Beginners guide to water bath canning/bottling

A step by step guide to preserving food using the water bath canning / preserving method. A list of the equipment needed, why it is important and exactly how to do it!

I know, I know, back in the day our grandmothers all just filled up their jars, popped a lid on and called it a day. Nobody died (we hope!) and it was all good.

Well fast forward to today and we now know just a little bit more about how to process food safely to help it store longer and taste better.

Up until a several years ago, I had never even heard of the water bath method of canning or bottling. I did it just like my mum and grandmothers had done it - either using the overflow method or the microwave, which were typical methods for a household preserver in New Zealand. Nothing bad happened, a few jars here and there didn't seal, but no problems - they just went into the fridge.

But then I started reading about the water bath method of preserving and I learnt a few things:

• In America (where they have home canning guidelines, something we don't in New Zealand) the water bath method is the recommended way to preserve jars of food.
• It is totally scientific and based around heating the high acid food in a jar to a specific temperature to ensure that it is safe.
• It adds an extra level of protection and I have found that I have a much higher seal rate using this method.
• It is an extra step but it's not hard and you can use equipment you probably already have

So let's get into it - here is everything you need to know about the water bath canning method

What is the water bath method?

The water bath method is basically processing filled jars of food to be preserved in a large pot full of boiling water, bringing it to a rolling boil and then processing (leaving in the water) for the appropriate number of minutes required before removing from the water and allowing to cool on the bench as the jars seal.

Why do I need to water bath my bottles and jars?

The reason for water bath canning is to heat the contents of the jars to a high enough temperature to kill any bacteria, to seal the jar to make sure nothing can get into the jars and to ensure they can be safely stored at room temperature.

How does it work?

Water bath canning can only be used for high acid foods as the high acid environment is inhospitable to mould, yeast, bacteria and enzymes.

The jar of food to be preserved is placed in the boiling water bath for long enough to heat the contents of the jar to 100°C (212°F) killing any microorganisms that may be in the food. The heat expands the food, pushing out the air that is in the jar. When the jar is removed from the water bath and cools down, it contracts and forms a vacuum seal. This sealed environment keeps out microorganisms that could spoil the food.

What equipment do I need?

• A large stock pot with a lid - the pot needs to be tall enough for the jars to be covered with about 2.5cm of water for processing
• A rack/trivet that fits in the pot - you need something to keep the jars from directly sitting on the bottom of the pot. I have a rack that lifts out (highly recommend!) but when I was getting started, I used a tea towel in the bottom of the pot. It was a bit fiddly but did the job. If you can find a cooling rack that fits in your pot, that would work too, otherwise tie together extra bands/rings from jars that you won't be using and place them in the pot!
• Jar lifting tongs - not essential but they make it a whole lot easier!

Several years ago I splashed out on a Ball water bath canning kit from Kiwi Family Kitchen and I love it! Unfortunately these kits are no longer available. If you are planning on doing a fair bit of preserving, a large stock pot is a great investment but you would need to do some searching to find one.

Another option is to buy a pressure canner - this can be used for pressure canning low acid food (more on this another time) but also as a water bath canner, so if you can't find an appropriate stock pot, this is a great option to look at.

Do all foods need to be processed using a water bath?

Any food that you want to store in the cupboard should be processed using the water bath method. I have preserved jams, chutneys, pickles and fruit for years without using this method and have had very little trouble but I now use it for everything. I have better luck with more jars sealing using this method and I love the guarantee that my jars have been correctly processed and that they are safe for storing and eating.

What foods can't be processed using a water bath?

The water bath method is safe for processing high acid foods - any food that has a pH lower than 4.6. There are some fruits and vegetables that are lower in acid such as tomatoes and these require having citric acid added to the jars to get them to a safe level.

Low acid foods including meat, poultry, seafood and some vegetables can't be preserved using the water bath method, they require a much higher temperature and must be pressure canned.

How do I know which foods are safe to process using a water bath?

Basically, anything that you are preserving using the overflow method is going to be suitable for water bath canning:

• Fruit, such as peaches and fruit juices
• Jams and jellies
• Tomato salsa
• Diced tomatoes (although these are the lower end of the safe pH scale so need citric acid added to them before canning)
• Pickles such as bottled gherkins, relishes and chutneys
• Sauces and pie fillings (as long as they don't contain flour or cornflour as a thickener)

Step by step method for water bath canning

Note: It is important to use a tested recipe when it comes to water bath canning. This is to make sure that the food in the jar has a high enough acidity level to be processed and stored safely. Before starting, read through the recipe and instructions and ensure you follow guidelines for preparation, jar size, preserving method, and processing time.

This is the method that I follow based on information from my Ball Canning book

Step 1. Prepare the water bath

Fill stockpot or water bath canner at least half-full with water. Cover and get it simmering - you will need enough water in the pot to cover the jars by 1 inch once they are in there.

Step 2. Prepare your jars

Check your jars for cracks or breakages as this can prevent sealing or cause the jars to break. Check that you are using new lids/seals and that the rings/bands fit on your jars. Wash everything in hot, soapy water.

Step 3. Sterilise your jars

To sterilise jars you can either run them through the dishwasher on sterilise cycle, heat them in the oven or place them in the water bath for 10 minutes before filling them with food. Keeping the jars hot prevents them from breaking when filled with hot food. Lids and bands can be at room temperature, just make sure they are clean.

If the jars have a processing time of more than 10 minutes, it is actually not necessary to sterilise the jars first, they just need to be clean. Because the jars need to be hot when you are filling them, I still prefer to place them in the water bath until I am ready for them.

Step 4. Prepare the food

Prepare the food for preserving according to the recipe.

Step 5. Fill the jars

Fill one jar at a time with prepared food using a canning funnel (if you have one), making sure to leave head space at the top as recommended in recipe.

Remove any air bubbles from the jar by sliding a clean wooden chopstick or rubber spatula (you want to avoid knives as they can damage the glass) between the jar and food to release trapped air.

Use a clean, damp cloth to clean any spillages from the mouth of the jar.

Place the lid on the jar, apply the ring/band and adjust until fit is fingertip-tight (don't be tempted to screw it on too tight).

Place the jar in the stockpot/canner. Repeat until all jars are filled. Make sure the water covers the jars by at least 1 inch (2.5cm).

Step 6. Process the jars

Place the lid on water bath canner and bring water to a rolling boil. Process for the time stated in the recipe. When the time is up, carefully remove the jars from the pot/canner and set on a clean tea towel on the bench (this is especially important if you have marble or granite bench tops as they can cause the hot jars to crack.) Leave jars undisturbed for 12 to 24 hours and hopefully you will start hearing the "ping" of lids sealing!

Step 7. Check that the jars have sealed

When you press down on the centre of the lid, it should be concave and not flex. Remove the ring/band and try to prise the lid off with your fingers. If the jar has sealed properly, you won't be able to lift the lid.

Wipe down the jars and lids (you don't need to store them with the rings/bands on) label the jars and store in a cool, dark place. Sealed jars will last in the cupboard for years but the quality of the food will start to deteriorate over time. I work on most things being good for a couple of years.

If the jar hasn't sealed in 24 hours, the contents of the jar needs to be either refrigerated and eaten within a couple of weeks or frozen.

Step 8: Label your jars

Don't think that you will just remember what is in the jars! You'll be amazed at how things look similar and if nothing else, it's good to have dates on them so you know which jars to use first.

I like to write the date and the contents of the jar on the lid.

So there it is - a run down of what you need to know before embarking on your water bath canning journey! If you have any further questions, please leave a comment below and also check out the following resources that I have found especially helpful.

Recommended resources:

• The Kiwi Country Homestead Membership
• Food in Jars - website and books
• The All New Ball Book of Canning and Preserving (affiliate link)
• Ball Blue Book of Canning and Preserving
• Kiwi Family Kitchen for preserving equipment in New Zealand

Other FAQ's