5 Best Ways to Store Tomato Paste After Opening a Can – No Waste

Once we open a can of tomato paste and use only 1-2 tablespoons, what’s the best way to store the leftovers? I’ve been cooking with tomato paste all my life, and I’ve learned that even when stored in the refrigerator, it can spoil quickly if not handled properly. There are a few easy and effective ways how to store leftover tomato paste to stay fresh longer. Whether you’re cooking often or only occasionally with tomato paste, these tips will help you prevent waste and save money. Buying larger cans of tomato paste is much more economical, and when you know the best storage methods, you won’t have to worry about the leftovers going to waste. Check proven by time, practical ways to keep your tomato paste fresh for future recipes.

*In the photo above, I show my test; the result is on the page after the oil method.

5 Best Ways to Store Tomato Paste After Opening a Can:

The mustard method is to store tomato paste in the refrigerator (My favorite!)
Vegetable oil way to store tomato paste in the refrigerator.
Freezing tomato paste in a large ziplock bag.
Freezing tomato paste in baking paper.
Freezing tomato paste in small ziplock bags.

Always Remove Tomato Paste from the Can For Storing!

It’s important to transfer the tomato paste from its original metal can to a dry glass or food-grade plastic airtight container after opening to minimize air exposure. Never store opened tomato paste directly in the metal can in the refrigerator. The open metal can react with the acidity of the tomatoes, potentially affecting not only the flavor but also the safety.

1. My Favorite Way To Store Tomato Paste After Opening Can – Use Mustard!

Mustard isn’t just a flavorful condiment — it’s also a natural preservative and works so well to keep tomato paste fresh after opening a can! You will be surprised how well it works! I like this method because I don’t add anything directly to the tomato paste. The mustard method is my favorite way to store tomato paste in the refrigerator for a month or longer, if you need, of course. However, if you seldom use tomato paste better to freeze it.

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Mustard Method To Store Tomato Paste:

Place tomato paste in a clean and dry jar. Cover the surface of the lid with a layer of mustard, as I show in the photo. Mustard not touching the tomato paste. This simple step helps prevent the spoilage of tomato paste. Close the lid tightly and label with a date when you store it.

When you need some tomato paste, use a clean and dry spoon. Scoop out how much you need, then secure the lid tightly and return the jar to the refrigerator.

2. Use Vegetable Oil To Keep Tomato Paste Fresh After Opening Can

The vegetable oil method is another effective and time-tested way to preserve leftover tomato paste. This creates an airtight seal that helps keep the tomato paste fresh in the refrigerator for a month. While this method does add a light layer of oil, it’s generally not a problem for most recipes, especially those that already include oil. It’s a classic, old-fashioned kitchen trick that still works like a charm today.

*The best to use is odorless vegetable oil.

Vegetable Oil Method To Keep Tomato Paste Fresh:

Place tomato paste in a clean and dry jar. Smooth the top surface of the tomato paste in the jar. If some tomato paste on the side or mouth of the jar, wipe it off. Pour a small amount of oil to cover the top of the tomato paste. The oil is a barrier against air and mold. Label the jar with the date. Store in the refrigerator.

Take tomato paste with a dry, clean spoon. Smooth up the surface of the tomato paste and cover with oil again if needed.

Tomato Paste Storage Test: 3 Methods After 1 Month

I ran a simple experiment to learn how long tomato paste can stay fresh using 3 different storage methods. You see the result in the photo above after the tomato paste jars were in the refrigerator for 35 days. I prepared three test jars: one with plain tomato paste, another sealed with a layer of olive oil, and the third with a mustard on top of the lid.

The result with just tomato paste little surprising to me. I didn’t expect the plain tomato paste to develop visible mold after the 3 weeks. However, the mold was probably not visible for some time, so this method is good only for a few days.
The olive oil-sealed tomato paste jar remained fresh and mold-free.
The mustard remained fresh and mold-free as well.

This test showed that adding a protective layer of olive oil and mustard on the lid can significantly extend the shelf life of leftover tomato paste in the fridge for a month or longer.

It is just a test. In real life, if you don’t know when you are going to use tomato paste again, the best way to store it is to freeze it.

Is It Safe to Scoop Off Mold from Tomato Paste and Use It In Cooking? The Answer Is No!

📌Why can’t we just remove the mold and use the rest of the tomato paste? The mold has roots called huphae, and they are invisible to us. We remove visible mold, but the rest of the tomato paste is infected with mold’s roots. Heat can’t destroy mold’s hyphae and the harmful mycotoxins they produce. So, moldy tomato paste should be discarded and should not be used in cooking.

3. Freezing Tomato Paste In Large Ziplock Bag

One of the easiest and most effective ways to store leftover tomato paste is to freeze it in a large ziplock bag. This method keeps your tomato paste fresh for up to 6 months. Why do I love this method? We don’t need to use anything — no baking paper or trays required. Just the bag! It thaws quickly in the microwave ( on a cooking dish directly) and saves both time and waste in the kitchen.

Freezing Tomato Paste In Large Ziplock Bag Method:

I turn out a ziplock bag. Then I place the cutting board inside the bag for convenience to transfer the bag with paste to the freezer. With a spoon, place the tomato paste on the top of a ziplock bag in portions. Freeze it and remove the cutting board. Then roll the bag so it turns right side out, and all my frozen tomato paste portions are inside the bag. Remember to label the freezer bag with the date.

For the best result, thaw the tomato paste in the microwave or naturally in the refrigerator before use. However, I often just place it frozen in the skillet and let it thaw there. Nobody is perfect:)

Tomato Paste Squash Spread Photo

4. Freezing Tomato Paste In Baking Paper

The easiest way to freeze tomato paste is on baking paper! I learned this method just recently from the Internet. Cut 5-6-inch ribbon or squares out of baking paper. Place 1 or 2 tablespoons of tomato paste between parchment paper. It does not become my favorite method because I still need to use a ziplock bag to store it. It thaws quickly and saves both time and waste in the kitchen.

*Remember to label the freezer bag with the date.

5. Freezing Tomato Paste In Small Ziplock Bag

Store tomato paste in the freezer with individual small ziplock bags – a smart space-saving trick. One creative and efficient way to freeze tomato paste is by one or two tablespoons portioning it into small individual zip-top bags. I used a spoon to transfer the paste into each bag, but a wide-mouth funnel also works great and helps keep the sealing area clean—no mess near the zip! What I love about this method is how easy it is to squeeze out the air, which helps prevent freezer burn. When you’re ready to use it, simply cut off the side of the bag and remove the tomato paste.

📌 Tip: To label each bag, I used painter’s tape. Before applying it, I made sure the surface was dry. This tape is easy to write on and holds up well in the freezer—plus, it peels off cleanly when you’re done!

6. Freezing Tomato Paste In Ice Cube Trays

My least favorite way to store tomato paste in the freezer is in an ice cube tray. Spoon portions of tomato paste into the wells of an ice cube tray. Freeze until solid, then transfer the frozen cubes to a freezer bag or an airtight container. It works, but we have to clean the ice cube tray after freezing, and anyway need a ziplock bag to store. The best part of this method – we can make fun shapes (like flowers) of tomato paste!

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May 7, 2025

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