There are many paths into the restaurant business. Townsend "Tod" Wentz became a chef after escaping the grind of a science career. After nearly 20 years of working for others, he took the solo plunge in April 2014, opening the French-inspired Townsend on East Passyunk Avenue and, later, the Italian BYOB A Mano on Fairmount Avenue. Along the way, he amassed a crew of dedicated workers, including his wife, sommelier Gordana Kostovski; manager Lauren Harris; and chefs Colin Leary and Michael Millon.

With a third restaurant, a Spanish tapas specialist called Oloroso, scheduled to open in October at 1121 Walnut St., he sat down to talk business.

You have two science degrees?

The first one was in chemistry. When I left school, I was an analytical chemist for a year. I hated working in a lab by myself under a hood, doing food science. I was doing work on canola oil, reworking some of the tests for acids in canola that would make it go rancid. It was very slow work, and then at night I would go and cook, and it was busy and boisterous and involved. I liked that so much more. I got into another lab at Penn doing some work on a congenital lung defect in twins. I wanted to do some recombinant DNA research, so I went back and was going to go to graduate school for that. But I had to clean up some stuff to get into the biology program, so I got a biology undergrad and I did some biology grad classes for my degree. Three months after that is when I [worked] at the Four Seasons.

That changed everything?

I'd been at this high-volume restaurant next door [Dock Street, then at Two Logan Square]. I've been cooking in and out of these little kitchens and I knew food, but I didn't know. I was reasonably capable and competent, but I was doing what I could do and what I had seen, but I had never seen anything like that.

How did you make the leap from chef to restaurateur?

I learned a lot at Lacroix at the Rittenhouse about numbers management. I would often help chef [Jean-Marie] Lacroix substantiate our costs, because it was costly. … It just got to the point where I was getting up into my mid-40s. It was like, if I'm not going to do my own thing now, when am I going to? When am I going to take that shot after working for 18 years of learning and helping other people fix their restaurants?  When am I going to figure out what it is I want to do, and what I want to say, and what kind of restaurant I want to operate in? So we started looking. I knew I didn't want to take on partners, either from a debt standpoint or from sharing decision-making processes. I wanted to do the design. I wanted to do the feel, the music, the drinks. I want to get the person whom I trust to pair a wine with the food. I want to do the food I want to do, and I was willing to start small and reinvest in our vision and what we were trying to accomplish. We came across this space when they were starting to have some challenges.

Three weeks before we signed the lease here, we signed the lease for what became A Mano — two years of pain and suffering at the hands of zoning, L&I, you name it, later.

Did you bootstrap?

Both restaurants. I saved, I borrowed money from my sisters and my parents. [Gordana] and I put up everything we had, retirement accounts, which wasn't substantial, but whatever we had, we used. Lauren and Colin painted this. We didn't take salaries for three months. I paid them back. Lauren varnished this floor. I taught her how to varnish. I did the upholstery, sprayed the chairs, built the bar, built the back bar, did the lighting design, bought the lighting, had it installed.

How did you know it was going to work?

Is there anybody who opens a restaurant who knows it's going to work? Because if there is, I want to meet him. If you're not supremely confident in what you're doing, or a gambler, do not open a restaurant.

Did you have a plan B?

Yes. Carry a clipboard for Aramark. You either win or you lose. That's it. We worked as if, and we still do, as if it is the end of the world if we don't satisfy every guest. We can't be perfect all the time, but we work very hard to make sure that we deliver at least what we say we're going to deliver or more. The choice is, you don't deliver and you're a failure. That's it and it's every day, all the time.

When did you realize that this was going to be successful?

Before we got reviewed, we spent a long, lonely summer standing on the sidewalk saying hello to everybody that walked by. Then the reviews started coming; we started going from doing seven to 10 and 15 covers to 40 covers and the feedback was phenomenal. We just worked really hard, and I made the food that I loved making and wanted to make from when I first started cooking French food. Then we took everything that we made here for the first year and a half and poured it into A Mano.

That was a coup, getting Michael to work for you.

I promised Michael, "Come back to Philly from New York. Leave this A Voce job running this one-Michelin-star Italian, this big high-profile restaurant. Come down here and we're going to open up a second restaurant in a year, Italian BYO, and you be the chef. I'll help you, give you everything you need to run the menu that you want to do, and you'll have creative control with oversight." He's off and running, and he is making some of the most interesting Italian in Philly, and I couldn't be prouder.

What prompted the opening of Oloroso?

I always wanted to do a kind of a really rustic Spanish tapas because it's what I love to eat. I have a lot of different and varied tastes. French is technique-driven and, yes, relies on good ingredients as well, but Italian is very ingredient-driven and peak-of-seasonal freshness is critical to the flavor of a lot of the ingredients. Spanish is a cool version, in my mind, of that, where you can take rustica and seasonal, and just traditions that are different than France and different than in Italy but with similar ingredients, and make a completely different cuisine. I love that. Oloroso will be rustic, organic, sun-drenched, smoky, with a wood-fired oven grill, which is really why I took that spot. We have got a ton of fun stuff lined up.

Did you go on a scouting trip to Spain or …

A lot of New York. We were going to do a crash course in going to Spain this summer and then we got the space and I was like, "No time, guys. We're not going."

If your 16-year-old daughter said to you, "Daddy, I want to go in the restaurant business," what would you say to her?

"I hope you like working all the time."

Your favorite cuisine?

Japanese, because I can't make it.

What do you like to cook at home?

We made stuffed cabbage. It was delicious. And it wouldn't really fit at Townsend or A Mano. I remember I said, "If we can find a place for this somewhere, we're going to put this on the menu. This is freaking delicious."

What is the hardest part about being a restaurateur?

The plumbing, hands-down. I know more about plumbing than I ever thought I would know. That's an absolute fact.

Are there too many restaurants in Philadelphia right now?

They open, they close. Is there too much churn? Is it becoming too competitive?  It might be competitive for people who didn't expect it to be 24 hours a day for forever, but are there too many? Are weaker places closing and you're winding up with a higher and higher caliber of restaurant? That's absolutely happening. That's absolutely happening.