Anyone who owns a refrigerator knows that it possesses the strange ability to transform food. The remnants of your Sunday curry night are brightened, your lasagne becomes a delicious, messy gloop. Put simply, it is better the next day. What alchemy is afoot here?
When you cook a dish, whether it is in a saucepan on the hob or in a large baking tray in the oven, reactions happen between the aromatics in a recipe. Think garlic, wedges of onion, beads of cumin, tendrils of cilantro. This produces flavour molecules. But where the real magic happens isn’t what you would expect. As you cool a dish, these reactions continue to take place, simmering just below the surface (pun intended, and apologised for). This produces even more, and sometimes new, flavour molecules.
If you eat a dish right after you have constructed it, more often than not what you taste are the individual flavours – you notice the musky cumin, the herbaceous rosemary. But after leaving it to its own devices, and reheating, it is harder to distinguish between the discrete flavours in attendance. What you taste, instead, is the result of the marriage between all the individual aromatics. You notice less of ‘hey, that’s cumin!’ when the flavours intermingle and get to know each other. The result? A more well-rounded taste. Umami, the illustrious sixth flavour, becomes more perceivable.
That isn’t all. When cooled, flavour molecules are better able to impregnate the protein or starch in your dish. Potatoes soak up a curry sauce, lentils saturate themselves with broth, the cauliflower in your aloo gobi tastes less of, well, cauliflower. This is all down to the structural transformation the starch or protein goes through when cooked and subsequently cooled, trapping the flavour compounds within as the temperature plummets. The texture of the sauce itself changes from something thin and watery, to a thick velvet gloss.
But not all leftovers are created equal. While curries and stews have much to gain from some time in the refrigerator, some dishes are left worse for wear. Salads already slick with vinaigrette wilt into a tangled leafy mess, thick batons of fries become mealy, seafood – well, let’s not even go there. How is one to navigate the seemingly capricious world of leftovers and decide what will make a better next-day meal? The answer, my dear Watson, is elementary. Anything that contains a multitude of aromatics, be it herbs, spices or alliums, make leftover heroes. An omelette brimming with garlic, chives and chilli is much improved after some rest, a plain omelette less so.
Now that you are armed with the science behind leftovers, what will you do with it? If you are a meal prepper (and therefore a better human than I am), take note. Meal prep curries, or pillowy noodles of lasagne striated with herby sauce. Leave that sandwich behind, or you will be the poorer for it. You want something that shines after being reheated, rather than something that leaves much to be desired. Season your dish well the first-time round, and then embellish even more after a reheat – tufts of herbs, a flourish of lemon juice.
Now, a mandatory disclaimer. Leftovers, while great, can be a risky business if you aren’t careful about it. Please, handle food safely. After cooking a dish, refrigerate it as soon as you can – no languishing on the kitchen counter for hours on end. But never too quickly – plunging a lunchbox full of food that radiates heat into a refrigerator can warm up the rest of its contents. You want food to cool to about 26 to 30 degrees (roughly room temperature) before you can pop it in for a chill, which should take about 30 minutes. Treat your leftovers well and it will behave itself.
Welcome, young grasshopper, to leftover nirvana.
Image Credit: Kathleen Franklin