I am a summer babe, like the Pavement song goes, and born on what’s typically one of the hottest days of the year (this year being no exception). So it goes without saying that I love the summer and all that it entails. (OK, I can do without the humidity.)
One of the best ways to savor summer for the rest of the year is through preserving foods, and Sicilians are masters of making tomatoes last all year long thanks to estratto di pomodoro.
Estratto (estrattu ri pummadoru in Sicilian, sometimes spelled as astrattu and other variants) is deeply concentrated tomato paste that’s reduced through leaving tomato sauce out on large tables in the hot, full sun of summer over the course of a couple days. Watch this video to see how it’s done traditionally.
Forget what you know about tomato paste, this is next level. You take a teaspoon at most and add it to your sauces, soups, and stews for intense umami flavor.
Over the past couple of years, I’ve been lucky to afford picking up the imported version through Gustiamo. But with the pandemic giving me plenty of downtime, close proximity to New Jersey tomatoes, and my ever-present interest in replicating the foods of my culture abroad, I was curious to see if I could recreate it. Who knows when I’ll be able to go overseas again (sigh) and sneak back a jar from my uncle.
Unfortunately, Philadelphia is no analog to Sicily, and to say that our weather is unpredictable is a gross understatement. On top of this, living in an urban environment, my neighborhood Trash Pandas and Squirrel Friends would have a field day with a table full of tomato paste.
After a lot of research and brainstorming, I’ve come up with a method that should work for a multitude of environments. If you love to preserve foods but are short on space, this is a great alternative to canning tomato sauce and can be used for months to come.
FWIW, there are a lot of similar tutorials out there, but a lot of them just tell you to reduce in the oven, nor do they really dive into preservation or telling you what the end result should resemble. Hopefully this will help, and let me know if you have any questions!
Unless you live somewhere with a dry summer climate (Arizona, Southern California, the Florida Keys), it will take quite a bit of work to accomplish evaporating the water in tomatoes to reduce them considerably.
To do this in a similar timeframe to the traditional method, I’ve broken this down into two parts:
- Using gravity to drain the excess water
- Reducing the paste in the oven
Overall, this should take you 2-3 days to make, which is equivalent to the amount of time it takes abroad.
This process yields 80z (236ml) of estrattu.
For the Paste
- 5-6 pounds of tomatoes
- 1/2 cup of Morton’s kosher salt
You can use any kind of tomato for this. I am not a SAN MARZANO OR GTFO!!1! kind of person, but strive to get the best tomatoes available to you, especially if they’re local. As always, the end result is going to be determined by the quality of the original ingredients. Are your tomatoes not great? This is just going to preserve Not Great Tomatoes.
- Large cooking pot
- A food mill
- Cotton pillow case (see note below)
- 2-4 feet of rope
- Extra container to catch liquid
- Spatula or cooking spoon
- Bowl scraper (optional)
- Pyrex baking tray
- Jar and lid for canning
A food mill is crucial for breaking down the tomatoes into pulp and removing the seeds. A blender—immersion or otherwise—won’t work for this, plus the oxygen that’s blended into the tomatoes will start to make them look orangey and pale.
If you have an old pillow case that you no longer use, great. Make sure to launder it without fabric softener before doing this. If you sew, you can also make a similar object using unbleached muslin.
Cooking the Tomatoes
- Cut all your tomatoes in half and put in the pot, making sure to coat them evenly with 3/4 of the salt. Cook over medium heat until they begin to soften and break down.
- Remove from heat and process using the fine or intermediate setting with a food mill.
Removing Excess Liquid
In this part, we’re going to strain the majority of the liquid by creating essentially a giant teabag to contain the pulp using gravity.
Before you begin, strategize a good spot for this to hang and drip. If you can do it outdoors, cool. If not, just have something underneath to collect the water. I hang mine outside if the weather’s good, and over the kitchen sink when it’s not.
- Place your pillowcase or muslin into a container. Make sure it is secure and won’t collapse during the next step.
- Pour the tomato sauce into this vessel and tie up the top with a rope.
- Hang and place something to collect the liquid underneath.
- Let this drip for about 3-4 hours, or when reduced in size by a half.
Don’t panic when you see all the liquid during the initial pour—this is what should happen! All the good stuff is still inside the bag, while the liquid is being strained out. If you want, you can conserve the excess liquid and use as tomato water for vinaigrettes, cocktails, or stock.
Reducing the Tomatoes
Now we’re going to reduce the tomatoes using the oven with as little heat as possible. Most ovens are warm by default, so this makes for a decent substitute environment.
If you are lucky to have an oven with a dehydrator mode, you can use it in this step. The cooking time below may be shorter for you. If not, I will preheat the oven for 30 minutes at its lowest setting and turn it off before placing the paste in.
I recommend using a glass baking dish for this as metal cookware reacts to the acidity of tomatoes. (I haven’t tested this with ceramics or other kinds of cooking dishes.)
- Turn the bag inside out and using a spatula, scrape the entire contents into the glass baking dish.
- Spread the paste evenly, then apply the rest of the salt.
- Place in the oven, check every hour, and stir.
- Remove from oven when reduced to a third of its original size.
- Take about 1 tablespoon of olive oil and fold into mixture.
- Transfer to sterilized jar, pushing out air bubbles.
This should take about 12-15 hours to reduce. If your stove gets cold again, take out the paste and reheat the stove using the steps above.
Like I said, the paste should be ready when it’s reduced to about a third of the original. It should feel really thick, almost akin to PlayDoh or Sculpey. As you stir, make sure to push together the reducing paste—you don’t want to spread this thin and let it dry out. If that does happen, don’t panic. Push the dried out parts into the paste and it should reconstitute.
How to Use
You can use this right away if you’d like. It should last about a month. I mean… use your judgement. We’re adults here.
Tomatoes have a set of unique challenges when it comes to making them shelf stable. If you don’t preserve them correctly, they can mold, grow all sorts of gnarly bacteria, and so on.