Canning tomatoes: A photo essay

One of our goals for this year's CSA share was to learn some food preservation techniques. We've had success freezing a variety of fruits and vegetables, including strawberries, broccoli, bell peppers, and swiss chard. We've also frozen some prepared foods, like pesto cubes, eggplant slices, and zucchini bread.

Our tomato cabinet

We came home from the farm with eighteen pounds of tomatoes this past Saturday. It was time to try out our new pressure canner. We decided that canning whole tomatoes would be the simplest way to start.

The first step was to clean the canner and lubricate the seal between the canner and the lid. Then we selected and washed the tomatoes, brought a large pot of water to a boil, and washed the jars, lids, and bands.

Following the instructions for the raw pack method, we heated the whole tomatoes in boiling water until the skins split, and then plunged them into a cold water bath. We weren't really sure how long the tomatoes needed to stay in the cold water, though.

Coring tomatoes

As the tomatoes came out of the cold water bath, I removed the cores and skins, cut the tomatoes in half, and began filling the pint jars.

Peeling tomatoes

It was a bit of a messy process, but the skins slipped off the tomatoes easily.

Once all seven pints jars were packed with tomato halves, Jeff removed trapped air from the jar with a spatula and added hot water to each of the jars until there was a half inch headspace at the top. I wiped the tops of the jars clean, positioned the lids, and screwed on the bands.

Loading jars into the canner

Canner full of jars

We added an inch and a half of water to the pressure canner, loaded the jars into it, screwed the lid shut, and heated the canner over a high flame.

Steam escaping the vent

Once steam began to escape the vent, we waited seven minutes. This process is called exhausting. The pressure gauge stays at zero during the exhausting process.

Pressure regulator weight

After seven minutes, I put the pressure regulator weight over the vent. It was set at 10 PSI. Then we waited for the weight to jiggle, indicating that the correct pressure had been reached.

Pressure gauge hovering just over 10 PSI

Once the weight began to jiggle, we set a timer for ten minutes and reduced the heat so that the weight jiggled only one to four times per minute (we averaged about twice per minute). This maintains the proper pressure inside the canner.

Just after taking the lid off the canner

After processing for ten minutes at 10 PSI, we removed the canner from the heat and allowed the pressure to drop to zero. Then we removed the presure regulator weight, waited a bit more, and removed the lid from the canner.

Canned whole tomatoes

We removed the jars from the canner to continue cooling. The raw pack method can cause fruit to rise to the top of the jar, and that is indeed what happened. It doesn't indicate any problem with the canning procedure. But we did notice that there is more air in the jars than when we started, so who knows what that means.

In the end, did our first experiment with canning work? It's a definite maybe.