This past New Year's Eve, I hosted a pasta party. It was exactly what it sounds like: me, cooking more noodle courses than my three guests could possibly eat in the hours we spent huddled around my kitchen table, and quite a bit of Parmesan.
As the evening progressed, my stock of reserved pasta water grew as murky and expansive as my guests' conversation (blame our local liquor store's sale on sparkling wine). Some amount of bucatini all'Amatriciana, rigatoni with fresh basil pesto, and aglio e olio e salsicccia later, I found myself with a full jar of the starchy stuff.
Pasta cooking water has long been touted for its abilities to emulsify, thicken, and facilitate binding between noodles and sauce. So when I make pasta of any sort, I prefer to remove the noodles from the pot with tongs or a spider, and reserve at least a few cups of the liquid to incorporate into the sauce as needed. (For something like pesto, this might mean tossing the rigatoni and sauce with a few tablespoons of it; for a dish like aglio e olio, the reserved water would actually serve as the basis for the sauce.)
But it wasn't until New Year's Day that a funny little trick came into play.
We woke on Jan. 1 with with enough leftovers to feed us for much of the year to come. And it became clear, quickly, that our first dinner of 2019 would be another pasta party. I tasked my little sister with grating more cheese, and I set about reheating the remains, each batch of noodles already tossed with sauce from the night prior. That's when I saw it: a jar of something questionable and turbid, cloudy and faintly tawny. Reserved pasta water! Somehow, my stockpile had made it into the fridge at the end of the night.
It turns out, pasta water works just as well to animate leftover noodles in sauce as it does to bring the two together in the first place. I added generous splashes to each saucepan of noodles and stirred, watching as dried out, near-ossified pieces of rigatoni with clumps of congealed cheese turned back into a creamy, pesto-y affair. The starchy liquid—plus a little extra salt—brought new life to aglio e olio, and roused sedentary bucatini all'Amatriciana to its earlier glory.
Which made our first pasta party of 2019 quite the success.