Why You Should Save Your Pasta Water
These are days of hanging on to your scraps, using what you have, and being creative with leftovers. If you have a few boxes of pasta hanging out in your pantry for low-lift, high-satisfaction weeknight meals, you’re also producing something that you might not realize is worth keeping: Your pasta water.
There’s nothing fancy about it. Pasta water is just what it sounds like: cloudy, salty water that’s leftover when you cook a vat of spaghetti or penne or whatever other pasta shape you have. When you simmer noodles in water, they release starch, giving the water that murky appearance. How starchy it is depends on your water-to-pasta ratio. If you cook a pound of pasta in a half-gallon of water, the water is going to be starchier than if you cook a pound of pasta in a gallon of water.
OK, so let’s say you cooked some noodles, scooped them out, and now you have a vat of pasta water. What should you do with it? The most obvious answer is to make a sauce for the noodles you just cooked. Using a little bit of pasta water is the key to making smooth, restaurant-level sauces. Some of the most classic Italian pasta dishes, like cacio e pepe and carbonara, depend on the starchy, binding power of pasta water to make the sauce. But even if you’re not making your own sauce, pasta water can help bind sauce to noodles. Toss your noodles in some pesto and a quarter- to a half-cup of pasta water, and the water will help the pesto coat the noodles. Add a little pasta water to pretty much any sauce you’re making, and it’ll help it stick to the noodles. You can even substitute the pasta water for the milk when you make boxed mac and cheese. It doesn’t have to be fancy to work.
Pasta water is also worth saving for homemade bread, as I recently learned thanks to a tweet from Nigella Lawson. Just substitute the pasta water for whatever amount of water you’d normally use in your dough. The starch in the water helps the bread’s rise. I used it in both sourdough boules and focaccia with great effect. Just taste the water before you add it to assess its salt level. If it’s very salty, adjust how much salt you add to your dough.
Though it might not be practical to save all your pasta water, depending on how much pasta you’re consuming and how much freezer space you have, you can also freeze it. I sometimes freeze mine in an ice cube tray so I have it on hand to add to pan sauce, or in quart containers to use in vegetarian soups as a replacement for or addition to vegetable stock. 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. It’s just another way to get the most out of what you have, and limit how many times you need to go out on a grocery run.