Stop Throwing Away Your Pasta Water — Cooking Experts Share an Ingenious Way to Reuse It

Behind every plate of irresistible pasta is a mysterious episode that unfolds during the cooking process. It takes a whole lot of chemistry to resurrect those hardened pasta granules into softer, edible pasta, and of course, boiling water, a study published in the journal LWT - Food Science and Technology revealed. As the boiling water wets the pasta from the exterior, its immense heat pushes and presses it to such extremes that the starch molecules locked in the pasta’s protein matrix are liberated. Once the starch explodes, the pasta swells and softens, and the water turns foamy. After the pasta is strained, this foaming, whitish water is typically spilled into the kitchen sink. However, experts suggest that the pasta water shouldn’t be discarded like that. 

The strained water is more precious than cooks might ever realize. In a September 2023 post, the American cooking magazine Cook’s Illustrated (@cooksillustrated) elaborated on why you should never throw your pasta water away. “Keep a stash of pasta water,” the post says, alongside an illustration of water being poured from a cup into the grooves of an ice tray. Taking the instance of J. McAuliffe from Grand Blanc, Michigan, the magazine explained that after boiling pasta, he “reduces the cooking water to concentrate the starch and then freezes the water into ice cubes.” The starchy ice, they explained, is “perfect for adding body to sauces and soups – and for the occasion when he forgets to reserve the pasta cooking water while preparing a pasta recipe.”

Hundreds of people found this hack useful and added their own tips in the comments section. “Ice also makes sauce smoother and less gritty if you’re blending,” said @xbansheeexx. @denisejoseph4 said, “Good for a carbonara reheat.” @rickographer, another user who resonated with this tip, commented, “Great idea! Half the time I throw out the pasta water, forgetting to save some and remember before it's too late.” Some others, however, pointed out the disadvantages and hassle of storing pasta water. Some said this water would be too salty, while some said it would take up too much space in the freezers. Many quipped that their family members or guests could mistake this frozen pasta water for a beverage and end up drinking it.

Jokes aside, the pasta water left over in the boiling pan is actually a resourceful ingredient to gelatinize those sauces, stews, and soups, according to 360 Italy Market. The website explains that starches are “complex polysaccharides” present naturally in the pasta granules. When these granules are tossed in boiling water, these starches experience a breakdown in a process called “gelatinization.” As the chains of starch molecules disintegrate, they release a deluge of glucose into the bubbling water. The glucose-rich water left over in the end can be re-used to thicken pasta sauces and envelop the granules in a sticky, silky glaze.

Chef Christopher Kimball also endorsed this idea while writing for the Associated Press. Sharing an excerpt from his book COOKish, he wrote, “Talk to the best cooks in Italy, and they’ll tell you the secret to great pasta is an ingredient many American cooks throw out — the starchy pasta cooking water. They always reserve a cup or two to stir into the skillet with al dente noodles to help the other ingredients adhere while thickening the sauce.” This, he said on Facebook, is the secret of the "creamiest pasta sauce."

You can follow Cook's Illustrated (@cooksillustrated) on Instagram for cooking tips.