7 ways to preserve tomatoes

In this brief guide, we are going to answer the question “7 ways to preserve tomatoes” and discuss 7 ways to preserve tomatoes.

7 ways to preserve tomatoes

The world production of tomatoes has consistently increased since 2000, growing more than 54% from 2000 to 2014. China is the largest producer of tomatoes, followed by the United States and India. Other major players in the tomato market are the European Union and Turkey. Together, these top five tomato producers supply around 70% of the global production (1).

7 common ways to preserve tomatoes are:

  1. Proper room temperature storage
  2. Refrigerating
  3. Freezing
  4. Canning
  5. Dehydrating
  6. Drying and preserving in oil
  7. Making ketchup 

If stored at room temperature, tomatoes must be kept away from direct sunlight. Tomatoes are very susceptible to bruising so they are best stored in a single layer. Raw tomatoes or raw tomato products can be kept refrigerated (below 40 degrees Fahrenheit), but will spoil over time due to bacteria, yeasts, and molds (2).

Unripe, green tomatoes must not be refrigerated or frozen. They must be stored at room temperature until they finish the ripening process. To speed up the ripening process, place the tomatoes in a warm area with light for a couple of days. However, it has been shown that tomatoes ripened on-the-vine have significantly more lycopene and β-carotene content than those ripened off-the-vine (3).

How to preserve tomatoes at room temperature

Properly storing semi-ripe or unripe tomatoes at room temperature preserves them for about 6 months. Both temperature and atmospheric conditions have a direct effect on the fruit metabolism, leading to changes in the formation of flavor compounds. At low temperatures (between 0 and 10 °C), tomatoes can undergo chilling injury with one of the symptoms being a decrease in flavor acceptance (4).

To store tomatoes at room temperature (best at 18-23°C or 64 to 74°F):

  • Line a container or box with newspapers or paper towels. Newspapers or paper towels absorb moisture and prevent spoilage.
  • Place a layer of unwashed, dry tomatoes in the container. 
  • Place newspapers or paper towels on the first layer and then place the second layer. Alternatively, each tomato can be wrapped in newspapers and then placed in a container. However, tomatoes can have deleterious flavor effects were found when O2 levels were lower than 3% and CO2 was 15% or above (4). Therefore, the container should not be closed.
  • Close the container and place it in a cool, dark and dry place.
  • Check on the tomatoes regularly for signs of spoilage.

How to preserve tomatoes by refrigerating

Only ripe tomatoes must be stored in a refrigerator as cool temperatures will halt the ripening process. Refrigerating preserves tomatoes for about one month. Tomatoes stored at low temperature levels may develop chilling injury depending on their exposure time to cold conditions and their maturity stages. For instance, mature green and ripe tomatoes must be stored at 13 to 16°C (55 to 60°F) and at 7 to 10°C (44 to 50°F), respectively (5).

To refrigerate tomatoes:

  • Wash and dry the tomatoes using a paper towel.
  • Cut the stems and slice the tomatoes if needed. Cut tomatoes have shorter shelf life, of 10 days (6).
  • Place the tomatoes in a ziplock bag or an airtight container.
  • Label and place it in the refrigerator.

How to preserve tomatoes by freezing

Tomatoes can be frozen for about a year. Tomatoes can be frozen either whole, halved or sliced (2).

To freeze tomatoes:

  • Wash and dry the tomatoes using a paper towel.
  • Cut the stems and slice the tomatoes if needed.
  • Place the tomatoes in a ziplock bag or an airtight container.
  • Label and place it in the freezer.

How to preserve tomatoes by canning

Tomatoes can be blanched and then canned in a citric acid such as lemon juice. The acidity will lower the pH and preserve the tomatoes for a long time (2). 

Tomatoes can be canned either with or without the skin. Leaving the skin on may sometimes cause a bitter taste.

A drawback with the canning method is that it is time-consuming and requires a pressure canner for the best results. A detailed recipe for canning tomatoes can be found here.

How to preserve tomatoes by dehydrating

Dehydrated tomatoes can be refrigerated for about 618 months (7).

To dehydrate tomatoes (2):

  • Wash and cut the tomatoes in half.
  • Remove the stems. Seeds can either be removed or left as they are.
  • Place the cut tomatoes in a dehydrator tray with the cut side facing upwards.
  • Dehydrate at 57 °C until the tomatoes are dry and leathery in texture.
  • Store the dehydrated tomatoes in an air-tight container. 

How to preserve dried tomatoes in oil

Oven-dried tomatoes can be preserved in oil. This method preserves tomatoes for about 6 months when frozen. Freezing is required since the tomatoes are not completely dehydrated in this method and if not frozen, they may spoil faster.

However, according to the University of Georgia, preserving tomatoes in oil is currently not recommended. Oil may protect botulism organisms trapped in a water droplet. Furthermore, oil may have a deleterious effect on lid gaskets and at least one manufacturer of home canning lids recommends against it (2).

Dried tomatoes in oil are added to pizzas, pasta and sandwiches.

To preserve tomatoes in oil:

  • Wash, cut and scoop out the seeds of the tomatoes.
  • Place the tomatoes on a baking tray and sprinkle with a choice of herbs.
  • Set the oven to the lowest temperature setting and dry the tomatoes overnight in the oven.
  • Once the tomatoes have cooled down, pack them into jars with olive oil leaving 1-inch headspace.
  • Seal, label and freeze the jars.

How to preserve tomatoes by making ketchup 

Tomato ketchup is an integral part of many dishes such as pizzas and pasta, so making ketchup is a great way to preserve extra tomatoes. Homemade tomato ketchup can be frozen for about 6 months or refrigerated for about 3 weeks.

There are several recipes for tomato ketchup. A recipe for slow-cooker tomato ketchup can be found here.

To make tomato ketchup (2):

  • Wash and chop tomatoes. Peel the skin if needed.
  • Cook the tomatoes until they start to fall apart.
  • Puree the tomatoes in a food processor.
  • Add vinegar, salt and sugar and a choice of spices.
  • Cook for about 8 hours.
  • Pout into sterilized jars.
  • Process the jars in a water bath or by using a pressure canner.

Other FAQs about Tomatoes that you may be interested in.

How to store homemade tomato sauce?

Are tomatoes acidic? 

Are canned tomatoes already cooked?

Can you boil tomatoes?

Conclusion

In this brief guide, we answered the question “7 ways to preserve tomatoes” and discussed 7 methods of preserving tomatoes.

If you have any questions or comments, please let us know.

References

  1. Guan, Zhengfei, Trina Biswas, and Feng Wu. The US tomato industry: An overview of production and trade. Universiity of Florida. 2017. 
  2. Andress, E. Resources for Home Preserving Tomatoes. 2018. National Center for Home Food Preservation.
  3. Sorrequieta A, Abriata LA, Boggio SB, Valle EM. Off-the-Vine Ripening of Tomato Fruit Causes Alteration in the Primary Metabolite Composition. Metabolites, 2013, 3,:967-978. 
  4. Boukobza, Fabienne, and Andrew J. Taylor. Effect of postharvest treatment on flavour volatiles of tomatoes. Posthar biol technol, 2002, 25, 321-331.
  5. de Castro, Larissa R., Luís AB Cortez, and Clément Vigneault. Effect of sorting, refrigeration and packaging on tomato shelf life. J Food Agric Environ, 2006, 4, 70.
  6. Antunes, Maria DC, et al. Nutritional quality changes of fresh-cut tomato during shelf life. Food Sci Biotechnol, 2013, 22, 1-8.
  7. Camargo, Gisele A., et al. Shelf life of pretreated dried tomato. Food bioproc technol, 2010, 3, 826-833.