Pasta alla Cacio e Pepe, scientifically optimized

January 4, 2025 7:36 AM

A true Italian grandmother or a skilled home chef from Rome would never need a scientific recipe for Cacio and pepe, relying instead on instinct and years of experience. For everyone else, this guide offers a practical way to master the dish.

Phase behavior of Cacio and Pepe sauce [PDF], a scientific paper in which a team of pasta-loving physicists investigate the factors that contribute to successful (ie, non-separating) Cacio e Pepe sauce, and conclude by presenting a scientifically-optimized recipe to enable "consistently flawless execution of this classic dish."

The concentration of starch plays a crucial role in keeping the sauce creamy and smooth, without clumps or separation. If the starch content is less than 1% of the cheese weight, the sauce is prone to separating into unpleasant system-sized clumps corresponding to the “mozzarella phase” in Figures 1 and 2. On the other hand, exceeding 4% starch results in a sauce that becomes stiff and unappetizing as it cools. [...] The pasta water alone does not contain enough starch to stabilize the sauce effectively. As we already discussed, one could use pasta water “risottata”, i.e. boiled down to concentrate the starch, but the process offers little control over the final starch amount. A more precise and reliable method is to dissolve 4 grams of powdered starch (such as potato or corn starch) in 40 grams of water. ...

posted by Westringia F. (32 comments total)

A beautiful bsky thread from one of the authors on the process :)
posted by Westringia F. at 7:51 AM on January 4

Two (2) years ago, Brian Lagerstrom showed a cheater restaurant method (along with a more traditional method) that's bound to rustle some Italian jimmies. Not much science, just cookery.
posted by JustSayNoDawg at 7:53 AM on January 4 [4 favorites]

Lagerstrom’s recipe puts me in mind of this recent Slate article about how restaurants are ruining cacio e pepe by using butter or even heavy cream.
posted by jedicus at 7:57 AM on January 4 [3 favorites]

"...inspiring studies on its mechanical properties and structural behavior, pasta water (a mixture of starch and water) also exhibits interesting physical properties. These properties, which are central to both cooking and scientific exploration, include intriguing rheological phenomena and transitions such as non-Newtonian behavior and gelation [10]. Adding 1 part of water to 1.5–2 parts of corn starch is the most common way to get a non-newtonian fluid, sometimes called oobleck."

I spy a further-reading rabbit hole, but I'm far more interested in trying the recipe at the end of the article!

I'd never heard of this lovely peasant-style dish before. Thanks for posting!
posted by rabia.elizabeth at 8:00 AM on January 4 [1 favorite]

Adding 1 part of water to 1.5–2 parts of corn starch is the most common way to get a non-newtonian fluid, sometimes called oobleck

mmm, paste tastes good
posted by flabdablet at 8:06 AM on January 4

Cacio e Pepe is the hardest thing I've ever tried to make, and I have never mastered it. Maybe I will give it another go after reading this.
posted by maggiemaggie at 8:21 AM on January 4

I came across this recently: Cacio e Pepe Pizza Baked with Ice by Roman Pizza Maker Stefano Callegari
posted by ShooBoo at 8:23 AM on January 4 [1 favorite]

Years ago, at a restaurant in Manhattan that may not exist anymore named, um, "Cacio e Pepe," I ordered a Cacio e Pepe that they prepared tableside. I mostly remember that it involved an impossibly large block of Pecorino Romano that they'd dug a sort of bowl out of the top of, and that once the pasta was done, it (and probably a little olive oil and pepper) was dumped into this cheese-bowl and vigorously stirred until it was ready to plate.

That was impressive. And delicious. And very memorable.
posted by Navelgazer at 8:26 AM on January 4 [8 favorites]

paste tastes good

A standup comic once said, "Flour and water make paste. Flour and water and sugar make cake. So where does the paste go?"
posted by Lemkin at 8:28 AM on January 4 [6 favorites]

Maybe this article will get it through my thick head the importance of letting the pasta water cool down, also making sure the cheese is at room temperature. Seriously, cacio e pepe sounds so simple but so much depends on getting the temperature and proportions exactly right, or you just have a weird gluey blob of cheese.
posted by maggiemaggie at 8:34 AM on January 4 [2 favorites]

Botched by Babish ran into the sauce breaking continually so turned to Science! to get it right. The answer was a blender.
posted by fiercekitten at 8:38 AM on January 4

The answer was a blender

Isn't that the answer to a lot of Life's difficult problems?
posted by JustSayNoDawg at 9:05 AM on January 4 [2 favorites]

It turns out that Cacio e Pepe on 2nd Ave in Manhattan is still around, and I found a picture of the process in question!
posted by Navelgazer at 9:15 AM on January 4 [11 favorites]

This is an excellent BBC article on Cacio e Pepe, and the recipe at the bottom is the one I have saved to make this (though haven't done so yet). One aspect that is interesting here to me is the element of pecorino rind.

Anyway, I'm reminded of a funny thing I read somewhere, but unfortunately don't have a link for ... I probably saw on Twitter, back in the day: it was someone talking about Facebook comments on recipes, who said if you see a Greek recipe (with a lot of stuff not really authentic to the dish), the Greeks commenting will be like, "ah, yes, interesting, bravo, I'm sure you will enjoy that, blahblah!" but if you see an Italian recipe with non-authentic ingredients or techniques, Italian commenters will be like I WILL DIG UP YOUR DEAD MOTHER AND [terrible things]!!!. Lol!
posted by taz at 9:24 AM on January 4 [3 favorites]

A standup comic once said, "Flour and water make paste. Flour and water and sugar make cake. So where does the paste go?"

But flour and water makes delicious bread, if you're smart about it. And flour and water and sugar makes sweet bread, if you want.
posted by ssg at 9:31 AM on January 4 [1 favorite]

Devout Pastafarians need only refer to the Book of Noodles 14:3, where Saint Colander brings the Good News to the Romanos and Parmesans.
posted by panglos at 9:59 AM on January 4 [8 favorites]

This guy has a great version too.
posted by freakazoid at 10:34 AM on January 4 [1 favorite]

In this household we stopped following Colander with the Great Pecorino Schism of 1964.
posted by JoeZydeco at 10:42 AM on January 4 [4 favorites]

I enjoyed this ... but it's a paper with an all-male author list that thanks some women who "helped" in the acknowledgements. Bunch of physicists, checks out.
posted by Dashy at 10:44 AM on January 4 [6 favorites]

Sorry. Don't mean to be the party pooper. But, welcome to academia.
posted by Dashy at 10:48 AM on January 4 [3 favorites]

Using a minimum amount of water to cook the pasta with in the first place helps concentrate the starch, which along with not overheating the cheese gives me very consistent results. (I use a 12" skillet filled about halfway with water, spreading the pasts out and occasionally stirring so it doesn't stick together.)
posted by Greg_Ace at 11:30 AM on January 4 [5 favorites]

pokes head out of dish tank. "roughly 140° f."
posted by clavdivs at 3:03 PM on January 4 [1 favorite]

Get out of the dish tank clavdivs, we've told you more than than once you're not allowed to shower in there!
posted by Greg_Ace at 3:39 PM on January 4 [4 favorites]

Meh. I think the pendulum has swung too far in trying to scientifically perfect recipes. Cacio e pepe is supposed to be rustic and fleeting. I don’t want to add slimy cornstarch to it to get a more processed and perfect texture.

That said … I do have one tip, which is to stir stir stir very vigorously. That beats some more starch out of the pasta into the sauce.
posted by haptic_avenger at 7:22 PM on January 4 [2 favorites]

The NYT recipe for San Franciscohi style (Vietnamese-American) garlic noodles developed by Kenji Lopez-Alt calls for cooking the pasta in a wide and shallow frying pan with much, much higher ratio of pasta to water than you’d ever see an Italian recipe recommend. I will admit I initially bristled at the idea but was committed to trying the recipe as written and it totally works. The logic is that in restaurants tons and tons of pasta is repeatedly cooked in the same pot which results in concentration of leeched starch in the pasta water - you’re only cooking for yourself at home it will never get starchy enough to be useful, so by reducing the water you end up with a more concentrated starch base with which to build the sauce. Orthodoxy is overrated and science never/rarely fails.
posted by Exceptional_Hubris at 12:26 AM on January 5 [3 favorites]

The other day I made rice pudding with leftover takeout rice. Instead of just stirring in an egg at the end, I decided to try tempering the egg first. Made a huge difference to the taste. I'm going to try this with carbonara soon (I'm not a pepe fan).

Seems like the whole truck to the sauce is keeping the egg from cooking too fast. Tempering is much more reliable than trying to describe just the -right- trick of stirring and heat.
posted by Dashy at 5:21 AM on January 5

I can at least vouch for the pasta-cooking approach of “put dry pasta in pot, add juuuuuust enough water to cover, bring to a boil (stirring occasionally), then drop to a simmer until cooked through.” This also has the above-mentioned benefit of producing highly concentrated starchy pasta water for use in emulsifying sauces, as well as saving energy! (To save further time/energy you can use a lid to help bring it to a boil faster or while simmering, though if you’re bringing it to a boil covered you do really need to keep an eye on it because it’ll probably boil over instantly upon coming to a boil)
posted by DoctorFedora at 2:44 PM on January 5 [2 favorites]

“instinct and years of experience” is giving away the game; you don’t need years of experience to use an instinct. Experience is how you learn what signs of adequate starch in the water work for cacio e Pepe, though.

much, much higher ratio of pasta to water than you’d ever see an Italian recipe recommend

Histories of pasta IME explain it as a response to chronic fuel poverty around the Mediterranean. I can’t believe that boiling the largest possible pot of water was the approach at the time.
posted by clew at 3:24 PM on January 5 [1 favorite]

I came here to say what Greg_Ace said
posted by Jon_Evil at 5:07 PM on January 5

Tell clavdivs to get out of the dish tank, you mean? Don't bother, he never listens anyway.
posted by Greg_Ace at 9:27 PM on January 5 [1 favorite]

the vacation station
posted by clavdivs at 1:23 PM on January 6 [1 favorite]

The pasta water alone does not contain enough starch to stabilize the sauce effectively. As we already discussed, one could use pasta water “risottata”, i.e. boiled down to concentrate the starch, but the process offers little control over the final starch amount.

A little while ago, I had the idea that someone should be making standardized pasta water and selling it in grocery stores (maybe next to the cans & cartons of stock/broth?), just for the sake of consistency given how many variables there are in the process of boiling a pot of pasta. Perhaps you could even have a regular strength version that's supposed to imitate what a "normal" level of starchiness would be as well as an extra-strength version, which seems to be what these researchers have found works better for cacio e pepe.

Of course, the brand name of this pre-made, standardized pasta water should be "Reserved" in order to trick newbie cooks every time they see a recipe talk about "reserved pasta water".
posted by mhum at 3:10 PM on January 6 [3 favorites]