Water Bath Canning Your Harvest
Updated: Oct 25
Welcome to the final installment in our series on preserving your harvest: water bath canning! This is where we can really get creative with jams, jellies, conserves, chutneys, pickles, and more. It is easy to combine fruits and vegetables together, and to add supplementary notes like herbs and spices. The combinations and flavour profiles are absolutely endless. Canned goods will store indefinitely (when stored properly) but will colour and texture may begin to deteriorate after a year. The only downside to water bath canning is that is con be time consuming and take some specialized equipment.
Let's Talk Safety
There is one really important thing to note about water bath canning: it can only be done with high acid foods. High acid means a pH lower than 4.6. This includes most of our fruits and any vegetables preserved in a high acid solution (like vinegar for pickling). Some vegetables, like tomatoes, are on the borderline of being acid enough, so we typically add a bit more acid to ensure safety. It is this acidity that makes water bath canning safe to store at room temperature long term. Really dangerous bacteria like Clostridium botulinum (which causes botulism) will not grow and multiply in high acid environments. In addition, boiling our canning jars at 100°C for a minimum of 10 minutes when using the water bath canning method, kills most other bacteria and fungi, and correctly seals the jars. A good seal is very important, as it prevents anything from getting into the jars and spoiling the contents during storage. Remember, if any of your canned goods do have an off smell, mold, odd colours, or swollen lids, just toss them. Don't take any chances. These are our friends and family we are feeding, after all, and we don't want to take any chances with their health.
Botulism, caused by one of the most harmful food borne bacteria, is completely colourless and tasteless, so we must depend on high acid environments and good hygienic methods to ensure safety.
Any foods that are not high acid, cannot be stored with the water bath canning method. They must be pressured canned using a high-pressure canner. This appliance increases the pressure inside of it, raising the temperature at which water boils from 100°C to 116°C. This is the minimum temperature necessary to destroy botulism spores and the only way to guarantee safe canning when you don't have that high acidity. Note that a high-pressure canner is not a pressure cooker! Your Instantpot is not going to work here. We will not be covering pressure canning today, as it has its own methods and procedures (maybe in a future article). I recommend you look for instructions and recipes specific to your own pressure canner to ensure safe storage. Each brand seems to be a bit different.
Speaking of recipes, it is important to use only modern, recent recipes from reliable resources for water bath canning. I know your grandma's crabapple jelly recipe is the best one ever, but we have made many advances in food science since grandma's day. Remember, the goal is to keep everyone safe and healthy, so please, please use recent recipes! That also means no flip top or clip top jars and no sealing wax. These are no longer considered safe to use as they don't seal our jars properly or reliably. Only use jars specifically for canning and make sure that they have no chips or cracks, and are clean and sterile before use. There is a list of resources at the end of this article with links to safe recipes and equipment.
Alright, now that I have scared you into good safety practices (sorry about that, but it needed to be done), let's get into the fun part: the canning process itself.
Let's start out with the equipment that you will need. You can often find all of tools listed below in a single water bath canning kit available at most hardware stores.
The bigger, the better here. It must be tall enough to accommodate whichever jars you are using plus at least 1" of water overtop of them, plus enough space to allow for rapid boiling of the water. The wider the pot, the more jars you will be able to fit in. There is a trade-off in size, as the larger the pot, the longer it will take for the water to come up to a full boil.
A good metal rack will keep your jars from sitting directly on the bottom of your pot. This will prevent cracks and chips in your jars while boiling and also prevent the food in the bottom of your jars from scorching. If you purchase a canning kit, it will come with a rack that perfectly fits inside your pot. Otherwise, it can be hard to find one that will fit your own personal pot. If you need, you can always place a tea towel in the bottom of the pot instead of using a metal rack.
Getting heavy, boiling hot jars out of rapidly boiling water can be a dangerous operation. This tool will make it so much easier and less dangerous. It will grip the jar right under the screw band and securely hold it while you move them in and out of the pot. Look for one that has a rubber coating for optimal grip, and make sure you are holding the correct end (it can be a bit confusing which end is which sometimes). Trust me, this tool is mandatory.
Funnel and Ladle
Getting your tasty produce into your jars without making a wasteful mess is important. A handy, wide mouthed funnel and ladle will get the job done cleanly and quickly. Plastic is the usual material, as it can be easily sterilized and will not alter flavours like some metals will.
Magnetic Lid Lifter
This handy little tool picks up canning lids from in hot water and allows you to place them on your jars, without you having to touch them (and getting your germs on them).
This is essentially a wide knife shaped tool with little notches in the end that allow you to measure how full your jar is (in reference to the very top of the jar). This is important to know, because every proper water bath canning recipe will give you a headspace measurement to fill your jars to. Why is the correct headspace important? It ensures that your jars seal properly and that they don't explode all over your canner when you process them. So make sure you measure. This tool is also often used to remove air bubbles from jars before processing. Just slide it up and down the sides of the jar a few times.
Jars, Lids, and Screwbands
Only use jars specifically made for canning. These are the same no matter if you are water bath canning or high pressure canning. They are often called mason jars and they come with a flat lid (with a rubber ring imbedded on the underside) and a screwband to attached the lid onto the jar. Jars can be cleaned, re-sterilized and used again. Screwbands just need to be cleaned, as they don't come into contact with our food. However, you must use new lids each time you can to ensure a proper seal; they absolutely cannot be reused. Find jars wherever you can. Garage sales are great options for a cheap supply. You may end up with a motley collection, but you will save money!
Jars come in multiple sizes, from 50mL all the way to 4L, but the most standard sizes are 250mL, 500mL (about 1 pint). and 1L (about 1 quart).
Jars also come with two different sizes of openings (and therefore lids and screwbands too): wide mouth (3.38" or 86mm diametre) and regular mouth (2.75" or 70mm diametre). In Canada, we also have a third opening size that use to be quite popular, but is not longer being made. They are called Gem jars and they are an in-between size of 78mm in diametre. Bernardin still makes lids for these if you do happen to come into possession of some jars.
Lid holder - a simple rack that neatly holds canning lids for submersion in hot water
Labels - Self explanatory. I really like the dissolvable ones.
Candy thermometer - will give you an accurate measure of when your jams and jellies reach the gelling point. There are other methods for determining this as well.
The most important thing is to use fresh, undamaged produce. Hopefully from your own garden, but if you find some good stuff at the farmer's market, go for it! Look for fully ripe produce for maximum sweetness, unless you are using under ripe apples (or other fruit) as a pectin substitute. You can easily add spices, herbs and flavourings as long as they are not in large amounts and do not alter the acidity level. We are following tried and tested recipes for a reason here.
You will notice most jam and jelly recipes contain a lot of sugar. Sugar works with pectin to gel these preserves and also helps retain texture and colour during long term storage. Look for low or no-sugar pectins if you want to reduce the amount of sugar in your preserves. Salt also helps retain texture and colour and you should use pickling salt whenever possible. The minerals found in many other types of salts (like table salt) can turn your produce funny colours. Blue garlic does not appeal to most people! It is however, fully edible, it just looks weird.
Boiling Water Bath Canning Process
Alright, now that we've covered all the basics, let's look at the process, step by step.
Fill canner with water.
ensure a rack or towel is on the bottom so jars don’t crack.
Add clean, empty jars, and bring to a full, rolling boil.
Boil for 10 minutes (plus any elevation adjustments) to sterilize .
if your recipe's processing time is more than 10 minutes, you do not need to sterilize your jars, but they do need to be clean.
they also need to be hot when you add your hot ingredients so they don't crack, so I usually end up boiling them either way.
Once time is up, leave your jars in the pot, reduce the heat and keep warm until needed.
Make recipe, cook produce or boil liquid for raw packing.
do this while your jars are sterilizing.
When you are ready to fill, remove jars form water bath onto a tea towel using your jar lifter.
Add snap lids to water bath to soften the rubber and let them sit in there while you your fill jars.
For raw pack: add fruit or veg to jars (firmly packed) and then fill with hot water, syrup or juice.
For hot pack: add prepared mixture to jars.
Top up until you have exactly the head room space as specified in the recipe (use that ruler to measure).
Poke along sides of the jar to remove any air bubbles.
Wipe rims with a wet cloth.
Place on snap lids and screw bands (just fingertip tight).
Refrigerate any half-full jars. They will not store long term at room temperature safely. Eat these ones first.
Lower full jars into canner, increase heat, and bring back to a rolling boil
remember that filled jars will displace more water than empty jars, so you may need to remove some of your water to prevent overflowing your pot
Once at a full rolling boil, process for time stated in recipe (plus any elevation adjustments).
Remove jars from canner onto a tea towel and allow to fully cool.
you may hear popping sounds as they cool. This is normal! It is the lids being sucked down as the pressure inside the jars decreases with cooling.
Ensure jars are properly sealed.
lids will be sucked in and not move when pressed on
if not sealed after 24 hours, remove mixture from jar, reheat it, re-sterilize jars, refill them, and use new snap lids to seal.
Label and date jars.
Remove screw bands to prevent rust, if desired.
Store jars in a cool, dark place indefinitely, although flavour and texture will be best before 1 year.
A Note About Higher Elevations
Locations that are at higher elevations need to increase their boiling times (for both sterilization and for processing). This is because the higher up you go, the lower the temperature at which water boils. We make up for this lower temperature by boiling for a longer amount of time. Where I live, here in Calgary, we are at an elevation of around 1120m above sea level, so we need to add 5 minutes to all of our boiling times to ensure safety.
For 1,001 - 3,000 feet above sea level, add 5 minutes
For 3,001 - 6,000 feet above sea level, add 10 minutes
For 6,000 or more feet above sea level, add 15 minutes
Raw Pack vs. Hot Pack
There are two main methods for preparing the produce to into your jars. Raw packing (also called cold pack) is when you tightly fill your jars with fresh, unheated produce and then pour hot liquid over top to cover. This liquid can be water, a sugar solution (syrups of varying sugar percentages), or a vinegar solution (for pickling). This method is significantly faster, but there are some disadvantages. You may get more shrinkage with with method, and there is the potential for produce to float in the jars and discolour over time (from the air that becomes trapped around cold food when hot liquid is added). To reduce these effects, ensure you remove air bubbles with a spatula or headspace ruler and opt for higher concentrations of sugar in your syrups. Hot packing involves partially cooking the produce in a liquid and adding the entire mixture to your jars. Jams, conserves, salsas, and relishes are all types of hot packing. This method reduces shrinkage during storage and removes all air from around your food, improving shelf life. It does take longer though. Which method you choose will depend on the produce your are preserving and your own taste preferences. Neither one is right or wrong.
I recently purchased a steam canner and have been experimenting with it. I must say it makes canning much, much faster! The most time consuming part of water bath canning has always been heating up that large volume of water. It always seemed like a waste of water and energy to me. A steam canner, uses just a few cups of water and relies on the steam produced to process your jars. This works because that steam is at the same temperature as boiling water. Here's the big question: is it tested to be safe? The answer is, yes, but not by everyone. For example, the government of Canada has not published anything on the safety of steam canning to date. However, many state universities and extension offices in the United States, have. But not all of them. So please use at your own discretion. So far, I personally am a big fan. The time savings are that significant.
There are a couple things to keep in mind when steam canning though. First off, this method is not approved for sterilization of your jars. Empty jars in a steam canner just don't work well. That means you either need to sterilize them in some other way or ensure you use a recipe with a processing time of at least 10 minutes (then sterilization of your jars is not mandatory). You also still need to adjust your processing times for any high elevations. Steam canners, like high pressure canners that also use steam, need to be kept at a precise pressure. So you will need to adjust your stovetop temperature as you process to keep it at the right pressure (there should be an indicator on the lid to help with this). And a big note: your processing time will start once the correct pressure has been reached, not once the water in the bottom of the boils.
Well, that's it for water bath canning! I hope I have scared you enough that you will always use safe practices when canning, but I also hope you will give it a try. Yes, it takes some time and work, but it is so worth it! There are so many yummy, creative things we can do with this method of preservation!
Yummy gardening everyone!
Bernardin (https://www.bernardin.ca) for all things canning, including safety information and tons of recipes. They have also published many books on canning.
Ball (https://www.ballmasonjars.com) for all thing canning, including safety information, and tons of recipes. They have also published many books on canning.
Healthy Canning (https://www.healthycanning.com) for water bath and pressure canning recipes, tips and tricks.
Home Canning Safely (https://www.canada.ca/en/health-canada/services/general-food-safety-tips/home-canning-safety.html) for everything safety when it comes to home canning.
Food in Jars (https://foodinjars.com) a great blog with lots of safe canning recipes for both water bath canning and pressure canning.
Simply Canning (https://www.simplycanning.com) website with many canning recipes, videos and classes for both water bath canning and pressure canning.
and more to come!