Sal Cusumano fell down the wormhole a few years ago.

The third generation of South Jersey pizzeria owners on both sides, he saw the pizza world paying more attention to detail.

“I wanted to make my pizza better and I knew I had to start with the dough,” he said recently beside the conveyor oven of My Angelo’s Pizza in a Berlin shopping center, one of his family’s three shops. He talked to his food distributor in 2017: Any suggestions to make it lighter and less filling?

Gregorio Fierro showed up.

Fierro, a jovial, bear of a man, is a pizza consultant. Fierro, 58, has had a hand in some of the region’s best-regarded pizza formulas, including Angelo’s in South Philadelphia, the Pizza Brain shops in Kensington and Brewerytown, Acqua e Farina in Newtown, and Pizzeria Nonna in Mount Airy.

You want a puffier outer crust on your rounds? A Neapolitan that doesn’t sag in the middle? Fierro shows pizza-makers how to fix it. When a shop owner wants a pizza with certain characteristics, Fierro said he goes to work as “kind of like a culinary translator.”

“They start out wanting a few tips and then they start to see the quality of the product improve,” Fierro said. “And then it’s, ‘Well, I could do this even better.” Down the wormhole they go.

And with the $40 billion business showing no sign of slowing down — and with more home bakers making the move to open their own shops — there is plenty of business out there.

”It was kind of a life-changing moment,” said Cusumano, 38. “The one thing I love about Gregorio is he’s a straight-shooter. He’s going to tell you if he likes it, he’s going to tell you if he hates it. And for me, that’s the best kind of criticism. I want something raw. I want something real.”

Fierro has been cooking since he was a kid in South Philadelphia. Along the way, including years of kitchen time in Italy, he has gleaned a scientist’s background in dough-making — how flour, water, yeast, and sometimes sugar and oil can be transformed into dozens of pizza styles, given the right source of preparation, time, and heat.

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He travels to other cities to tinker, and he’s fluent in St. Louis, New Haven, Detroit, and Chicago. “There’s probably about 25 or 30 different American regional pizzas, not to mention a dozen or so in Italy. And then there’s world pizzas.”

In 2016, Fierro walked into the original Pizzeria Nonna in Germantown when Marvin Graaf was building it out and introduced himself. Graaf told Fierro what he wanted in a crust.

“I mean, it’s crazy,” Graaf said. “It’s almost like he looks through the dough and [decides] ‘this hydration percent, this type of flour, this type of maturation, this type of free ferment.’ But all of that aside, I’ve never met a nicer, more helpful guy. We started talking about pizza and became friends.”

Even some of the big mahoffs in Philly pizza — Danny DiGiampietro at Angelo’s in South Philadelphia included — seek Fierro’s counsel. DiGiampietro makes several styles of pizza, all with their own quirks. Fierro helps him manage.

“I went down the wormhole with Gregorio, too,” DiGiampietro said from his pizzeria, where he will on occasion throw away a day’s pizza dough that doesn’t meet his standards. (Most people overhearing a DiGiampietro-Fierro discussion on dough science just walk away, shaking their head.)

On his first day at My Angelo’s in Berlin, Fierro called out Cusumano’s stand-up mixer. It’s the same Hobart used to make dough in most corner pizzerias for the last 50 years. Fierro says it is more suited for pastry. He recommended upgrading to an Esmach, which Fierro considers the Ferrari of mixers, with a price tag starting at $12,000. It oxygenates the dough better and helps the ingredients incorporate more efficiently.

Then came a bigger challenge: changing My Angelo’s flour. “In Italian families, change is not something that’s welcome,” Cusumano said. “We’ve used Pillsbury my whole life, you know, and to tell my dad that we‘re switching off of Pillsbury — that was a tough conversation. But that was Gregorio bringing something that he saw inside of me and telling me it’s OK to do something different.” He managed to convince his father, Anthony, to use better flour.

Cusumano’s next project for Fierro is settling on formulas for the pizza dough at a shop he is planning to open in late 2021 or early 2022 at 872 Haddon Ave. in Collingswood.

Cusumano said the pizza will be nothing like the New York-style he is accustomed to serving.

“There was something inside me that I wanted to do — something with pizza, but something that no one else is doing,” Cusumano said. “I feel like from my first conversation with Gregorio, I think he saw that in me. I really want to do this because it’s my passion and I want to share it with those who share that same passion. This is for me.”

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‘I always loved pizza’

Fierro, the son of Italian immigrants, is a dual-national straddling two worlds. There’s the South Philly of both his youth at Ninth and Moore and his adulthood in Pennsport (he’s a married father of two girls whose younger one cheekily addresses him as “Doughboy”). There is also the Italy of his college years and current business travels.

“I always used food to make money while I was in school,” he said. “But I never really wanted to cook professionally, even though I had a proclivity for it. I just didn’t know if I wanted the lifestyle. But I had to make a living and Lord knows there’s not a lot of money in the art history game.” He leads art tours of Florence for fun.

Back in the United States in the early 1990s, Fierro produced food-related television shows and was a culinary instructor. Eight years ago, he got a job as a corporate chef for a small food distributor and joined Le 5 Staglione, Italy’s largest flour maker, as a corporate chef. His consulting work is freelance, he insists.

That’s when Fierro fell into the wormhole.

“I always loved pizza,” he said. “Working in that environment really forced me to go back and study it carefully. Once you start playing with it, it becomes an obsession. I went overseas, I worked with chefs. I went to competitions and I just got in deeper and deeper. As I realized I was amassing all this knowledge, I also realized there were a lot of people who were really interested in it. ... Pizza is getting bigger every day, and the desire to make better pizza is getting bigger everyday.”

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Nish Patel brought in Fierro a year after he bought Del Rossi’s Cheesesteak Co. in Northern Liberties. In March 2021, Fierro “walked in, threw our recipe in the trash, and gave us better tools to work with,” Patel said. Fierro suggested aging the dough, then pre-fermenting the dough — and mixing Italian 00 flour as well as King Arthur. Business is up and Patel is delighted with the quality.

Chains hold no interest to Fierro. “I don’t like what they do,” Fierro said. “I want [their pizza] to continue to suck. I want great pizza places that are owned by individuals and [lousy] chains. That’s what I’m going to keep working on until God takes the power from my hands.”

Want a pizza recipe?

Gregorio Fierro offers this recipe, which should yield six 12-inch pizzas. Remember that baking is a lot of science, so weigh and measure everything. Fierro said doing fine pizza at home is a challenge because many ovens can’t reach 500 degrees reliably. He suggests turning on the oven at least 30 minutes before baking. Also, for best results use a pizza stone and pizza steel. Put the stone near the broiler, turn on the broiler, and let it heat for 5 minutes before you slide the pizza onto the steel for baking.

Gregorio Fierro’s Pizza Dough

1 kilogram bread flour

650 grams (ml) water at 50 to 55 degrees

5 grams instant dry yeast (available at Sam’s/BJ’s type stores or online)

25 grams sugar

25 grams salt

20 grams oil (extra-virgin olive oil is best)

Combine flour, water, yeast, and sugar, reserving 5% (about 1/4 cup) of the water, in a mixer. Mix for 4-5 minutes, then add salt and remainder of water. Mix until smooth and dough is strong (it shouldn’t easily break when you pull at it, maybe 10 minutes in a home mixer). Continue mixing and add oil in a slow stream until incorporated into dough.

Let rest, covered, for 30-60 minutes, or until volume increases by about 30%, then put into covered container and refrigerate for 24 hours.

Ball to desired dough weight (for a 12-inch pizza for home, about 275 grams). Make the dough balls tight, round, and smooth.

Let rest, covered, at room temperature for 4-6 hours, shape into pan, and top.

Bake at 500 degrees for about 6 minutes.