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The Mad Science of Gelato 

Inside Lush Gelato's flavor lab and the science of ice cream.

By Luke Tsai


On an exceedingly warm September afternoon in West Oakland, in the back room of a nondescript and soon-to-be-demolished warehouse, a new flavor is born.


The building itself sits in the kind of gritty industrial neighborhood where you'd expect to find an auto body shop or a carpet warehouse, not a production site for artisanal gelato. But that's precisely what Federico Murtagh, the co-owner and resident gelato master of Lush Gelato, has set up here. Murtagh's two small gelaterías, both his original shop on Piedmont Avenue and a more recently opened location in Berkeley's foodcentric Gourmet Ghetto, have built up a still-modest but devoted following among East Bay ice cream lovers, who praise the gelato for the impossible creaminess of its texture and the bold intensity of its flavors.


More recently, regulars have probably noticed the increasing inventiveness of the flavors themselves. While you can always get a scoop of vanilla or some kind of chocolate, the ever-changing daily menu of gelatos and sorbettos is now dotted with such exotic and unlikely options as Dijon Mustard or Star Anise or Black Garlic & Lime Leaves. Whenever possible, the ingredients are sourced locally, from the farmers' markets or other Bay Area vendors. Still, despite the playful flavor combinations and widely acknowledged quality of the product, Murtagh wonders if people really understand how much time and care goes into making a single batch. After all, he doesn't have the luxury of a big store that could show customers — through a little window, say — that day's gelato being churned right then and there.


"A lot of people probably think, I don't know, that we buy our ice cream from Ciao Bella or any of the other companies that are floating around out there," Murtagh said. "It's a pretty big disadvantage to make your own ice cream and not be able to show it. It probably looks like a restaurant that buys all its food from someone else and they heat it up in a microwave."


Indeed, for Murtagh, the process itself is the best part of his job — the long hours spent burning the midnight oil in his West Oakland flavor lab, where he's been known to stay as late as 3 a.m. tweaking some crazy new concoction until it tastes just right. "That's the fun part of it," he said.


As it turns out, the building that currently houses his production facility was recently purchased by a company that wants to knock it down and put in a new Kroger supermarket, so Murtagh is going to have to find new digs whether he wants to or not — preferably, he says, a retail space big enough for him to make his gelato on site.

In the meantime, his humble, subleased back room inside a West Oakland warehouse is where, as they say, the magic happens.


If you tell people that you make ice cream or gelato for a living, it's not unlikely that you'll inspire in their mind certain flights of whimsy — medieval alchemy with a dash of Roald Dahl: chocolate mixed and churned by a waterfall, whipped cream whipped by actual whips, and such.


The not-mundane-but-strikingly-different truth? Murtagh's workspace is all gleaming metal surfaces and everyone is decked out in hairnets and white lab coats, so the overall effect is less like a kitchen and more like a chemistry laboratory — albeit a somewhat primitive-looking one. (Citrus fruits are juiced using an old-fashioned hand juicer, and the machines that make the ice cream, however state-of-the-art they may be, look more vintage than space age.) And Murtagh's recipes themselves resemble simple mathematical formulas as much as anything else: no words, just a chart full of numbers listing the relative proportions of cream and sugar and egg yolk.


It follows, then, that the Argentinian-born Murtagh, scruffy and slightly sleepy-eyed from too many late nights on the job (cranking out as many as five or six new flavors a week), appears to see himself as more mad scientist than chef as he presides over the whole operation. Yet the vibe is a lot more casual than it sounds. Murtagh circulates throughout the room, fiddling a bit with the machinery. He stirs a tub of plum purée that he's doctored with wasabi powder, and tastes it. Not enough wasabi, he concludes. He gives some brief instructions to his two employees and to his business partner, Erik Jorgensen, who isn't involved in the gelatería's day-to-day operations but occasionally drops by the warehouse to lend a helping hand.


In the far corner of the flavor lab, there's a pasteurizer that mixes and cooks the gelato's custard base, which includes milk, cream, egg yolks, and, for today's flavor, the zest and juice from several oranges. And atop a small table, there's a sort of cauldron filled with chocolate that's being melted down and, next to that, a pot of hot coconut oil.

The main batch he's working on today, Murtagh explains, is going to be an orange gelato that'll have chunks of chocolate layered in. The twist will be to give the chocolate some heat by adding the coconut oil, which has been infused with some habañero peppers that he purchased earlier that day from the Happy Quail Farms stand at the San Francisco Ferry Building.


In the end, getting the final product to achieve that purity of flavor where you can really taste the essence of the plum or the orange is as much an art as it is a science. To start, Murtagh explains, you have to use a lot of whatever fresh ingredient you're featuring — no artificial additives. You have to understand how to create a balanced recipe so you don't throw off the texture or end up with something cloyingly sweet. But from there, he says, it's just trial and error, taste, taste, taste.


Likewise, at its beginnings, the process of inventing a new flavor combination is far from formulaic or sterile — more rap session than scientific equation. Anything might serve as inspiration: an unusual fruit Murtagh happens to sample, a dish he ate at a restaurant. Walking into the Cowgirl Creamery kiosk at the Ferry Building, Murtagh spots a display case full of blue cheese, which reminds him that he'd wanted to use that cheese as the basis for a new flavor. "I hate blue cheese, but ... " he says to Jorgenson, the thought trailing off. "So what do you think, blue cheese by itself?" And so everyone starts brainstorming: peppers and blue cheese? A classic pear and blue cheese combination? Roasted tomatoes and blue cheese? Of course any guy off the street can come up with an obscure flavor combination that sounds promising, but Murtagh's talent lies in making the stuff actually taste good. In fact, the gelato master welcomes customers who'd like to try their hand at some amateur flavorology of their own; they can submit an entry to the store's first ever Flavor Contest by October 8. The winner will have his or her flavor featured in the both Lush locations and receive a month's worth of free gelato to boot.


Back at the lab, Murtagh thinks the habañero chocolate mix might be ready. "Any brave tasters?" The chiles, he's heard, are 1,000 times spicier than a jalapeño, so he's been cautious with their application to start. Everyone dips a spoon into the pot and tastes. The chocolate is dark and rich, and the heat is subtle but creeps up in the back of your throat. After some discussion, Murtagh is convinced that he can go even spicier.

He reasons, "If you order orange habañero, you want a kick in the face, so that's what I'm going to give you." The name of the flavor will be Orange Picante.


Murtagh got into the gelato business by accident, he explains. In 2001, he came to the Bay Area from Argentina to work on a university degree. Along the way, he ended up meeting the owner of San Francisco's Tango Gelato, a fellow Argentinian whose ice cream maker was leaving for Europe. "They weren't doing very well in quality, so I said, 'Well, let me try,'" he said. "'I have no idea. I've never done this before, but you have nothing to lose.' It was kind of crazy to have no idea." Murtagh received some perfunctory training from the prior maker, but, really, he taught himself by reading up on the science of ice cream and getting in touch with some food chemists and pastry chefs. At the time, toward the end of 2004, Murtagh says Tango was using a kind of Italian powder chock full of ingredients that weren't particularly natural, as a big part of its gelato recipe. So he took it upon himself to find out the function of the various items in the powder so that he could replace them with more natural ingredients — replacing the emulsifiers with egg yolks, the powdered milk with actual milk, and so forth. The result was a product that came a lot closer to being made from scratch, and Murtagh realized that he had a knack for the thing. Eventually he parted ways with Tango to start his own company, Buenos Aires Gourmet, with financial backing from his father Jorge and, later, from Jorgensen. "I was an exchange student in Italy, which was where I started my love affair with gelato. And his was the best I'd ever tried," Jorgensen said. "He's super-dedicated, and he's got talent."


At first Murtagh just did wholesale contracts and farmers' markets, before eventually moving into the retail sector under the Lush brand name. Murtagh notes that Argentina has one of the world's largest Italian populations outside of Italy and, as a result, an absurdly high per-capita consumption of ice cream. And Argentine helado is much more closely linked to Italian gelato than the ice cream typically found in the United States. In Argentina, Murtagh explains, gelaterias are kind of like US pizza places. "We have ice cream stores that deliver ice cream, like pizza delivery or something like that," he said. "They have these little scooters and deliver it in a styrofoam container. I remember at some point before coming here, every Sunday I would order a kilo and finish a kilo in one day." In that sense, Murtagh really does have gelato in his blood, although at Lush, the Argentinian influence is limited to certain specialty flavors that the shop carries on and off, like Yerba Mate or Dulce de Leche. But aside from his sorbettos, which contain no dairy products, all of his creations can certainly be classified as gelatos and not ice cream. The basic difference, Murtagh said, is that gelato has much lower butterfat content than a so-called "super-premium" ice cream like, say, Häagen Dazs. This is somewhat counterintuitive, since most people tend to assume that the decadent creaminess of a good gelato must come from adding a lot of fat. Actually, the other key is to have a very low "overrun" — i.e., the amount of air whipped into the mix when churning it. This makes a gelato or ice cream denser and creamier and less prone to iciness. The maximum overrun for super-premium ice creams is 30 percent air to volume ratio — Murtagh speculates that the overrun of a typical Häagen Dazs ice cream is at least 13 percent, whereas gelatos are under 10 percent. What you're going for, he says, is a super smooth texture and intense flavors. Murtagh adds that to enjoy gelato at its ideal texture, it's also important to store it at a low temperature. "A lot of gelaterias serve at a kind of higher temperature, kind of semi-melted," he says. "What that does, in part, is it hides imperfections of the product." After all, he explains, if the gelato is already half on its way to becoming a puddle by the time you eat it, the only thing you'll be able to appreciate is the taste, not the texture.


Finally, when Murtagh says he makes his gelato from scratch, he really means from scratch. Unlike many other high-end ice cream and gelato shops, Murtagh makes his own custard base — the blend of egg yolks, cream, and other ingredients that forms the foundation for a batch of gelato before it gets churned and frozen. Many of the other shops use pre-made mixes — the one made by Straus Family Creamery is most popular among the high-end places in the Bay Area — that may or may not then be doctored with fresh cream and other additions. The only ingredient Murtagh uses that isn't 100 percent "fresh" is the egg yolks, which he buys pre-frozen and pasteurized for safety reasons. It's the mix that Murtagh credits with getting the texture of his gelatos exactly right.

As Jorgensen puts it, "This is really what separates us from the rest of the world."

But the proof, as they say, is in the pudding — or in that deceptively generous single scoop which, if your willpower is strong enough, you can savor for a solid fifteen minutes with hardly a trace of meltage. The gelato at Lush is about as good as any you'll ever try. Taste, texture, a dash of whimsy if you like (or just plain vanilla, if not) — the whole nine yards. And the flavors — whether for something as ordinary as coffee or as odd as cilantro — really do ring true.


"Yes, that's cilantro," you'll say to yourself. "Yes, that's the essence of a peach."

Or, if you're in the mood for a good old-fashioned kick in the face, you might even consider the Orange Picante.


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