Reheating Spinach – Is It Safe? Everything You Need to Know

Spinach is one of those leafy green vegetables that kids love to hate but somewhere on our journey to adulthood, we realize it is surprisingly delicious.

In grocery stores, it’s not hard to find several different ways you can buy spinach, from fresh to frozen, in small, premade salad packages to massive bags or tubs that misleadingly look like they will feed an army of ravenous vegans.

A few years ago, an interesting myth began circulating about the safety of spinach – more specifically, reheated cooked spinach.

Which, of course, leads us to the question: Can you reheat spinach? Yes, you can reheat spinach. Spinach is best when warmed slowly on low heat. No matter which appliance you use to reheat your spinach, make sure it is warmed gradually and not blasted with heat in a high-power microwave or oven broiler.

If you do happen to have leftover spinach, you can freeze or refrigerate them to warm up for another meal. This may, however, lead to controversial dinner-time conversations, so before you do, it’s a good idea to know the facts behind the warnings about reheating spinach.

The Reheating Spinach Myth

There’s a belief that became very popular after getting some internet attention from the Netherlands and subsequently, the UK that the nitrates in spinach will become toxic if reheated.

When heated, nitrates begin to break down and become nitrites, which can then convert into nitrosamines. Nitrites can affect oxygen intake and nitrosamines are a known carcinogen.

Let’s address nitrates first.

Nitrates are a single nitrogen atom with 3 oxygen atoms attached. When we eat naturally occurring nitrates, the digestive process breaks it down, removing 1 oxygen atom and creating a nitrite.

Nitrites, on their own, are mostly harmless and can actually be really great at preventing botulism, so it’s commonly added to cured meats. 

When nitrates are exposed to high heat or the bacteria in your gut, they are further broken down. If it loses one more oxygen molecule to your gut bacteria, it becomes Nitric Oxide, which is very good for your body as it helps send important signals that help regulate blood pressure. 

However, high heat can alter the chemical compound entirely, turning them into carcinogens. This is where the myth began. 

Let’s talk more about nitrosamines before drawing any spectacular conclusions. Nitrosamines are commonly found in cosmetics, condoms, tobacco products, cured meats, and pesticides.

If reheating spinach makes you feel threatened, you will also need to stop wearing make-up (and washing), find a new way to prevent unwanted sexual consequences, quit smoking and eating deli meats and bacon, and, of course, eat and use only organic products.

If that sounds a little extreme, here’s another fun fact about nitrosamines. If you have a diet rich in antioxidants, which come from foods like leafy greens, they will help prevent nitrates from converting into nitrosamines.

Eating your spinach in the first place can protect you from the unlikely possible harm of reheating it again later. 

Finally, it is only very high heat that will convert naturally occurring nitrates into nitrosamines, so avoid burning your spinach to a crisp, and you will be absolutely fine.

Simple Steps to Reheating Cooked Spinach

Knowing what you now know about nitrates and spinach, it’s a good idea to first steam your spinach, rather than fry it to a crisp.

From this point, you’ll want to refrigerate any leftovers as soon as it’s cool and make sure it’s stored in an airtight container to prevent any bacteria growth.

To be brutally honest, in most foods cooking them once will degrade the nutritional content. Reheating them yet again will bring that nutrition down even further.

The flip side of that coin is that some nutrition is better than no nutrition, and food wasted—which includes either throwing it away or overeating, as that’s just as wasteful—is good for no one.

When you’re ready to eat what was left of your leafy greens, you can choose from a few different appliances to warm them back up.

Using the Microwave to Warm Up Your Spinach

If possible, adjust your power setting to medium before reheating your spinach. Make sure you place it into a microwave-safe dish, preferably one made of glass or ceramic – never plastic – and with a lid.

If your dish doesn’t have a lid, use a microwave-safe splatter guard, especially if your spinach already has butter or other toppings on it.

Spinach is quite delicate, so it won’t take long to warm up.

For best results, spread the spinach out as much as space will allow to help it heat evenly. Use only short bursts of 30 seconds and stir the spinach around between each one. Don’t overheat it, but stop as soon as it’s steaming.

Warm Up Previously Cooked Spinach on the Stove

Again, to preserve the nutritional content and safety of your spinach, you want to reheat it over low to medium heat in a pot or a pan on your stove.

It’s a good idea to stir frequently to make sure it doesn’t stick to the bottom of your pan. Once your cookware is heated, the warming up process for your spinach will take only a few minutes.

It’s important to keep an eye on your spinach so that you don’t overheat it.

Reheating Foods With Spinach in Them

Spinach on its own is a treat for your tastebuds, but there are so many ways to dress up this green veggie that we thought it would be smart to talk about how to reheat some different dishes that include spinach.

How to Reheat Spinach Artichoke Dip

Warming up yesterday’s spinach and artichoke dip is much the same process as it was baking it in the first place. If you’re using the oven, lower temperatures for a longer period of time is going to get a more thorough heat than trying the fast and furious technique.

Try 350F for 15 – 20 minutes, checking it occasionally until it looks like the perfect temperature for your liking. 

If you prefer to use the microwave, it helps to use smaller portions. A large dish won’t heat evenly in the microwave, so try single servings or be prepared to stir to distribute the heat. It’s best to work in 30-second intervals until you get the right temperature. 

Reheating Spinach Soup

The best way to reheat spinach soup is on your stove over low to medium heat and stirring constantly, especially if it’s a cream of spinach soup.

If you don’t have a stovetop handy, or the patience to wait and stir, you can use the microwave but beware of splatter. Use a splatter guard and only heat in bursts of 30 seconds, stirring each time.

If you leave your soup in for too long at one time it’s likely to bubble over and make a mess in your microwave.

How to Reheat Spinach Pie

Spinach pie, also known as Spanakopita, is a phenomenally enjoyable Greek dish made of flaky pastry-wrapped spinach and feta. Served warm it will melt in your mouth.

To reheat without damaging the delicate flakiness and melt-in-your-mouth quality, you must use your oven or a toaster oven.

Depending on whether you’re reheating a full-size pie or a hand-held single serving, you’ll want to slowly toast at 350 degrees for 10 – 20 minutes, checking often to make sure it doesn’t get too golden.

If you decide to use your microwave, you should prepare yourself for a slightly soggy crust. To avoid this as much as possible, place a paper towel on the microwave-safe plate before warming.

Reheating Spinach Quiche

When it comes to spinach quiche, the quiche part of the equation is the trickier part to reheat well. If you’re not careful, you might end up with a chewy, rubbery pie.

But if done right, it can taste just as delicious as the first time it was served. 

If you’re heating a spinach quiche from frozen, you can stick it directly in your preheated oven at 350F. You’ll want to cover it with aluminum foil, however, to make sure it doesn’t dry out.

Bake for around 30 minutes, checking it at 25 to test the heat levels and only leaving it in longer, uncovered if it needs to be.

As with any type of pie, it’s good to let it sit for 10 minutes or so before serving, otherwise, it’s difficult to serve and is more likely to crumble. 

If you have a spinach quiche in your fridge, it will warm up more quickly. If your oven is hot at 350F, the quiche should only take 15-20 minutes to warm up again. 

If you have a toaster oven, you can use the same temperatures and timing as above. In both cases, your quiche will warm more evenly if it’s placed in your oven or toaster oven in individual servings, spaced apart from each other.

The microwave is not the best way to reheat your spinach quiche, but if it’s your only option, it is possible. Generally, you only want to heat things in a microwave as long as absolutely necessary.

When it comes to quiche, however, there is a secondary option you might consider. For nutritional content, stop as soon as it’s the right temperature.

If the texture is important to you, however, there is a trick that you might find useful.

Heat up your quiche 30 seconds longer than you think you need to and then let it sit for at least 5 minutes. The extra time will get it slightly too hot and as it cools down it will release steam, letting go of some of the moisture that might lead to a soggy crust.

It’s not perfect or foolproof, but it’s a technique that works for some. 

Best Ways to Store Spinach

Cooked spinach is oddly much easier to store than fresh spinach. Once cooked and cooled, you simply want to transfer your spinach to a container with an airtight seal and place it in your fridge. I found this one on Amazon and it really does the job!

Cooked spinach will last up to a maximum of 5 days if properly stored in your fridge. 

Fresh spinach can be frustrating to store. If there is any moisture in the leaves at all, they will wilt and rot, emitting a foul smell and encouraging all their neighboring leaves to follow suit.

To prevent this from happening and keep your spinach as fresh as possible for as long as possible, line the container with a paper towel before placing it in your fridge. This will help absorb any moisture that might be lurking.

It’s also much better to store your spinach in a container rather than a bag because crushing the leaves will lead to them wilting and rotting as well. 

Can Spinach Be Frozen and How?

Spinach can absolutely be frozen and it can be a great choice if you’ve got more spinach than you can eat in a few days.

Freezing your leafy greens will protect the nutritional content better than leaving them in the fridge will, and your spinach will last for 6 months to a year in your freezer. 

Once defrosted, the leaves won’t be crisp and fresh any longer, so it’s not an ideal way to store your salad greens. However, if you plan on cooking your spinach in the future, cleaning, blanching and freezing is a perfect solution for garden-fresh spinach year-round.

If you’re truly working with spinach straight from the garden, you want to wash the leaves multiple times to make sure you get all the dirt off. If it’s supermarket fresh, you might be able to skip this step if the packaging states that your spinach is pre-washed. 

Blanching simply means steaming your spinach for a very short period of time, usually 2 minutes, and then immediately placing it into an ice bath to stop the cooking process. You want to kill any and all harmful bacteria, but not actually cook the spinach. 

Once the spinach is blanched, it’s crucial to get all the water off before you freeze it. Frozen water damages the structure of your spinach, so it will be mushy when it defrosts if you don’t dry it well first.  You can use a salad spinner and/or carefully blot with a towel or paper towel. 

Using a freezer-safe Ziploc bag is probably the easiest way to freeze your spinach, but you can also use a Tupperware container.

The trick is to pack in the leaves as much as possible to reduce the amount of space that air can sneak into between leaves. If you’re using a bag, you can further squeeze out any air as you seal it. If done well, your spinach will stay fresh for a year.

Related Questions

Is Creamed Spinach Keto?

Spinach itself is a keto favorite because there is a wide variety of nutrition, including protein, packed into a serving size that is very low in calories and carbs.

When you add cream to the mix, you do change the story a little, but it’s still possible to be Keto.

Look for full-fat dairy, and make sure you check the carbs and sugar content on your parmesan, cream cheese, sour cream, or any other ingredients you add. 

How Much Spinach Is Too Much?

Some extremists have declared that because spinach is a source of oxalic acid, which binds with calcium and other nutrients so that your body can’t process them, it’s actually toxic and can be fatal.

To reach the level of fatality, you’d have to be eating approximately 7.5 pounds of spinach a day. Considering how light spinach is, this is highly unlikely.

In fact, with all the incredible nutritional value packed into spinach, you would be best served by eating a cup of fresh spinach every day.

Can Spinach Cause Diarrhea or Gas?

As a vegetable, spinach is not known to create any digestive distress, including diarrhea, gas, bloating or constipation.

However, it is one of the more likely leafy greens to be infested with the E. coli bacteria and norovirus.

Both of these contaminants can cause food poisoning and, as such diarrhea or vomiting. The easy fix is to simply make sure you wash your spinach well before eating it, especially if you’re eating it raw.