In my opinion, there isn’t much better than a fresh, garden ripened tomato on your plate. In fact many of us who grow our own vegetables spend the bulk of our gardening time coddling and caring for our tomato plants. Researching the sweetest, most flavorful varieties, preparing our soil with special nutrients and tonics, pruning and tucking the tomato vines into their cages all summer long just waiting for the first glimpse of red from within the thick green vines. Tomatoes, like most fruits are at their best when they are in season and ripened in the sun. However, the truth is that the tomato is only available this way for a very short season every year. Just like other commonly preserved vegetables and fruits, many recipes have been created to savor the summer flavor of tomatoes all year long.
While a fresh, garden ripened tomato is one of my favorites, one of my least favorite things is an out of season, and warehouse ripened tomato in the middle of winter. Not only do these tomatoes lack flavor but also they often have a mushy, spongy texture that is nothing like its summer version. This is why preserving tomatoes is such a great thing! Imagine making yourself a pot of delicious tomato soup on a cold winter day or spreading fresh crushed tomatoes on a home made pizza in February. Not many things can bring back the warm memories of summer like the taste of a great tomato.
Preserving tomatoes is easy. They are mostly considered a high-acid food and can be canned using the water bath canning method when acid is added. To get the quickest fresh summer flavor later, try canning your own tomato sauce, whole or crushed tomatoes.
Tomato specific preserving tips
Fruit - Choose only firm, ripe, disease free fruits. Never use tomatoes from dead or frost damaged vines which will destroy their acidity. Plum, paste or dry-farmed varieties of tomatoes will produce a more concentrated tomato flavor product with less pre-cooking.
Acidity - This is the most important factor in any home canning project, but is mostly a non-issue with pickles and jams because there is so much acid in those recipes to begin with. Tomatoes straddle the line in between high and low acid and have a high natural water content so you have to be extra careful to maintain an acidic enough environment to can them safely. Modern tomato canning recipes will call for bottled lemon juice or citric acid. It is very important to follow these recipes and add the proper amount of either.
Processing times - The processing time is the amount of time the jar is submerged under boiling water after they have been packed with food and the lids has been put on. Processing your jars ensures that all of the ingredients have been brought up to temperature, killing molds and yeasts and facilitating a proper seal of your lids. Tomatoes require a longer processing time than other high-acid foods because of their structure and water content. Certain “spoilers” can survive a shorter processing time and if they proliferate, can de-acidify your product to an unsafe level.
The USDA recommends the following processing times for tomatoes:
- tomato juice, hot pack: 35 minutes for pints, 40 minutes for quarts
- crushed tomatoes, hot pack: 35 minutes for pints, 45 minutes for quarts
- tomato sauce, hot pack: 35 minutes for pints, 40 minutes for quarts
- ketchup, hot pack: 15 minutes for pints, 20 minutes for quarts
Troubleshooting Tomatoes
Watery sauce or separation – The natural pectin in your tomatoes is what allows the sauce to thicken during cooking. Tomatoes contain an enzyme that when exposed to air begins to degrade their natural pectin. This can cause your jars of sauce to separate into layers of sauce and water. Working in small batches and choosing fresh tomatoes will help avoid this issue. Cooking your tomatoes with the skins and seeds will allow the tomato to release more of its natural pectin which will also help with this issue. Separation is just a visual problem, just shake your jar of sauce before you pour it and you will be A-OK.
Floating tomatoes – When canning whole tomatoes, a common complaint is a large amount of liquid at the bottom of your jar with “floating tomatoes” at the top after processing. The floating is caused by the tomatoes natural water content being released after you process them. First off, other than a visual disappointment to the person who labored over each jar, this is creates no issue with your final product. While you cannot avoid floating tomatoes all together, pouring out some of the juices as you pack your jars can reduce this problem. Also, choosing fresh, firm tomatoes to start with can help with floating issues. Packing tomatoes in a regular mouth jar is another solution. The opening of the jar is smaller so the tomatoes are naturally pushed downward. Want to eliminate this issue? Crush or quarter your tomatoes before packing. They most likely will end up in that state when you open and use the tomatoes later.
Removing seeds and skins - When making a puree or paste, cook down the tomatoes with their skins, seeds and cores before running them through the food mill. This allows the pectin to be released during cooking and will save time.
Getting Started -
This recipe and guide is for 7 pints of tomato sauce using the “hot pack” canning method. Hot pack is when you place hot food into hot jars.
What you will need:
Equipment
- Canning pot with rack
jar lifter
lid lifter and bubble remover
canning funnel
new canning lids
clean canning jars
a non-reactive cooking vessel
a food mill
Ingredients
- 22 pounds tomatoes
Bottled lemon juice
2 tbs. Salt (optional)
Prepare your equipment
Fill your canner 2/3 full of water and start heating it up.
Select the number of jars you will need based on your recipe. Select jars free of cracks, defects or chips. Wash the jars, lids and bands and all of your tools in hot, soapy water. Sterilize your jars by placing them in the hot canning water for 10 minutes.
To sterilize your jars properly, you must have the water above 185° F. Leave your jars in the hot canning water until you are ready to fill them so they remain sterile and hot. Place your canning jar lids in a small saucepan and heat it to 180° F for 10 minutes. DO NOT BOIL your lids.
Always follow a recipe when canning anything. If you stray from your recipe, you risk spoiling your food or ending up with an undesirable taste profile.
TIP: If you are not familiar with the water bath canning method, read our blog on the subject or watch our short Learn Em’ Video before attempting this recipe. And as always, make sure you are following all safety guidelines outlined by the USDA when canning anything.
Make your sauce
Clean and slice your tomatoes into quarters. Place the tomatoes in your non-reactive pot and cook on medium low for 20-30 minutes stirring occasionally to avoid burning your sauce on the bottom of the pan. Your tomatoes will get softer and release much of their liquid. Turn off the heat and scoop your tomatoes and the cooking liquid a large spoonful at a time into your food mill. Processing your tomatoes through the food mill will puree the tomatoes and remove the skins and seeds all at the same time. You could pulse the tomatoes in a food processor but large bits of skin and all of the seeds would be incorporated into your final sauce and both will give it a bitter taste and undesirable texture.
Now that you have your strained pulp, transfer it back to your cooking pot and cook over medium-high heat, uncovered. Let your sauce cook until it has thickened and reduced by one-half. Make sure not to wander off. You will need to be stirring the sauce often.
Remove your sterilized jars with your jar lifter from the canner and place them on a clean kitchen towel. Add 1/2 tablespoon of bottled lemon 
juice to each pint jar. Ladle your hot sauce into each jar leaving 1/2-inch of head space (the measurement of space between the lip of the jar to the top of the food or liquid). Run your bubble remover around the inside of the jar to remove any air bubbles from the sauce. Place clean lids and rings on your jars and hand tighten them. Now it’s time to process! This recipe calls for a 35 minute processing time in a water bath canner. Again, if you are not familiar with the water bath canning method, read our blog on the subject or watch our short Learn Em’ Video before attempting this recipe. And as always, make sure you are following all safety guidelines outlined by the USDA when canning anything.
