Food Answers: Why do Chefs Reserve Pasta Cooking Water?

We're all about cutting food waste in the kitchen, repurposing leftovers and shining a spotlight on those ingredients with hidden talents in our Why Waste? series.

With that in mind, we turn our attention to murky, salty pasta water. The water that you're left with after boiling up your favourite pasta shapes, which often ends up down the sink. On closer inspection, pasta cooking water is in fact a chef's best friend, with surprising hidden depths.

This starch-rich liquid is the magic ingredient in many pasta dishes, from carbonara to cacio e pepe, and is the secret glue that helps sauces stick to the pasta.

Also, much like keeping vegetable water to build stocks and gravy, you can do the same with pasta water, as well as adding it to pan sauces, soaking and cooking beans, and making fluffy bread.

What to do with cooked pasta water

Keep some pasta water back to add to your pasta dish

As most chefs and home cooks know, when you drain your pasta, it's a good idea to keep back a cup of the cooking water to add to the sauce. Not only will this thicken the sauce, but it will also help it to stick to the pasta.

Dishes like classic carbonara rely on the pasta cooking water to add to the egg mixture and dilute it to obtain a thick and enveloping cream.

Use pasta water for soaking and cooking legumes

You can also use pasta cooking water to soak dried beans. It’s also great to cook beans in, to further add to the unctuous bean broth that’s released when slow-cooking beans for hours.