Can You Reheat Pesto Pasta?

Short answer
It's perfectly safe to reheat pesto pasta, provided it has been refrigerated within an hour of being cooked and is no more than two days old. It won't be as good as it was fresh, but in a bizarre twist, the reheating process can even make it healthier for you.

Long answer
We've previously outlined our preference for only heating fresh pesto using the residual heat from the pasta rather than applying direct heat from your hob, oven, or microwave. When it comes to reheating a pesto pasta dish, though, it's perfectly safe, provided it has been refrigerated and is no more than two days old. The taste and texture just won't be quite as good as when they were fresh.

From a safety point of view, there's no issue, but intriguingly, the pasta could even be better for you the second time around. In 2014, a study by the University of Surrey discovered that there's something quite remarkable going on behind the scenes when you reheat pasta, which is not only good for your blood sugar levels but can even result in you absorbing fewer calories.

Pull up a chair; let's have a quick science lesson.

When your body starts to break down a high-carbohydrate food like pasta, it causes a sudden spike in blood glucose levels, prompting your body to create insulin to bring everything back down to normal levels. The body is pretty good at doing that, almost too good, because when your glucose levels return to normal, you start to feel hungry again. This is why dieticians are constantly nagging us to switch to whole-meal carbohydrates because they are higher in fibre and take the body longer to break down.

It turns out that cooking, cooling, and then reheating pasta change the starch's structure to become what scientists call a resistant starch. That basically means the body treats it just like those high-fibre pastas, meaning you don't get the huge glucose surge. That's great news for people suffering from diabetes, but it's good news for everyone else too, because the process can even result in fewer calories being absorbed by the body.

The best ways to reheat leftover pesto pasta
If, after reading this, you're tempted to whip up an extra couple of servings of pasta for reheating the next day, we strongly advise keeping the pasta and pesto separate. That will mean you can simply warm the pasta for 30 seconds in gently simmering water before combining it with the pesto in the same way you always do. If, however, you've accidentally made too much and your pesto and pasta are already mixed, you have a few options...

Sauté or stir-fry
You already know we don't normally condone heating pesto on the hob, but in the case of leftover pesto-pasta, a quick sauté in a wok or saucepan with a little vegetable oil is perfectly fine with us.

Microwave
Add a couple of teaspoons of water to your leftover pasta, cover with cling film, and microwave on the reheat setting for 30 seconds. Stir the pasta, return it to the microwave, and continue this process until the pasta is piping hot. It's not a Michelin-starred technique, but it works.

Bake in the oven
There's no shame in oven-baking leftover pesto pasta. It completely changes the texture, but in a different way, not necessarily in a worse way. Covering your pan with tinfoil will limit moisture loss and help prevent the pasta from burning on the edges. It should need no more than about 10-12 minutes in a 180°C oven.

A quick note on air fryers and pressure cookers
We all know air fryers are awesome at creating the crispiest, healthiest chips, but when it comes to reheating foods like pesto or pasta, they are hopeless. As for pressure cookers, well, you could use the 'warm' function, but we think it's a waste of electricity compared to the much better options outlined above.