Homemade Tomato Paste | Conserva di Pomodori

In Calabria, even today, conserva is dried under the hot Mediterranean sun. Spread on a big wooden slab and brought inside at night, tomato purée dries to a thick paste in three to four days. When my grandmother was young, she and her neighbors around Verbicaro never put up whole tomatoes or tomato purée. Instead, making conserva was the way they preserved their tomato harvest for the winter. Most Calabrians keep their conserva in crocks in the pantry, sealed with olive oil.

In my grandmother’s day, people used conserva for their winter tomato sauce. They would sauté some garlic, then add a few tablespoons of conserva and some water and simmer until the conserva dissolved. Today, most cooks use conserva to add depth to sauces made with canned tomatoes or to ragù.

Like many time-consuming kitchen arts, making conserva is not as common as it used to be. When my mother was young, every rural housewife made time for it. Although you can still see the big trays with their brick-red topping in rural Calabria, and sometimes on suburban balconies, many people have given up making it. When you do find it for sale, it is priced like gold.

Homemade conserva has a deep, mellow, caramelized flavor wholly unlike the acidic taste of canned tomato paste. I dole out this precious preserve by the teaspoon to add depth to braised lamb shanks or goat sugo. Often, after tasting these conserva-enriched dishes, guests ask me, “Why is this so good?”

Use only fully ripe, fragrant summer tomatoes for conserva, preferably from a farmers’ market or home garden. It is not worth going to the trouble of making it with standard supermarket tomatoes. I use the San Marzano tomatoes my father grows, but you can use any type of ripe plum tomato or salad tomato.

When using conserva, always salt the dish after you have added the conserva, as the paste is quite salty.–Rosetta Costantino

LC What She Said Note

Yeah. What she said.

Special Equipment: 1-pint canning jar

Homemade Tomato Paste Recipe

  • Quick Glance
  • 50 M
  • 6 H
  • Makes about 1 pint

Ingredients

  • 10 pounds very ripe plum or salad tomatoes
  • 1/4 cup kosher salt
  • 1 tablespoon extra-virgin olive oil for the baking sheet, plus more for topping off the jar

Directions

  • 1. Core the tomatoes. If they are the plum type, cut them in half lengthwise; if they are the large, round salad type, cut them in quarters. Remove the seeds with your fingers. Place all the tomatoes in an 8-quart stainless steel pot and bring to a boil, stirring occasionally until the tomatoes release their juice. Boil briskly for 30 minutes to soften the tomatoes and reduce the juice.
  • 2. Pass the tomatoes through a food mill fitted with a fine disk to remove the skins and any remaining seeds. Return the tomato purée to the same pot and set over high heat. Stir in the salt, reduce the heat to mediumish, and simmer until the purée has reduced to about 1 quart (4 cups), 45 to 55 minutes. Turn the heat down as the purée thickens to prevent it from bubbling and splattering furiously, and stir often to prevent scorching.
  • 3. Lightly oil a 12-by-17-inch rimmed nonaluminum baking sheet. With a rubber spatula, spread the thick tomato purée in an even layer. It should cover the slicked baking sheet.
  • 4. Preheat the oven to 200ºF (93ºC) and turn on the convection fan if you have one. Position a rack in the center.
  • 5. Place the baking sheet in the oven and bake for 30 minutes. Remove from the heat (keep the oven on) and stir the purée with the rubber spatula so that it dries evenly and doesn’t form a crust. Re-spread the purée with the spatula into a rectangle about 1/8 inch thick. Be fanatical about spreading it evenly; if any part is too thin, it may burn. Because of evaporation, the purée will no longer cover the baking sheet. With a paper towel, remove any bits of tomato that cling to the edges or exposed bottom of the baking sheet, or they will burn.
  • 6. Return the baking sheet to the oven and continue baking until the tomato purée is no longer saucelike but very thick, stiff, and a little sticky, about 3 more hours total. Every 20 minutes, stir and carefully re-spread the purée as before. The rectangle will become progressively smaller as the remaining water evaporates.
  • 7. Let the tomato paste cool to room temperature, then pack it tightly in a clean jar with a spoon, tamping it down to make sure there are no air pockets. Level the surface with the back of the spoon. Cover the surface completely with olive oil so that the paste is not exposed. Screw the lid on the jar and refrigerate. After every use, level the surface of the paste and top with more oil so the paste remains completely submerged. It will keep in the refrigerator for at least a year.

Sun-Dried Tomato Paste Variation

  • If you know you will have 3 to 4 consecutive days of 100ºF (38ºC) weather, you can dry the tomato purée under the sun instead of in the convection oven. Follow the recipe in every other respect, and start to use the sun at step 4. Be sure to bring the tray in at night so it doesn’t get damp.
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Testers Choice

Testers Choice
Testers Choice
Helen Doberstein

Aug 27, 2013

Finally, something new to do with summer’s bounty of tomatoes. The instructions look daunting, but it’s simplicity itself to make, providing you set aside the time. As it was too early for my tomatoes when I tested this recipe, I cut a deal with the local farmers’ market for overripe tomatoes. Coring and seeding the tomatoes was a simple matter, as was cooking them down until the juice was released. I did find it odd that the instructions had us put the tomatoes through a food mill or sieve to remove the seeds when I’d removed them already. I think a food mill was the best choice to remove the skins from the cooked tomatoes, as it did a bang-up job providing me with a smooth purée with nothing extra in it. I used a slotted spoon to remove the tomatoes from the pot to avoid excess liquid going through the mill. The recipe didn’t specify whether or not to add the excess juice back to cook down with the purée, so I left most of it in. I let it cook down for a full hour because it was so runny. The timing was spot-on, baking it low and slow with no burning. For all that work, I got three 125-milliliter jars of tomato conserva. They’re not kidding when they say it’s salty. I’ll definitely be making this again when tomato season is here, but I might cut down on the salt a little, as 1 heaping teaspoon paste seasoned an entire large pot of lamb ragu such that I didn’t need to use any additional salt. I can’t wait to use this in more dishes.

Testers Choice
Linda Pacchiano

Aug 27, 2013

It’s time-consuming but very satisfying to make your own tomato paste, and so much better than store-bought! Now I know why my Calabrese grandmother took the time to do this, even though she single-handedly raised seven children who each had different food preferences and each received a personalized meal every evening. She never really left her kitchen except to sleep or garden or tend the chickens, so I guess she didn’t mind the time it took to make her tomato paste from scratch. Of course, she dried her purée under the sun, never in the oven as I did. And she used her own homegrown Jersey tomatoes, which are full of flavor and taste like actual tomatoes. I was fortunate enough to have a few pounds left in my freezer from my harvest last season, and so I used them, prorating the recipe based on the quantity of tomatoes I had on hand, which was about 3 pounds. This produced a fairly small amount of paste, but at least I was able to experience the process and know I can be successful with larger amounts in the future. The only suggestion I have is to use an offset spatula when spreading and respreading the paste on the baking sheet. This tool will give you a nice even layer, just like spreading icing on a cake, which is important for the paste to develop evenly in the oven.

Testers Choice
Jo Ann Brown

Aug 27, 2013

Every year come late summer, a delivery truck would arrive at our neighbor’s and bushel after bushel of Roma tomatoes would be unloaded and carried down the narrow urban driveway into their backyard. A peek between the webbing of our rear fence revealed a stunning sea of shiny, plump red jewels nestled in straw-colored wooden-slat baskets arranged in neat rows at their basement kitchen door. This is where Signora Catania’s annual canning assembly line began. In her cool, dark basement with the red custom terrazzo floor were oversized kettles and tools, most of which I’d never seen in my own mother’s kitchen. I’d ask my mother, “Why do they need so many tomatoes?” She answered that they were “putting up the sauce.” Not until I was older did I understand that she was preserving the fleeting fruit for use during winter when no self-respecting Italian homemaker would use the pink, mealy hothouse tomatoes that came in cellophane-wrapped green plastic baskets. I now practice my own scaled-down version of the preservation ritual, but it never occurred to me, being an apartment dweller and all, that perhaps making conserva di pomodori would be more efficient and versatile given my limited storage space. This recipe sparked a new approach in my household. Since this was an experiment, I halved the recipe and used the best plum tomatoes I could find at the market. To speed production, I used an apple corer to spear the tomatoes, deftly removing the stems and cores in neat cylinders. The times were accurate, even for half the recipe. I used a 1/4 sheet pan (9 by 13 inches) rather than a 12-by-17-inch one and evaporated the purée on a rack in the bottom third of the oven. After it was cooled, the final product fit in a sterilized half-pint Ball jar. This is the perfect amount for me to use until late summer ushers in the stars of the crops. The final conserva is indeed salty, but it has a wonderful rich, sweet, and complex tomato flavor when compared to store-bought versions of tomato paste. I love learning new techniques and this is a very valuable recipe when endeavoring to preserve summertime.


Comments
Comments
  1. Amy says:

    OY!!!!!!!! You know, I know a Rose Constantino in Farmington………..

  2. Ecoteri says:

    Do you think it could be put into a dehydrator for the last bit rather than in an oven? Thinking of simplifying the reduction process…closer to the temp of air-dried?

    • Renee Schettler Rossi says:

      Terrific idea, Ecoteri. I absolutely think it can be finished in a dehydrator, although since we didn’t test it that way, I’m afraid I can’t offer you specific guidance regarding the exact setting and timing required, although if, like me, you’ve ever just thrown something in the dehydrator and kept an eye on it, I’m certain you’ll be fine. Love to hear what you think and how long it took….

    • Dave says:

      I know this can be put into a dehydrator, as that is how I prefer to make it. The taste is different, and some might prefer this taste, as some might prefer that of the sun. The taste of cooked tomatoes is more familiar, but I personally don’t like cooked as much. Cooking robs aromatics.

      We have two Nesco American Harvest FD-61 dehydrators and extra trays and fruit roll inserts for all trays, making two stacks of eight, which can handle nearly 30 lbs of tomatoes at a time. Our primary conserve (not estratto) is a 4x reduction, made by skinning, salting, chunking and putting on lightly oiled fruit roll trays to dry till “gooshy” then package to freeze. We haven’t opened a can of tomatoes in 10 years.

      I’ve made various conserva/estratto experiments. Cooking and passing the tomatoes through a food mill starts out very wet, and the fruit roll trays handle perhaps 1/2 cup of liquid. Instead proceed exactly as above with peeled chunks, but to a 3x reduction, and then pass through a food mill and dehydrate some more. The dehydrator on high cooks just fine, while robbing less flavor than a simmering pot, more like the sun. And one handles a much bigger load this way, essential because Sicilian estratto is a 10x to 16x reduction.

      Rosetta’s book also gives weights; she calls for 35g salt for 4500g tomatoes, or about 0.7% salt by weight. Other recipes I know go up to 1.5%.

      • Renee Schettler Rossi says:

        Dave, I’m at a loss for words except to say many, many thanks for sharing your experience and insights. I so appreciate it. Many, many readers will benefit from this. Again, thank you. Looking forward to hearing which recipe on the site you tackle next…

  3. Rebecca says:

    A few weeks ago I made tomato paste much like this using my crock pot with the lid off instead of the oven. It took 2 days to cook down from completely full to about 2 cups final product. I had it on low heat for the first day and upped it to high on day two. Stirred every 45 to 60 minutes with a silicone spatula. I also didn’t salt mine until almost finished. This is the best tomato paste in the world.

    • Renee Schettler Rossi says:

      Brilliant, Rebecca! Simply brilliant. (If anyone happens to try this tomato paste recipe in a slow cooker following Rebecca’s notes, we’d love to know if it follows the same timing.) Many thanks for sharing such a swell tactic!

    • Beth Price says:

      Love anything that can be done in a slow cooker! Thanks for the inspired technique.

  4. Donna Turner says:

    This is a very precious post. I never had any idea…I was an idiot. Now I am not so stupid. Thank you so much.

  5. minervaowl says:

    I think that a tomato paste recipe is the last one I need to get completely away from store-bought canned tomato products, so I am excited to try this recipe. I have a couple of questions though. I am not sure whether any of my baking sheets are non-aluminum. Would a large Pyrex dish be an acceptable substitute? Also, how important is it to remove the skins? Do they affect the flavor significantly? I leave skins on when I can tomatoes and when I make sauce.

    • Renee Schettler Rossi says:

      minervaowl, that’s swell to hear on completely veering away from store-bought canned tomato products! Can’t wait to hear what you think of this recipe. As for the baking sheet substitution, I worry that the high sides of a Pyrex dish will impede evaporation of moisture and either prolong the drying process or perhaps even sabotage it. What if you used your baking sheets and covered them with several thicknesses of parchment paper and then oiled the paper? That way you get the advantage of the low sides yet don’t have to worry about whether the surface of the sheets are aluminum and, thus, reactive with the acid in the tomatoes? As for the skins, you know, I guess it’s more personal preference than anything. The taste may be slightly more tannic with the skins on, but really the difference is going to be in the texture of the resulting paste. Suit yourself. And do let us know how it goes!

      • minervaowl says:

        Parchment paper! I love parchment paper! My cookies practically leap off the baking sheet now that I use parchment paper. I’ll try that option if I don’t decide to go with the crock pot, which is very tempting so that I don’t have to worry about even spreading. Thanks.

        • Renee Schettler Rossi says:

          Either way, minervaowl, we wanna hear what you think! And you’re very welcome.

  6. Annerieke says:

    As I live in Palestine and there is plenty of heat and sun here, could I skip everything past step 3 and just dry it for 3 to 4 days in the sun on my balcony?

    • Renee Schettler Rossi says:

      Annerieke, we haven’t tested this recipe using that method because it’s too humid here, but I dare say yes, you can, seeing as that’s how they did it back in the day. Good luck! I’m sure it will work fine. And I’d love to hear how long it takes to dry….

  7. Lauralee Hensley says:

    Thanks. I think I’ll try it in the food dehydrator, except I’ll have to get the fruit roll up puree trays that can be used in the dehydrator. I never bought those, only have the screens for the layering in the food dehydrator. I think this would be much like drying it in the sun. Maybe not though. I’ll have to go to the farmers market after I see if I can get the trays.

    • Renee Schettler Rossi says:

      We have those trays for our dehydrator, Lauralee, and they actually come in quite handy….

  8. I love the colour of this. Just makes me want to take a big spoon and swipe some off the side. I hate using canned paste so I’ll have to give this a whirl.

    • Renee Schettler Rossi says:

      Lovely, Cravings! We’re looking forward to hearing what you think of it when you make it….

  9. Is the salt essential? Does it aid in the preservation, or would this work with straight-up tomatoes topped with olive oil in the fridge?

    • Beth Price says:

      Hi CC, the salt adds flavor but more importantly it attracts moisture from the tomatoes to add in the preservation process.

      • minervasowl says:

        I made my batch a couple of months ago, and while I lost patience waiting for it to become a truly thick paste, I am pleased with it overall.

        Re: the salt — the intensity of the salty flavor has mellowed with time. I’m not quite ready to just sit down with a jar of tomato paste and a spoon, but the salt flavor is definitely not as sharp as when I first made it.

        The type of salt you use can make a big difference as well. Industrially manufactured salt (even kosher) will have a sharper, more astringent flavor than, say, relatively small batch, solar evaporated Fleur de Sel. (I used to think salt was salt until I read a book about it. While it has made me a bit of a snob about salt, it has also opened a whole new world of taste and flavor possibilities, especially when it comes to tomatoes, which *love* salt and take on a more complex flavor profile with even a light dusting.)

        • Beth Price says:

          Yes, Minervasowl, the salt does make a world of difference. Which type of salt did you use for your batch?

          • minervasowl says:

            I used the “house” Fleur de Sel from the Meadow (there is a shop in Portland, OR, and one in NYC) which has become my everyday salt. The shop owner is the author of the book I read. It’s expensive (compared to grocery store salt), but given how long the bag has lasted, despite using some significant quantities for a couple of preserving recipes, I have definitely gotten my money’s worth.

  10. Rita Jackson says:

    I used my slow cooker, it took three days here in our damp maritime climate. My organic Roma tomatoes reduced down to one ice cube tray of tomato paste cubes. Had to freeze then put into a Ziploc bag. I used one cube in my pasta sauce…divine!!

    • Renee Schettler Rossi says:

      Love that you sorta innovated given your climate, Rita. And love that you love this paste. Thanks so much for taking the time to let us know….

  11. Laura says:

    I’m obsessed with ketchups and tomato paste this season. Mostly following your method if not your recipe (yet:).

    Not using the cookie sheets because I would need to buy a new one that is stainless steel before I’d put tomatoes on it. I did use a large ceramic casserole (10×14) which I poured the cooked sieved ketchup into after it had cooked 24 hours in the crock-pot.

    I didn’t find that the higher sides affected the reduction time too much. I had the oven at 200 and it reduced to a ketchup consistency in about 3 hours. For the conserva I reckon it’ll take the same time because I won’t have added any vinegar or other extra liquid to the recipe.

    Looking forward to trying this with my last 10lbs of farmers market tomatoes.

    • Renee Schettler Rossi says:

      Laura, terrific to hear! Appreciate you taking the time to let us know, and envying you that stash of tomato paste…

  12. Vicki says:

    Made this recipe for the first time tonight. Wasn’t that hard. I ended up with about a cup of paste. Also, this is extremely salty. I used tomatoes from the farm. Had good flavor but way too salty. I like to taste the tomatoes and it’s hard to notice anything but salt.

    • David Leite says:

      Vicki, I’m sorry the paste didn’t turn out as expect. My guess is you over-reduced it. With half the yield (1 rather than 2 cups), I can see that it would be indeed way too salty. To salvage it, I’d suggest, stirring in some store-bought paste. Are you sure you had 10 pounds of tomatoes to start?

    • Dave says:

      Vicki, see my earlier post; Rosetta’s book gives weights, using 0.7% salt. I also track reduction by weight, seeing 8x to 10x reductions. Remember the traditional recipe is a preservation technique in place of refrigeration, while we’re after optimum flavor.

      My all-time favorite tomatoes for this are dry-farmed Early Girls from the Santa Cruz region, available in various California farmers markets in season.

  13. Vicki says:

    I actually used a scale and weighed ten pounds of tomatoes. I ended up with one pint. It didn’t look like it was going to fill a pint, but it did. I thought the salt was needed to help preserve it? If not, next time I will just cut the salt down a bit. I covered the jar with evoo. Used it yesterday in my pot roast gravy. Was fine..just didn’t have to add more salt. I’m tomatoed out! Made 8 quarts of sauce and 22 pints of ketchup, plus the paste! I give the ketchup out as gifts. Just can’t beat homemade (sorry Heinz, you can keep your high fructose corn syrup). Other than being a bit salty, it was still good. I will follow this recipe again and just cut back on the salt next time.

    • David Leite says:

      Vicki, wow! I thought I was a tomato-product nut. (I’m not crazy about eating raw tomatoes.) I think you have done your Love Fruit duty for the season. Re: the salt, my guess it’s used more for drawing out the liquid so that that the tomatoes can concentrate in flavor and texture. If you make it again let me know how it turns out.

    • Heather says:

      Vicki, I am looking for a good ketchup recipe to replace the Heinz ketchup (or Masterfoods Big Red in Australia). Would you be willing to share yours?

  14. steve f says:

    Dear David. I’m so happy to find your site. I’m interested in your grandma’s recipe. I love rustic old school cooking. Larousse has been my go to forever. Anything old school is important to new school. I have used your site to train my daughter. Thank you.

    • David Leite says:

      steve, welcome! I so glad you found us. And if there is anything your daughter needs, please let me know.

  15. Yolanda says:

    Can you can the above recipe in jars and cook in water to preserve so you don’t have to keep in the refrigerator.

    • Beth Price says:

      Hi Yolanda, this is my go-to resource for canning questions, http://nchfp.uga.edu. You could also freeze the paste in ice cube trays and have recipe sized portions ready for use.

    • Dave says:

      Hi Yolanda. First, for any food safety question like this one should use a discussion thread like this as a source of ideas to research, but not as an authority. Yes, chase the canning links, don’t bet your life on anything we say here.

      That said, botulism is the primary canning risk, and is less of an issue below threshold pH acid levels. I ferment my own hot sauce, and use a pH meter to insure that even at the start botulism is not a threat. Tomatoes are generally acidic enough that one doesn’t worry, and these tomatoes are unusually concentrated, increasing that acidity.

      Now, look at tradition. These preserves were not chilled in Sicily; it wasn’t an option. On the other hand, they were much more heavily salted than our modern formulations. They were often stored without air contact, if one counts the layer of oil as protection.

      The classic trap is to apply modern improvements to traditional recipes, without understanding the consequences. Most botulism deaths in Alaska come from using a plastic pail where a seal skin would have been used before.

      • David Leite David Leite says:

        Thank you, Dave. And, Yolanda, I cannot stress enough what Dave says: We are a source of recipes, but we are not health experts. We do our damnedest in researching, but you should always, always go to the health pros if you have questions.

  16. Jeanette Creech says:

    Hi Rosetta, I’m going to try this recipe today. My tomatoes are fresh and ripe. I can’t wait. Thank you so much for sharing.

    • Renee Schettler Rossi says:

      On behalf of Rosetta, you’re very welcome! Would love to hear how your tomato paste turns out, Jeanette.

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