Preserving the Harvest: Tomatoes

How does a success turn into a failure? One way is that you have a copious harvest and are unprepared for processing it, letting food go to waste, or at best, the compost.

As neglectful as I have been with my tomatoes this summer (I have been extremely busy) they produced quite heavily. In fact, I had one of the best ever crops of large tomatoes, especially from a variety known as “Spring Giant”. This happened even though I didn’t bother to cage them up! So now I have to come up with ways of making sure all that water and soil fertility didn’t just go to waste.

I decided to can my tomatoes and also to can some salsa.To be clear, because the terms are a little confusing, canning in this case means preserving in jars, not in tin cans. Here is a source for canning supplies and books. Canning is awesome for making the most of your crops. We will post a lot more specific and general articles on canning on this website soon.

When canning one must do some research. Some crops are low acid and require greater effort to preserve. Others are highly acidic and need little help. Tomatoes are somewhere in the middle. But they are easy enough. Low acid foods require more extreme canning practices (with the use of a pressure cooker). For our project, we only require a pot of boiling water to preserve.

Canning tomatoes by themselves is easy. The following process is called a “raw pack”.

What you need:


-2 tablespoons of bottled lemon juice per quart of tomatoes preserved (citric acid can be substituted at 1/2 teaspoon to a quart of preserved tomatoes).

-quart jars and lids (brand new, unused)

-large pot of boiling water

  1. Pick nice, ripe tomatoes (not overly ripe, and never use tomatoes that persisted on a dead plant, such as a frost-killed plant).
  2. Wash tomatoes thoroughly and drop them into a boiling pot of water for about 30-45 seconds. Read through this entire process and judge how many tomatoes you should drop into the pot at a time.
  3. Take tomatoes out of boiling water and drop into cold water (you can use ice to intensify the temperature change). Tomatoes will start to lose their skins. Peel all the skins off.

    After being in hot water for 30 seconds, the tomatoes will start peeling. Ice water intensifies the peeling, and makes tomatoes easier to handle.

  4. Place on cutting board (this will get messy so don’t be a ninny). Cut in halves or quarters and squeeze out extra moisture and loose seeds. You don’t have to be terribly thorough about this. Some people skip this step.
  5. Put the results into a strainer and lightly squeeze to get any remaining moisture out.

    Tomatoes should peel easy. If they don’t, but them back into boiling water for a little longer.

  6. Make sure jars and lids have been sterilized. Though they are coming from the factory and are likely sterile anyway, it’s good to play on the safe side. Boil water in large pot and drop lids and jars into the boiling water. Remove them with jar lifter and magnetic lid lifter (these are common items that can be obtained at Ace Hardware or online) and are specifically made for canning.
  7. Lightly pack tomatoes into sterilized jars with appropriate amount of lemon juice or citric acid. Mix as thoroughly as possible, but not vigorously because you want to prevent many bubbles from forming.

    The results, before canning.

  8. Use a rubber spatula to remove any excess bubbles and make sure you have 1/2 inch of head space at the top of the jar.
  9. Apply lid tightly (avoid touching the underside of seal).
  10. Drop jars into boiling water. Pots made specifically for canning have wire racks at bottom of pot for the sake of convenience, but it’s not the end of the world if you lack such equipment. I use a stock pot at home and it works just fine. Boil jars for about an hour and a half (lower elevations will require less time, and higher elevations, more).
  11. Take jars out with jar lifter and set on counter to let cool. You will hear the lids pop, this is the vacuum forming that is part of the preservation process.
  12. Store in a cool, dry place. Use within a year. Longer than a year can pass, but the quality of the tomatoes decrease.

You will notice variations in these instructions online. For one, this is not necessarily an exact science. Much of the recommendations are somewhat overkill, just to be on the safe side. Also the ratio between how much preservative is used to how long you boil jars varies. If you don’t mind using more preservative, you won’t need to keep jars in pots as long. Using more preservative may also increase the lifespan of your tomatoes. However, the quality and flavor is compromised somewhat. It is left to your discretion to judge what is best for you.

Storing tomatoes is cool and all. But I am a southwest kid now, and what I really wanted to make and can is salsa.  So we experimented drawing from several online recipes.

Recipes can make you think you are totally inadequate sometimes because they completely ignore that you aren’t sure how many tomatoes you are going to end up with, and because they are round fruits it’s difficult to know just how much volume you will have. It’s ok. It’s not an exact science, and there are ways around this.

Kitty and The Artful Dodger’s Homemade Salsa

Have ready:

-tomatoes (processed as above, skins removed, most of seeds removed, moisture removed to a reasonable degree).



-salt and pepper (pepper to taste, about tablespoon of salt per quart.

-sugar (about tablespoon per quart)

-jalapeños or other hot peppers

-fresh green onions, cilantro or oregano

-lemon or lime juice

-white distilled vinegar

-some extra dried chili powder like cayenne

-your preferred spices and herbs, which may include cumin, basil, thyme, mexican oregano, etc.  In our opinion, cumin is essential.

  1. Combine tomatoes,  onions and garlic into a blender and make into salsa-like consistency. I use my blender and will do a fine batch, then a chunky batch so I have diversity in texture in the salsa. How much garlic and onion you use is up to you and what you like. I save some more coarsely diced onion to add in the next step.
  2. Take the results and add to a pot, add diced onion and jalapeños or other pepper of your choice. Also add sugar, pepper and salt. If your pot has measurements, you will know about how much you have, so add ingredients appropriately. Try to end up with an amount that ends nicely in quarts. My batch made 5 and a half quarts. That last 1/2 quart of salsa I just put in my fridge for use now. Simmer for about a half hour. During the last five minutes, quickly add chopped cilantro or other freshly chopped herbs or green onions.
  3. Mix in lemon or lime juice and vinegar. I used about 3.5 cups of lime juice for my batch and I added about 1/2 cup of vinegar to be safe.
  4. Pour finished batch of salsa into jar and seal without touching the underside of the seal. Leave about 1/2 head space at top of jar.
  5. Put jars into pot of boiling water and boil jars for 30 minutes.
  6. Let jars cool down on counter (you will hear lids pop). These probably store for about a year, but in my house, they won’t make it through summer. The resulting salsa was friggin’ delicious.

If reading recipes is not your thing, follow this video:

Some books on canning and preserving:

Ball Complete Book of Home Preserving

Keeping The Harvest


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