Tomato-based sauces are immensely satisfying projects that can be homegrown and homemade from start to finish. The beginnings of my first batch of pizza sauce started with 18 tomato plants we’d planted.
Paste tomatoes are the best option for creating sauces, since they have more “meat” and less liquid. That said, you can use any tomatoes if you have the patience to cook the puréed tomatoes down to sufficient thickness. I ended up using non-paste tomatoes, and here’s what happened.
Ripening Tomatoes
Most tomatoes won’t fully ripen before the first frost in our short-season northern climate. Each fall, right before the first frost kills the garden, we harvest every green tomato we can pluck off the plants. We take them indoors, lay them in an enclosed box, drop in a couple of bananas or apples, and enjoy ripe red tomatoes for two months. (Bananas and apples are abundant natural sources of the fruit-ripening gas ethylene.) As an extra precaution, we often drape netting over the box to keep fruit flies away.
As the tomatoes ripen, we collect them and run them through a food strainer to remove seeds and skin. We bag the resulting tomato purée in 1-gallon bags and freeze them. When deep winter comes, it’s time to turn this summer bounty into tomato sauce, including pizza sauce.
As a rule of thumb, it takes about 6-1/2 pounds of tomatoes to produce a quart of finished pizza tomato sauce. Use this to estimate how many tomatoes you’ll need and how much finished product will result from your harvest.
Cook Down the Tomatoes

Fresh (or frozen) tomato purée from non-paste tomatoes is runny and watery, unsuited for much of anything. But cooked down? Ah, that’s another story.
Cooking down tomato purée is simply applying low heat for a long time. I prefer to wait until our wood cookstove is in constant use during the cold winter months. Others use the stovetop at low heat, a slow cooker, or an oven. All of these options aim to reduce the water content of the purée until the liquid thickens into something that can be used as a base for everything from soup to paste.
In our case, I start by defrosting some of the bags of frozen purée overnight in a bowl. By allowing the purée to defrost overnight, some liquid escapes from the bag (leaving the more solid portions inside), which means less to cook down.

After this, I nest two large pots together in a double-boiler style. A double boiler keeps the sauce from scorching and is infinitely preferable to cooking the purée over direct heat. However, it’s important to monitor the larger pot’s water level to ensure it doesn’t boil dry.
While cooking purée down to sauce is a slow process, it’s almost maintenance-free. All I have to do is make sure the lower pot doesn’t boil dry and give the sauce the occasional stir. That’s it.
The first time I cooked down tomato purée, I despaired of ever turning this watery gloop into sauce. It seemed to take forever (three days, in fact). I wondered if I was wasting time.
And then something magical happened: It cooked down into the most beautiful smooth tomato sauce. I couldn’t believe it.
At this stage, tomato sauce can be “specialized” by flavoring it. (Mexican? Italian? Middle Eastern? Russian?) I prefer to keep my sauce unflavored, which means I can flavor it however I want down the line. After adding an acidifier, I can most of my tomato sauce in pint jars in a water bath.
Pizza Sauce Process
I reserve some for making pizza sauce, which means it must be cooked down even further, to a consistency between sauce and paste. Once this process is complete, the bare pizza sauce can be flavored. Pizza sauce is infinitely versatile, depending on one’s taste. You can add spices (black pepper, garlic powder, crushed red peppers, basil, oregano, etc.) or vegetables (onions, bell peppers, hot peppers, mushrooms, zucchini, artichoke hearts, etc.). However, how you flavor the pizza sauce will determine whether it should be water bath canned or pressure canned. For safety reasons, when you are learning how to can, always follow approved recipes exactly. Recipes will specify if the sauce must be pressure canned or if you can safely water bath can it. You can learn more from the National Center for Home Food Preservation.
If the sauce is purely tomatoes with no additions except herbs, it can be water bath canned (along with an acidifier; more on that below). If you add low-acid ingredients, such as mushrooms, onions, bell peppers, or other foods, then the sauce must be pressure canned. No exceptions.

Proper Acidity
Note on acidifiers: When canning any tomato product, adding an acidifier is necessary. Modern tomato varieties – even heirloom varieties – are often on the razor-thin safety borderline for pH levels for water bath canning, hence the need for an acidifier. To quote Penn State Extension, “Tomatoes are on the cusp of what food scientists would consider to be ‘acidic’ foods, and failing to adequately increase the acidity can result in deadly botulism poisoning. To assure safe acidity in whole, crushed, or juiced tomatoes, add two tablespoons of bottled lemon juice per quart of tomatoes or one tablespoon per pint. Only use bottled lemon juice because the acidity level is constant.” The U.S. Department of Agriculture (USDA) also recommends adding acidifiers, even to pressure canned tomato products. Check out the USDA Complete Guide to Home Canning for further safety guidelines.
Most people prefer using lemon juice or citric acid as an acidifier since vinegar may alter the product’s flavor. Remember, all canning recipes for tomato-based products are based on acidified tomatoes. A touch of sugar can offset any bitterness resulting from acidifiers.
Canning Homemade Tomato Sauce
As a rule of thumb, 1 pint of pizza sauce is usually enough to cover two 14-inch pizzas. If you make one pizza at a time, can the sauce in half-pint jars so the extra sauce doesn’t go to waste.
To water bath can pizza sauce, make sure the sauce is hot. Add your desired spices. Ladle the hot pizza sauce into pint or half-pint jars. To each jar, add the required amount of acidifier. Take a minute to double check your elevation if you don’t know it exactly. You may need to add extra time to your processing.
Can Sauce with Low-Acid Ingredients
As stated previously, if your pizza sauce contains any low-acid ingredients, it must be pressure canned. The rule of thumb is to process a food product in accordance with the ingredient requiring the longest processing time. It’s essential to have an up-to-date USDA-approved canning reference guide to know the proper processing times for each food.
If you’re unsure about the proper amount of time to process pizza sauce with low-acid ingredients in a pressure canner, the safest option would be to add fresh low-acid ingredients to the pizza during the pizza-making process, rather than worrying about canning those ingredients with the pizza sauce.
Homemade pizza is far cheaper than frozen or restaurant pizza and can be customized precisely to taste. I haven’t yet found a restaurant pizza – much less a frozen one – that beats homemade.

And it’s made all the better by home-canned pizza sauce, a great method of using up garden tomatoes, especially those paste tomatoes. Having jars of pizza sauce in the pantry, ready to use, means homemade pizza is that much easier to make. If the basil, oregano, and garlic powder are similarly homegrown, you’ll have the additional satisfaction of knowing your pizza is a product you created from start to finish.
Patrice Lewis is a wife, mother, homesteader, homeschooler, author, blogger, columnist, and speaker. An advocate of simple living and self-sufficiency, she has practiced and written about self-reliance and preparedness for almost 30 years. She’s experienced in homestead animal husbandry and small-scale dairy production, food preservation and canning, country relocation, home-based businesses, homeschooling, personal money management, and food self-sufficiency.