How to Can Tomatoes to Avoid BPA–Canning 101 for Beginners

Did you keep a garden this summer? Have too many tomatoes on your hands? My favorite part of this time of year is preparing foods from my garden, local farmers, or the surplus from my gardening friends and family. I can the leftover tomatoes to use during the winter. When you garden from your backyard, you know exactly what has gone into the food and can avoid the chemicals the food industry uses to prepare, process and preserve. Most of the food additive chemicals that are approved by the FDA are problematic. In fact, in my book Green Enough: Eat Better, Live Cleaner, Be Happier (All Without Driving Your Family Crazy!) I call the category the FDA uses “Generally Regarded as Safe” (GRAS) the generally regarded as bullshit category instead. Basically, most of the food additives that are put into our food OR that leach into our food from the processing and preserving are more dangerous than they are useful. When we know how our foods are grown, it not only feels good but it allows us to make sure that it is safe for our families. Learning to can tomatoes is not only a good skill to have, but it will protect your family from bisphenols that leach into your food from can linings. Then you can use those same tomatoes all year for sauces and whatever else you would like to prepare and they will be free from bisphenols! You’ve trusted Mamavation to bring you themes like the best and worst store-bought spaghetti sauces, which retail stores have BPA lining their cans & how Americans spend $340 BILLION annually on health care expenses linked to effects of hormone-disrupting chemicals, now join us as we help you learn how to can tomatoes!

Decisions You Need to Make Before Canning Tomatoes

When you’re preparing to preserve tomatoes, you have a few choices to make – will you be using a boiling water canner or a pressure cooker? The nutritional value and quality of the preserved product is typically greater when you use a pressure cooker, but my favorite reason to use mine is that the processing time is not as long! Make my life easier AND give my family the best is a win-win every time! Most people have an Instant Pot, but I have a Bestek pressure cooker, which is less expensive and gets the job done just fine. However, some tomato recipes like salsa need to be done in the boiling water canner, so make sure you check your recipe too.

You also need to consider whether you’ll be doing a raw pack or a hot pack with your tomatoes. I was discussing this with a friend recently because I am not sure that I’ve ever done a raw pack on tomatoes, but I don’t typically preserve whole or halved tomatoes – which can be used in raw pack. Raw pack means that you’re canning the tomatoes without heating them up first. The method that I use is hot pack – this means that the product going into your jar is hot already, and if you’re using a mixture like salsa or spaghetti sauce, or a reduction like tomato sauce, you’ll need to use a hot pack.

That brings me to your next choice – what recipe will you be using? It’s important to know in advance because the format of your canned product can mean that you need to use a different processing time. Finally, you need to decide what size jars you will be using. I could get away with using pizza sauce in pints, but for spaghetti sauce we definitely need quarts in our house!

Additional Important Notes about Canning Tomatoes

Now that you have your decisions made, there are a couple of important items to discuss – what tomatoes to can and adding acid to your tomatoes. When you are canning tomatoes, you need to make sure that the ones you are using are free from disease, were picked from healthy vines, and were not picked from frost-killed vines. Those are the tomatoes you are good to eat fresh, but for the ones that you’ll be saving through the winter, you need to make sure that they’re as awesome as can be. Green tomatoes are also great to can!

It’s now a fairly common recommendation that you add acid to tomatoes – they used to be considered acidic enough to not add acid, but with changes in varieties that people are growing, it is now recommended that you add additional acid to your tomato jars. You can do this by adding organic lemon juice to your jars before you add your tomatoes. The National Center for Home Preservation recommends that you add two teaspoons of lemon juice or 1/4 teaspoon of citric acid to each quart of tomatoes.

And what about bisphenol-A (BPA) in canning lids? Yes, BPA was standard to have inside canning lids, but the industry is trending BPA free. Most companies are providing BPA-Free lids now. However, in order to find out if the lids contain bisphenol-S (BPS), which is an equally problematic chemical in the bisphenol family, you’d have to contact the company. In the meantime, my suggestion would be to leave some extra headspace inside the bottle and make sure to store them right side up. Acid from tomatoes is a chemical that causes leaching, so this is important. But in the grand scheme of things, canning is safer because only the lid poses a problem. It’s not lining the entire can like in canned foods. So this is easier to mitigate if you are storing them properly and allowing extra room in the headspace, which is the space between the liquid and the lid.

Preparing to Can Tomatoes

In your preparation to can tomatoes, you will need a bunch of items and I’ve taken the liberty of linking them up for you so you can browse Amazon for any of the things you are missing. You’ll need the following items:

• Tomatoes prepared according to the recipe you choose
• Boiling water canner or pressure cooker
• Mason jars with lids
• Rings
• Ladle
• Funnel
• Small saucepan for lids
• Jar lifter
• Clean towels

If you don’t have a garden at home, no worries, you can get these tomatoes from a farmers market, but there are some things you’ll need to know. Make sure to ask them if they have flats of tomatoes for canning first. Many farmers will give you a special rate for canning tomatoes. These are the tomatoes that aren’t as pretty and have been picked over by customers, but for canning, that’s not a problem. And if you wait until the END of the farmers market to ask them you are more likely to get a deal. That way, you are doing them a favor and they won’t need to pack it away. Whatever you do, DO NOT go into Whole Foods or a coop and ask them for the most beautiful heirlooms. That will be a big waste of money.

Now planning your kitchen environment for the canning process can be critical, especially if you have a small kitchen with space concerns. Consider what you need to do to fill the jars and complete the canning process (as in, read through ALL the instructions) before you start so that you get an idea of what movements you’ll need to be doing. Canning is a hot, intensive process, and it helps to not stress out if you have it planned out ahead of time!

Find the headspace requirement and processing time that you need for your specific tomato recipe. Not every product will need the same amount of time in the canner or the same amount of distance from the top of your recipe to the top of the jar (headspace). I personally use the Ball Blue Book of canning for reference, but if you don’t have access to that book, I would also recommend checking the website of the National Center for Home Preservation’s tomato section for processing times and headspace requirements.

If you are using a recipe that will be processed for 10 minutes or longer in a pressure cooker, you do not need to sterilize your jars before you can them in either a boiling water canner or pressure cooker, but you may still choose to do so if you would like. Whether you sterilize your jars or not, the first step is always to wash your jars, lids, and bands in hot soapy water. When you’re washing your jars, you need to carefully inspect them to make sure there are no nicks, dings, damage, or weaknesses in the glass. Problems with jars can lead to very dangerous situations in the canning process, so make sure that your jars are all in excellent condition before you continue.

And here are the cooking times based on the altitude you live in.

1,001-3,000 feet, add 5 minutes

3,001-6,000 feet, add 10 minutes

6,001-8,000 feet, add 15 minutes

8,001-10,000 feet, add 20 minutes

How to Can Tomatoes

Now that you have everything prepared, you’re ready to can your tomatoes!

Step 1: Add water to the canner. If you’re using a boiling water canner, the canner should be about 2/3 full of water. You’ll need additional hot water to raise the water level to 1-2 inches above the top of the jars after they’re all loaded. If you’re using a pressure canner, you’ll need 2 inches of water or so, depending on your recipe.

Step 2: Fan our your lids so that they’re not right on top of each other and add them to a small saucepan filled with water and bring to a simmer. Read the directions on your canning lids to make sure they’re the same, but this is the general practice. You do not want them to boil and make sure they are not sticking together.

Step 3: Fill jars with prepared recipe. I use a canning funnel with most tomato recipes because they tend to get a bit sloppy. Place your funnel in your jar and fill! Make sure you leave enough room at the top of the jar (headspace) according to what your recipe says, especially if you are concerned there may be BPA or BPS lining the lid.

Step 4: Remove bubbles. You can do this in a variety of ways, including using a skewer to run down the inside of the jars, wigging the jars on the surface, tapping the jars (gently) on the surface where you’re working, or whatever you’ve found that works. Just make sure you get the air bubbles out!

Step  5: Clean top edge and add lid. Clean off the top of the jar to make sure that there is nothing in the way of the rubber of the lid and the glass of the jar. I use a towel specifically for this purpose and another one for wiping up spills on the side of the jar. Yes, I’m a messy canner! Using a jar lifter (or fork), get one of the lids from the simmer pan and place it on the top of the jar. Do not push it down! Add the band and screw it down tightly.

Step 6: Place jar in canner.

Just repeat steps 3-6 until all your jars are full! Once you’re finished, you can lower the jars into the boiling water canner if you had the basket up. Check the water level in your canner to be sure that it’s appropriate for your recipe and type of canner. If you are using a boiling water canner, you will need to bring the water to boiling – when the bubbles are breaking above the tops of the jars, start timing the processing according to your recipe. If you’re using a pressure canner, you will first need to allow the canner to vent for 10 minutes – start timing venting when you first see steam coming from the vent. After it vents for 10 minutes, add your weight and bring it up to pressure. Carefully monitor the heat beneath the canner to make sure it does not go lower than the pressure desired. If it does, you will need to raise the temperature to get the pressure back up and start your processing time over again. Processing time is only when the pressure is at or slightly above the pressure indicated in your recipe.

These canned tomatoes, if done right, will last anywhere from one to three years if stored in a climate-friendly environment. So make sure you store them in a room that doesn’t get too hot or cold.

Recipes for Canned Tomatoes

Now that you are done canning your tomatoes, what do you do with them? No fear, we’ve reached into the blogger community for you to find some of the best recipes you can use to cook with them. Try some of these recipes out and let us know how it all went in the comment section below.

• Paleo Tomato Soup from The Primal Desire
• Classic Vegetable Soup from Raising Generation Nourished 
• Fresh Tomato Soup from Raising Generation Nourished
• Italian Sausage Stew from Raising Generation Nourished
• Indian Onion Masala from My Heart Beets
• Butter Chicken from Butter Nutrition
• Easy Homemade BBQ Sauce from Oh The Things We’ll Make
• Easy Homemade Fermented Ketchup from Oh The Things We’ll Make
• Easy Homemade Tomato Paste from Oh The Things We’ll Make
• Shakshukah-Mediterranian Breakfast from And Here We Are

For more recipes and tips on how to prepare food and avoid BPA, pick up a copy of Green Enough: Eat Better, Live Cleaner, Be Happier (All Without Driving Your Family Crazy!). You’ll find a ton more recipes on how to prepare beans so you can avoid cans and other recipes that help you avoid hormone-disrupting chemicals in food.