What we throw down the drain is reserved for the silkiest pasta sauces in Italy.
Here's how to use l'acqua di cottura in your Italian cooking.
The secret to silky sauces
A silky sauce is simple to make.
It's a matter of emulsion.
Ever wondered why a plate of steaming carbonara in Rome tastes eternally divine but at home is nowhere near?
That's because pasta sauces are brought together quickly in a pan in Italian restaurants, there's a cooking detto in Italy that says the pasta sauce should be made in the time it takes the water to boil and the pasta to cook. Ovviamente not slow-cooked ragù alla bolognese, we're talking carbonara, amatriciana, arrabbiata or alle vongole...
And did you know that these sauces all rely on l'acqua di cottura for their silky texture?
Pasta is Italy's staple food, it's their numero uno, their pride and joy. Something as simple as flour, salt and water has been brought to pure culinary perfection so to have it served 'right' is fundamental for an Italian. I've seen many visibly mortified people let down by an overcooked plate of tagliatelle or an unsalted spaghettata!
You're supposed to bring it to the table perfetta, with nothing needed except a sprinkling of Parmigiano, and not even that sometimes - see our post on orecchiette...
In a day in the culinary life at lunchtime you'll hear, "Metto su l'acqua?" Shall I put the water on?
Because first it's the water, then it's the sauce.
Most people open their fridge, like we do, and fashion a sauce from what's in it. A trip to the market may have brought home seasonal vegetables, beautiful cheeses and cured meats like Speck or pancetta providing inspiration for incredible pasta sauces made 'al momento' but remember, some of the most iconic dishes are the simplest; Rome's traditional cacio e pepe is only three ingredients: an emulsion of pecorino romano, black pepper and l'acqua di cottura.
What is l'acqua di cottura?
Translated simply as 'the cooking water', l'acqua di cottura is a combination of salt, pasta starch and hot water. As the pasta boils, it releases starch into the cooking water resulting in a thicker consistency. Instead of adding cream to a sauce to make it 'creamy', there's a scientific trick to make a glossy 'cream' from the pasta water which would have been destined for the drain! What's the difference?
The way an emulsion sticks to the pasta.
An emulsion is technically a combination of components (in this case starch, water and fat) that doesn't like to merge, but blended in baby steps with quite a bit of mixing will produce one liquid.
The beauty of a blended emulsion sauce, instead of a cream-based sauce, is how it clings to the pasta. Pasta and sauce should be 'as one'. When you have a quattro formaggi but there's watery liquid at the bottom of the bowl, you've done it wrong. Same with carbonara, if it's clumpy and bumpy and doesn't stick to the spaghetti, once more, that's not an emulsion.
To create a silky sauce in the time it takes to boil a pot of pasta (that's up to 12 minutes) takes a little skill and some practice but from the first sauce you make, you'll already notice the difference.
How to use l'acqua di cottura in your cooking.
One way is by saving a cup of cooking water before draining the pasta but it cools rapidly so doesn't work as well, plus, what if you need more?
The best way is the method chefs use to bring pasta and sauce together in restaurants...
Instructions:
Bring a large pot of water to boil and add coarse sea salt (7g salt to 100g pasta).
Start cooking your pasta sauce in a deep pan. Many sauces start with chopped onion or garlic sauteed in olive oil or the meat you're using. Carbonara starts with guanciale, Arrabbiata starts with garlic.
Add the pasta to the boiling water and cook according to its packet instructions minus two minutes.
When your sauce ingredients are all cooked in the pan, drop the temperature to the lowest heat and begin to add the starchy water one ladle at a time, mixing and tossing the sauce until it becomes silky and smooth. Add a few spoonfuls extra as the pasta will absorb liquid as it cooks for the last two minutes.
When it's ready to drain, lift the pasta from the pot with a spider strainer or gnocchi spoon for pasta corta, or tongs for pasta lunga, instead of straining the water into the sink. (If you do strain it, remember to keep a cup aside). Turn up the heat and place the pasta straight into the sauce.
Keep tossing the pan to mix, adding more acqua di cottura as you go, until everything is beautifully combined and glossy, then remove from the heat and serve immediately with a chunk of parmigiano and a grater.
COOKING TIPS:
A knob of butter will make tomato less acidic and helps the sauce come together with a splash of hot pasta water.
L'acqua di cottura is essential to make pesto into a silky sauce that clings to the pasta.
NOTES:
Cacio e pepe is made separately in a large bowl where l'acqua di cottura is added to grated Pecorino Romano and black pepper until a silky sauce is formed.
How to Cook Pasta, The Italian Way has all the tips you'll need for the perfect pasta dish.
And if you do happen to be in Rome, check out our post AMO ROMA - Get Incredible Pasta, Pizza and Gelato in the Eternal City for our favourite spots.
A presto amici!