How To Can Fresh Tomatoes at Home Using Boiling Water Bath.


How To Can Tomatoes at Home Using Boiling Water Bath

Tomatoes are one of the first foods many people try to can, partly because canning them is relatively easy.

However, gone are the days when you could smash some raw tomatoes into a canning jar, process them in a boiling water bath for a while, and call it done.

To can modern tomato varieties safely in a boiling water bath (rather than a pressure canner), you need to add some acidity.

Here’s why.

Over the past several decades, many varieties of tomatoes have been bred for sweetness.

Whereas old-fashioned tomatoes had enough natural acidity that you could safely can them without any other ingredients, many of today’s tomato varieties require added acid to bring their pH low enough for boiling water bath canning.

If you do not do this, you will need to process your tomatoes in a pressure canner rather than a boiling water bath (something I do not recommend, because the flavor is not as good).

Per pint jar of tomatoes, add 1 tablespoon of lemon juice or vinegar, or ¼ teaspoon of citric acid.

For quart jars, double those amounts. There is no difference in the taste, but if you’re worried that it might be too sour, you can add a little sugar to offset the added acidity.

If you opt for lemon juice, it’s best to use bottled.

Fresh citrus juice always tastes better.

But in this case, it’s not about flavor, it’s about food safety, and bottled lemon juice has a consistent level of acidity that fresh lemons don’t always have.

You may come across old-time instructions for canning pasta sauces and other tomato-based products that say they may be safely canned in a boiling bath because of the acidity of the tomatoes.

Again, this is no longer considered safe.

For example, plain zucchini is a low-acid vegetable that must be pressure canned.

Adding tomato sauce to zucchini does not increase its acidity enough to make it safe for boiling water bath canning (and if you did add enough acidity from lemon juice, vinegar, or the like, it would taste more like a pickle than a vegetable).

You may, however, pressure such combinations of unpickled vegetables.

Here are four ways to can your fresh tomatoes at home;

#01 The Raw Pack Method

  • The raw pack method involves simply smushing chopped-up raw tomatoes (and added acid, as described above) into clean jars, and then processing them in a boiling water bath.
  • It is certainly the easiest way to can tomatoes, but it is also my least favorite.
  • The disadvantages of the raw pack method are longer processing times and a watery product that tends to separate once it cools in the jars (the red pulp floats unattractively above a layer of almost clear, yellowish liquid).
  • But if you need to get the tomato canning project done in a hurry, raw pack is better than not canning any tomatoes at all.
  • Despite the longer processing time, it is still slightly quicker than the other methods.
  • Be sure to leave at least ½-inch head space between the surface of the food and the rims of the jars.
  • Wipe the jar rims clean before screwing the lids on.
  • Process pint jars of tomatoes in a boiling water bath for 40 minutes, and quarts for 45 minutes.
  • Adjust the canning time if you live at a high altitude.

#02 The Hot Pack Method

  • The hot pack method is almost as easy as the raw pack but results in a less watery product that doesn’t separate as much.
  • Remove the whitish stem ends and cores of the tomatoes and compost or discard them.
  • Chop the tomatoes and put them into a large pot.
  • Bring them to a boil over medium-high heat, stirring.
  • Boil the tomatoes for 5 minutes.
  • Fill clean canning jars with the hot tomatoes, adding acid in the amounts described above, and leaving ½ inch of head space in each jar.
  • Screw on the canning lids.
  • Process in a boiling water bath, 30 minutes for pints, 35 minutes for quarts.
  • Adjust the canning time if you live at a high altitude.

#03 The Hot Pack Blanched-and-Peeled Method

  • This method requires a couple of extra steps, but if you have the time the result is much more colorful and flavorful.
  • Place a large pot of water over high heat.
  • Cut out the stem ends of the tomatoes and compost or discard them.
  • Once the water is at a full boil, drop in the tomatoes.
  • After about 30 seconds, the skins will split and start to curl in a few places.
  • Lift the tomatoes out of the hot water with a slotted spoon and let them drain in a colander.
  • The skins have been loosened by their brief blanching and should be easy to rub or peel off (but don’t worry if you don’t get every single bit).
  • Squish out the tomato seed gel and either discard it or use it to make tomato water.
  • Pack the peeled, seeded tomatoes into clean pint canning jars, pressing down with your clean fingers or the back of a spoon to remove any air bubbles.
  • As you put in the tomatoes, add 1 tablespoon of vinegar or bottled lemon juice to each jar, or ¼ teaspoon of citric acid.
  • Press the tomatoes with your clean fingers or the back of a spoon to remove any air bubbles.
  • Leave ½ inch head space in each jar. Screw on canning lids.
  • Process pints for 30 minutes, and quarts for 35 minutes.
  • Adjust the canning time if you live at a high altitude.


  • Instead of blanching them in water, core the tomatoes and arrange them in a single layer on a baking sheet.
  • Preheat your oven’s broiler.
  • Broil the tomatoes until the skins start to blacken in a few spots (but don’t let them burn all over).
  • This roasting accomplishes the same loosening of the skins that the water blanching does, but also wonderfully intensifies the flavor of the tomatoes.
  • Once the tomatoes are roasted, proceed with the hot pack of blanched-and-peeled tomato canning instructions.


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