air in the canner during processing, resulting in under processing. Loss of pressure during the process can also result in unsafe food unless the pressure is corrected and the timing of the process starts over. Forced cooling of the pressure cooker can also result in food spoilage. The USDA maintains strict regulations for food safety reasons.2

Ball Mason Jars © PegCole17

Ball Mason Jars © PegCole17

Preparation for Home Canning

Early glass jars began to appear between the years 1840 to 1850. The Ball Brothers Glass Manufacturing Company started producing jars in 1884 in Indiana where the supply of natural gas used in the manufacture was abundant. Also known as fruit jars, the term Ball jar became a household name although there were other manufacturers like Kerr and Mason.3

Jars intended for use for preserving fruits and tomatoes should be inspected carefully for chips or cracks. Thoroughly wash each jar with detergent, rinsing well, then invert on a clean dish towel. Never use a towel that has been used for hand drying as this may introduce bacteria. If the jars are used in a hot water bath or a pressure canner, the process will provide sterilization. New rubber rings should be used with metal screw bands and inner lids should have rubber seals that are completely intact to form a good seal.


Fresh Blueberries

Fresh Blueberries

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Tips on Fruit Selection

Select fresh fruits or vegetables and sort them according to size and the degree of ripeness. Very ripe fruit should be used only for juices rather than for preserving. Any fruit or vegetables that have signs of decay should be discarded as this will lend to bacterial growth.

Avoid mixing different types vegetables in the same jar. It's safer to preserve vegetables separately and mix them later. Wash the fruit or vegetables thoroughly to remove any dirt, fertilizer or pesticide residue.

Work quickly following the rule of thumb two hours from garden to can. Avoid soaking food for long periods of time as this can encourage bacterial growth and lessen the nutritional value.

Sugar syrup is used to prepare a variety of fruits but is not necessary to keep them from spoiling. Different proportions of syrup mixtures range from thin (1 cup of sugar to 3 cups of water) for soft fruit like berries or sweet cherries, or medium (1 cup sugar to 2 cups of water) for acid fruits like peaches or apricots or rhubarb and regular cherries. Heavy syrup (1 cup of sugar to 1 cup of water) is used for large sour fruits.

Canning Kit


Preparation for Peaches

Canning time tables for fruits and tomatoes vary with each type of fruit selected.

Blanch the fruit in boiling water to aid in the removal of the skin of the peaches. Cut the peaches in half and remove the pit. Pack into clean jars and add syrup mixture to within one inch of the top of the jar. Or, precook for three minutes in a syrup mixture before placing in the jars.

To adjust the lids on the glass containers screw them on tight, then, turn them back almost a quarter turn. Place the jars in a hot water bath at 212 degrees F.

Style of Pack 

Jar Size 

0- 1,000 ft 

1,001-3,000 ft

3,001-6,000 ft

Above 6,000



20 min 

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25 min 

30 min 

35 min 

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25 min

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35 min 

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30 min

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Water bath canner

Water bath canner

If using a pressure canner, follow the directions provided with the equipment. After removing the jars from the hot water bath with a jar lifter, being careful not to tilt the jars, set them upright on a surface covered with a towel. Allow ample space of at least one inch between the jars to avoid slow cooling that may encourage the growth of bacteria.

Avoid placing them in a draft or on a cold surface to keep the jars from breaking and leave them undisturbed while they cool, usually between 12 to 24 hours. Do not tighten the ring bands until the jars are completely cooled. 4

Test the jars for leaks by tapping the center of each lid with a teaspoon. If there is a proper seal, there will be a clear ringing sound. A poor seal results in a dull flat sound. Place any unsealed jars in the refrigerator and use first. Don’t press down on the center of the metal lid before the jar is completely cool. Be sure to label the jars with the date and contents before storing in a cool, dry place out of direct light.

Fresh produce

Home canning can be fun and economical when proper techniques and procedures are followed. Be sure to consult the USDA Complete Guide to Home canning for exact time charts and more information on the type of food that is to be preserved.

A variety of recipes and time tables are available on-line from any State University Agricultural Department.5


1 Webster’s New World College Dictionary, Fourth Edition, 2002

2 Elizabeth L. Andress, Ph.D., Professor and Extension Food Safety Specialist, University of GA

3 History of Ball,

4 Mirro Cook Book, Fourth Edition, Approved recipes from the Mirro Test Kitchen

5 Texas Agricultural Extension,

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2011 Peg Cole


Peg Cole (author) from North Dallas, Texas on December 31, 2014:

Hi DzyMsLizzy, I agree that the potential for trouble with pressure canning is always a consideration. One of my friends came to work one day with little burned places all over her arms, neck and face from a bad experience with a pressure canner. Freezing veggies is often the way to go. Non mushy is my very favorite kind of vegetables.

Liz Elias from Oakley, CA on December 30, 2014:

I just re-supplied my canning stuff this year. I only do water-bath canning. I will not do pressure canning; there is too much room for error and trouble, and then they tell you to boil your home-canned veggies for 10 minutes anyway--that virtually makes them inedible, non-nutritious mush, so no thanks. For those kinds of veggies, I freeze not can.

Voted up and useful.

Peg Cole (author) from North Dallas, Texas on December 30, 2014:

Hello Mary, thanks for sharing your canning experiences here. With a garden it pays to know how to can food. It's been a while since I made any preserves but we loved to make strawberry preserves back in the day.

Mary Hyatt from Florida on December 30, 2014:

I learned how to can from my Mother. We had a large veggie garden, and we canned a lot. We also put up jellies and preserves. You wrote a very informative Hub.

Voted UP, etc.

Peg Cole (author) from North Dallas, Texas on July 01, 2014:

Hello Moonlake, We freeze a lot of our excess produce now, too. It is a lot of work to can foods but when you do take the time, it's well worth it. Thank you for dropping by and for sharing and voting.

moonlake from America on June 30, 2014:

We use to can all the time when the kids were young. Now we just freeze. This year I don't think we will get any of it done. Enjoyed your hub and your photos. Voted up...Shared on G+

Peg Cole (author) from North Dallas, Texas on February 06, 2014:

Hi there Rap. You know, I did most of my canning at an early age, too. It brings back such fond memories to think of my Grandmother and Aunt Jessie in the kitchen when we "put up" tomatoes or preserves. Good times. Here's hoping for a great growing season and lots of veggies to can. Thanks for coming by.

Ruth Perkins from New England on February 06, 2014:

Yes as you describe in this very informative hub proper canning is essential to safety. I used to can when I was a teen but now that I am a busy grown -up I do not. I reviewed your hub to refresh my canning skills & have chosen to use the simpler forms of food preservation that I have come to know. Thanks for reminding me how correct canning is crucial. Even though I do not can I congratulate all of you on your canning skills & patience. Happy Gardening!

Peg Cole (author) from North Dallas, Texas on July 31, 2012:

Hello Mvillecat. Thanks. I hope you will document the whole process and write a hub about it. Pressure canning is coming back with all the home gardens popping up. Awesome.

Catherine Dean from Milledgeville, Georgia on July 30, 2012:

Very informative. I have began canning for the first time this summer and I love it. I am just doing water bath canning at this point. I do want to go to pressure canning soon. Thanks!

Peg Cole (author) from North Dallas, Texas on July 22, 2012:

Hi Patsybell,

So nice of you to stop by and comment. Thanks for sharing and tweeting as well!


Patsy Bell Hobson from zone 6a, Southeast Missouri, USA on July 22, 2012:

very helpful. I'll bookmark this site for reference. liked, tweeted, pinned.

Peg Cole (author) from North Dallas, Texas on April 04, 2012:

Wow, I may need to come to your house for a refresher course in canning. There have been a few jars of mine where the contents grew unwanted stuff. Not a good sign. Thanks for reading and I'll be over later to borrow some canned goods.

Sheila Brown from Southern Oklahoma on April 03, 2012:

Great information! I think you covered all the bases. We can every year, tomatoes,green beans, black-eyed peas,etc. Every now and then I will find a jar that has come "unsealed" for some reason. Probably something wrong with the rim or the seal. You did an excellent job here! Voted up, useful and sharing! Have a great day! :)

Peg Cole (author) from North Dallas, Texas on August 31, 2011:

Hi Debby,

Thank you. Yes, when everything ripens at the same time it gets pretty busy in the kitchen. When the strawberry fields would open to "u-pick" my Auntie, GrandMom, Mother and I would gather flats of berries. Afterward, everyone had jobs washing jars or cutting fruit or stirring the jam. Good times. I can still smell it.

I'd love to try making some apple butter. Nice to meet you too!

Debby Bruck on August 29, 2011:

Nicely presented information. The fruits and veggies all ripen at the same time and must be canned before they go bad. Don't forget the apple butter! Nice to meet you Peggy.

Peg Cole (author) from North Dallas, Texas on July 28, 2011:

Hi Minne, With tomatoes you are usually pretty safe because of the acidic nature and recipes that contain vinegar. But it is a lot of work. It's a wonder if our grandmothers had any free time at all. Work work work.

Linda Rogers from Minnesota on July 27, 2011:

Hi Peg and thanks so much for the great information on canning. I have always wanted to can tomatoes from my garden but I think the worry of doing it wrong and poisoning the family overrides the want. LOL

Peg Cole (author) from North Dallas, Texas on July 24, 2011:

Thank you my friend Prasetio30. You are very welcome and I appreciate your visit here. Take care.


prasetio30 from malang-indonesia on July 23, 2011:

I love this hub. Very useful for us. Actually,I had never knew about this before. Thanks for share with us. Vote it up!


Peg Cole (author) from North Dallas, Texas on July 22, 2011:

Tina, Hello. I canned a lot of fruit and preserves in my time too. It is a lost art to prepare our own food and I am so glad my elders passed this on to me. It may just come in handy. Thank you so much for commenting.

Peg Cole (author) from North Dallas, Texas on July 22, 2011:

Lynda, I almost did poison us. I remember canning some pole beans and I didn't have a pressure cooker, just a hot water bath. Months later I discovered mold in some of the jars. Yikes. I had no idea of what I was doing and I certainly didn't go to the library and research it. Now it's so easy to learn with the internet.

You have got that right with the amount of work involved. But there is a certain satisfaction once it's all over and those glass jars are lined up on the pantry shelves.

It is so nice to see you out here again. I miss some of our old Hub friends. How are things in Florida?

lmmartin from Alberta and Florida on July 22, 2011:

Years ago, when I had a small farm, I did a lot of canning and managed not to poison my family. Your tips are great, and I recommend them to anyone starting out. As for me, too much work. Why does everything ripen at the hottest time of year? Those memories of slaving over a canning steam bath, slicing, dicing, boiling, sterilizing... all at 85 + degrees. No thanks. Been there/done that. Great hub though. Sorry it set me off on this whining jag. Lynda

Christina Lornemark from Sweden on July 22, 2011:

This is so good information about technics that are almost forgotten since we don't do this so much in our homes. I haven't done it for years, and when I did it was only berries in sugar. We need to know how to take care of food and we should do it more often. The best way to know what we eat is to follow the food all the way! Thanks for this useful hub!


Peg Cole (author) from North Dallas, Texas on July 21, 2011:

b. Malin, You are the sweetest! Thanks so much. You made my day. I think people are going back to basics now to avoid the additives in processed food. Canning may be a key to better health.

b. Malin on July 20, 2011:

I always know that I'm going to learn something of Interest when I come to your Hub Page PegCole. I've never canned before...but after reading your very informative Hub, I just might be tempted...I feel so Educated now!

Peg Cole (author) from North Dallas, Texas on July 20, 2011:

Gypsy, I will check it out. Sounds great. Forgot to mention that I used to make pickled green tomatoes and pickled watermelon rind too. Ooooh so good.

Gypsy Willow from Lake Tahoe Nevada USA , Wales UK and Taupo New Zealand on July 20, 2011:

If you like preserves, check out my green tomato marmalade recipe. I usually have lots at the end of the season. It is very popular with the family at breakfast time and even with meat. Yes memories are made of this, good ones!

Peg Cole (author) from North Dallas, Texas on July 20, 2011:

Hi Gypsy - Me too. It's been years. I used to love putting up jams and jellies the most. We often made guava jelly from wild guavas and mango-pineapple preserves and strawberry preserves too. The best part was that my Aunt Jessie and Grandmom were in the middle of the whole process. Fond memories.

Gypsy Willow from Lake Tahoe Nevada USA , Wales UK and Taupo New Zealand on July 19, 2011:

I haven't done this for years but your hub is tempting me to try it again. Thanks.

Peg Cole (author) from North Dallas, Texas on July 19, 2011:

Hi there Cygnet

I saw something from you yesterday in the mail. Hope things are going well with your new book and sales on the first one as well. So nice to see you here. And you're right about taking the power back. Yea.


cygnetbrown on July 19, 2011:

Hi Peg,

It's great to see that you are back into canning. I can't tell you how wonderful it is to see canned foods lined up on the pantry shelves. It's like taking power back from the grocery store.

Peg Cole (author) from North Dallas, Texas on July 19, 2011:

Hello Food Buzz, Nice to meet you here and I hope to see you again soon. Your hub on quick breads was very enjoyable and well written.

Hi Nell Rose, It's a real pleasure to find you on this page today. Thanks for stopping in to comment. I did some canning in my younger days as we lived in an area with U-pick farms with snap beans, strawberries, tomatoes, mangoes etc.. At the time, I thought boiling the stuff would be enough. I'm lucky we lived through it!

Winter West, I love the antique canning jars and have a few myself. The glass lid inserts are really cool. Canning is really fun and rewarding. When you store the goods they're so pretty in the jars too. Thanks for your nice comment.

Mckbirdbks - How interesting that you dropped by today. No kidding, I was just wondering how you are. I'll be by to your site a little later. Thanks for your visit.

Pamela99 - I figured you were a fresh vegetable and canning sort, you're so industrious and talented. It's been many years since I put up any vegetables but since I've started gardening again I have a harvest. Thank you so much for your very thoughtful comment and for your visit!

All the best to you,


Pamela Oglesby from Sunny Florida on July 19, 2011:

I used to can a lot for many years and this is a very thorough, well-written hub with great safety tips, as well as, general information. Rated useful and awesome.

mckbirdbks from Emerald Wells, Just off the crossroads,Texas on July 18, 2011:

Hello Peg. I read this with interest and have also bookmarked it. I also, am do not want to poison anyone. This process does offer a way to stretch the tomato harvest. Thanks for the information.

WinterWest on July 18, 2011:

Great hub! I've collected antique Ball jars for years, but I've never worked up the nerve to try canning (with new jars of course). Maybe I'll have to give it a try! Thank you for the information!

Nell Rose from England on July 18, 2011:

Hi, I always wanted to give this a go, but had absolutely no idea how to do it! as you say, you have to be so careful, don't want to poison anyone! thanks, this is bookmarked for future reference, just in case I try it! thanks nell

Food Buzz from Minnetonka, MN on July 18, 2011:

Very useful information, thank you!

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