Can You Reheat Spinach?

Yes, you can reheat spinach. The common warning against it comes from a concern about nitrates, but for most home cooking situations the risk is overstated. The more practical challenge with reheated spinach is texture: cooked spinach releases water as it sits, and reheating releases more. Handle that and the result is fine.

The Nitrate Question

Spinach is naturally high in nitrates. When cooked spinach is left at warm temperatures for extended periods, bacteria can convert those nitrates into nitrites, which at high levels are a concern particularly for infants. However, the key conditions for this are warmth and time. Spinach that is refrigerated within two hours of cooking and reheated quickly to serving temperature does not spend enough time in the bacterial growth zone for this to be a meaningful concern for healthy adults. The NHS and major food safety bodies do not list reheated spinach as a high-risk food for adults. For babies under one year, avoid reheated spinach as a precaution.

Can You Reheat Spinach?

Yes. Cooked spinach keeps for three to four days in the fridge in a sealed container. Refrigerate within two hours of cooking and reheat only once. The food safety risk is low for adults; the quality risk is higher, since each reheating makes the spinach more watery and the leaves more broken down.

The Key Step: Drain Before Reheating

Before applying any heat, squeeze or drain as much liquid as possible from the spinach. Use your hands or press it against the side of a sieve. This single step is the difference between reheated spinach that works as a side dish and a watery, flat result. Spinach is around 91% water, and it releases a significant portion of that during the first cook. What remains in the fridge has already absorbed some of that liquid back, and reheating drives it out again.

Reheating Spinach on the Stovetop

The best method for texture control and removing excess moisture as it heats.

1. Drain and lightly squeeze the spinach first.
2. Heat a pan over medium heat with a small amount of olive oil or butter.
3. Add the spinach and stir continuously. Any remaining liquid will evaporate quickly.
4. Heat for two to three minutes until hot throughout. Season again before serving, as salt draws out additional moisture and flavour fades during refrigeration.

Reheating Spinach in the Microwave

Fast and acceptable, though you’ll get more moisture in the bowl than with the stovetop.

1. Drain the spinach and place in a microwave-safe bowl.
2. Cover loosely (do not seal tightly, as steam needs to escape).
3. Microwave on full power for 45 to 60 seconds.
4. Drain any released liquid before serving. A fine sieve or a quick press with a spoon works.

What Doesn’t Work

• Reheating without draining first: the extra liquid makes the spinach waterlogged and dilutes any seasoning
• Oven reheating: spinach dries out unevenly and the leaves at the edges burn before the centre is warm
• Reheating spinach in a creamy sauce: the sauce can separate and the spinach releases more water into it. If you must, use low heat and stir constantly

Spinach in Dishes: Lasagne, Curries, Soups

Spinach incorporated into a larger dish (lasagne, saag, soup) reheats as part of that dish with no special treatment needed. The surrounding ingredients absorb the released moisture, which is less of a problem than with plain spinach reheated alone. Follow the reheating guidelines for the main dish rather than treating the spinach separately.

Which Method Should You Use?

Q: I put spinach in a lot of things, I like to eat it with my greens, I also love it on my subs. I reheated it all the time but was recently told it is very unhealthy for me to do that. Is it safe for me to reheat spinach?

A: It is generally advised that you do not reheat spinach as it creates a compound that your stomach is unable to digest. In young children under six months, it should be avoided entirely.

The Reason

When spinach is heated, stored, then reheated, bacteria that is present will convert enzymes into a toxic protein. Our blood carries oxygen all around our body, and it does so with proteins. However, the protein created by spinach is called methaemoglobin, and it does not carry oxygen. That means your muscles, organs, heart and brain are not getting as much oxygen as they may need. Obviously this is something that should be avoided at all costs.

In adults, this is not as prevalent as it is in young children. Children exposed to this protein often develop “Blue Baby Syndrome” which is indicated when the lips turn blue from lack of oxygen. As adults, we can tolerate more of this protein without adverse effects but should be avoided in large quantities.

As much as we love to eat our reheated greens, or not give it a second thought when we pop our sub into the microwave, we need to be more cautious about what we heat up! While it may not kill you, it is not advised to eat reheated spinach.