How I Make and Can Tomato Sauce with the Water Bath Method

There are few things more satisfying than opening a jar of tomatoes in the middle of winter, spooning out their rich, sweet flavor, and tasting the sunshine of summer all over again. For me, canning tomatoes has become one of those seasonal rhythms I look forward to every year. It ties together so many things I value—living simply, making use of homegrown resources, and filling our pantry with food I can trust.

Recently, I gathered the last of my ripe tomatoes from the garden. There weren’t as many as I had hoped for, but enough for half a dozen quart jars of tomato sauce.

I used a water bath canner—sometimes called a boiling water canner—for this batch. The water bath method is a safe canning process for high-acid foods, and tomatoes fall right on the line between high-acid and low-acid food. Because of that, the National Center for Home Food Preservation recommends adding extra acidity to every jar in the form of bottled lemon juice or citric acid. This simple step ensures the safe acidity level you need for shelf-stable tomato products.

In this post, I’ll walk you through how I made my tomato sauce—step by step—using the hot-pack method. I’ll include some affiliate links to equipment I use -as an Amazon associate, I may earn a commission from qualifying purchases.

Step 1: Washing and Preparing Tomatoes

Begin with ripe, fresh tomatoes. Any variety of tomatoes works, and blending types—such as roma tomatoes, Cherokee Purple, or other heirlooms—creates a delicious sauce.

Wash tomatoes thoroughly, trimming off blemishes or soft spots.
If your tomatoes are very large, quarter them with a sharp knife. Smaller tomatoes can be left whole.
Place the prepared tomatoes into a large stock pot set over medium heat.
Stir occasionally with a wooden spoon to prevent sticking.

Step 2: Cooking the Tomatoes

Allow the tomatoes to cook until they soften and release their juices. The skins will begin slipping off, and the tomatoes will become soupy.
Once softened, run the tomatoes through a food mill to remove peels and seeds. This leaves you with smooth tomato sauce that is a bit watery.
Return the strained sauce to the pot. Simmer on medium heat, stirring often, until the sauce thickens and is no longer watery.

a pot full of tomato sauce that is still a bit watery

Step 3: Preparing Jars and Canner

Inspect all canning jars, checking for chips or cracks along the rims.
Wash jars in hot soapy water, rinse, and place them in the water bath canner. Heat the canner on high until simmering. Keeping the jars hot prevents breakage when filled with hot sauce.
Make sure the canner has enough water to cover jars with at least 1–2 inches of water. Adjust the water level as needed.
Gather all necessary equipment:
- Screw bands and new lids
- Jar funnel
- Ladle
- Jar lifter
- Headspace measuring tool
  Having everything within reach keeps the canning process efficient.

Step 4: Filling the Jars

Using a jar funnel and ladle, fill hot jars with the hot tomato sauce. Leave ½ inch of headspace at the top of the jar.
Add acidity to ensure safety:
- 2 tablespoons of bottled lemon juice per quart, or
- ½ teaspoon of citric acid per quart.
  (Salt for flavor is optional: add 1 teaspoon per quart if desired.)
Wipe rims clean with a damp paper towel.
Place lids on jars and secure with screw bands until fingertip-tight. Do not overtighten.

a few jars being filled with homemade tomato sauce

Step 5: Processing in the Water Bath Canner

Using a jar lifter, lower the filled jars into the boiling water canner.
The canner should be at a vigorous boil before adding jars. Ensure the jars are covered by at least 1–2 inches of water.
Process quarts for 40 minutes. For pint jars, process for 35 minutes.
- At higher altitudes, adjust the processing time according to guidelines from the National Center for Home Food Preservation.
Maintain a steady boil throughout the processing time.

Step 6: Cooling and Storing

When processing is complete, turn off the heat and let jars rest in the canner for 5 minutes.
Carefully remove jars with a jar lifter and place them on a towel-lined counter. Leave undisturbed for 24 hours.
As the jars cool to room temperature, the lids will “pop” to indicate sealing.
After 24 hours, check seals by pressing the center of each lid. If it does not flex, the seal is good. Any unsealed jars should be refrigerated and used within a week.
Remove screw bands, label jars with the date, and store them in a cool, dry place. Properly sealed home-canned tomatoes should last up to one year.

Why I Love Canning Tomatoes

Every time I line up home-canned tomatoes on my pantry shelf, I feel like I’m tucking away summer sunshine. It’s a rhythm that connects me to the seasons: spring planting, summer harvest and preserving, fall and winter enjoying.

Making my own pasta sauce or simmering a hearty stew in January with a jar of garden-grown tomatoes gives me more than just good food. It gives me memories of time spent outside with my hands in the dirt, of sun-warmed afternoons in the kitchen with a bowl of fresh tomatoes on the table, of the beauty of working slowly with the seasons.

It’s also a way to create beauty every day. A shelf of gleaming jars is beautiful in its own right, but even more so when you know they were filled with your own effort. The canning method is a lot of work—boiling, simmering, filling, wiping, processing—but they are part of a rhythm that grounds me.

And nothing compares to the flavor. Store-bought tomato sauces and canned tomato products can’t compete with the freshness of my own heirloom tomatoes. That’s why this has become one of my favorite things to preserve each summer.

Step-by-Step Instructions (Quick Reference)

For those who need a summary, here’s the quick version of my step-by-step instructions:

Wash tomatoes and trim off bad spots. Quarter large ones.
Place in a large pot on medium heat. Stir to prevent sticking.
Cook until tomatoes are soft and soupy.
Run through a food mill to remove skins and seeds.
Return to pot and simmer until thickened.
Prepare canning jars: wash, heat in water bath canner with enough water to cover.
Ladle sauce into hot jars, leaving ½ inch of headspace.
Add ½ teaspoon of citric acid (or 2 tablespoons of lemon juice) per quart. Add 1 teaspoon of salt if desired.
Wipe rims with damp paper towel. Add lids and screw bands.
Process quarts for 40 minutes in a boiling water bath (adjust for higher altitudes).
Remove jars, cool 24 hours, check seals.
Store sealed jars in a cool, dry place. Refrigerate any unsealed jars.

Final Thoughts

The canning process is hard work, yes, but it rewards you with more than just food. It’s part of a slower, more intentional way of living, one where you work with raw materials, practice home food preservation, and treasure the fruits of your labor.

Next time you see an abundance of tomatoes—whether from your garden or the farmers market—consider setting aside an afternoon for water bath canning. The jars lined up on your shelf will be more than just tomato sauce; they’ll be a reminder of your own hands at work, of your connection to the land, and of the joy that comes from creating something beautiful and nourishing to share with your family.