How to Can Tomatoes

There is nothing like bringing back the memories of summer than by opening a jar of freshly preserved tomatoes on a cold winter’s day. Not only are tomatoes a good source of vitamin a, c, b6, potassium, niacin, and folate, but they taste great! 

Freshly picked tomatoes are available here at Seaway Farms in the late summer and early autumn. Use them for canning of your favourite salsa, chilli, pasta or tomato-based recipes. Enjoy them all year long!  Store them in your pantry or give them as gifts.  No refrigeration needed.

Quick Steps on How to Can Tomatoes.

Before you Start

Home canning requires special equipment like glass jars, metal lids, metal rings, boiling water canners and pressure canners. There are many steps involved in home canning. If you have never done any canning before, it may be a good idea to take a home canning course or read current books and magazines. It is important to follow current, tested best practices for home canning.   Statement above: Canadian Health Guide – General Food Safety Tips

What to look for when purchasing tomatoes for preserving

When choosing tomatoes for canning, always make sure to select disease-free, preferably vine-ripened, firm fruit. Do not can tomatoes from dead or frost-killed vines.

Let’s get Started! 

Step 1 – Roasting Tomatoes

The benefit to roasting tomatoes first, is it increases the flavour and helps speed up the cooking time.

Preheat one to 450 degrees Fahrenheit. Cut tomatoes in half and then place them face down on a high rimmed oven-safe pan.  When the oven is ready, place in the middle of the oven and cook for 30 minutes.  When cooking is finished, drain off the water.  For sauces, or if you prefer not to have the skins left on, you can easily remove the skins at this point. 

Tip: For winter soups and stews, you can skip the roasting process.  Just chop everything up, skins and all, and then crush with a potato masher.  Go to Step 3.

Step 2 – Puree

A blender can be used to puree the roasted tomatoes. If you don’t like the seeds, put the tomatoes through a sieve first.  Add in garlic (optional) at this time based on your taste preferences. 

Step 3 – Cook

Use a slow cooker or pot and cook down to the desired thickness for a particular recipe.  Add in herbs and seasoning for flavour.   Stir occasionally so as not to scorch the bottom of the pot.

Step 4 – Process

To process the tomatoes, you can use an open water bath or a pressure canner.  Using a pressure canner is much faster and can increase the quality of flavour.

This author recommends hot-packing tomatoes and then process them in sterile jars in a pressure canner at 15 pounds pressure for 10 minutes. 

Acidification [1]: To ensure safe acidity in whole, crushed, or juiced tomatoes, add 2 tablespoons of bottled lemon juice or 1/2 teaspoon of citric acid per quart of tomatoes. For pints, use 1 tablespoon bottled lemon juice or 1/4 teaspoon citric acid. Acid can be added directly to the jars before filling with product. Add sugar to offset acid taste, if desired. Four tablespoons of a 5 percent acidity vinegar per quart may be used instead of lemon juice or citric acid. However, vinegar may cause undesirable flavour changes.

[1] USDA Complete Guide to Home Canning