More than a year in the making, a print project takes Science to the streets. 16 months, 53 restaurants and 7.235 kg of xiao long bao later…

A recent Monday evening at Zun Ke Lai, a xiao long bao specialist in Xuhui:Me, to cashier: "Hi, I’d like four baskets of pork xiao long bao."Cashier, to me: "Oh, uh. We’re off work, we don’t have any more. Xia ban le."Me, to cashier, seed of frustration: "Doesn’t it say 10am-10pm on your window?""Yes. But we stop xiao long bao at 8.30.""Oh, it’s ok then, it’s only 8.24.""Ehhh…"Chef, leaning next to the cashier on a work table, staring at his phone, to me: "We’re sold out. We don’t have any more. Mai guang le."Me, to both: "But she just told me that you don’t have them because you’re off work, not that you’re sold out."Cashier: "We’re off work. Xia ban le. Order something else."Me, again: "So which one is it? You’re off work or you’re sold out?"Cashier and chef at the same time: "Off work. Xia ban le” / “Sold out. Mai guang le."Cashier and chef turn to each other with the ‘oh fuck, why’d you do that’ look.Me: "Aha. So you’re not actually sold out, you just don’t want to make any more, right? That’s it, you don’t want to make any more?"Cashier: "Sold out."ARGH. Wo cao.Well-meaning customer sidles up next to me, trying to play ‘let’s help the foreigner’. The whole conversation up to this point has been in Chinese.Customer, to cashier, in Chinese: "What’s going on?"Cashier, in Chinese to customer: "He’s trying to order xiao long bao but we’re off work. We’re off work at 8.30."Customer turns to me, in Chinese: "She said they are off work."Me, to customer, in Chinese: "Yes, I understand that. We are all speaking in Chinese. But that’s not the problem. The problem is that she says they are off work, he says they are sold out" -- point to chef slumped over his phone -- "and I can tell they just don’t want to make them."Customer, to cashier: "He says…"Cashier: "We’re sold out. Mai guang le."Customer, shaking his head at me: “They are sold out. You know, this isn’t like McDonald’s, where they have everything you order whenever you want. It’s not like that. It’s not McDonald’s. They have to make the filling in the morni—“Me, to him, frustrated again: "Yes, yes, I know how they make xiao long bao! I’ve been writing this Index for more than a year, I’ve been to 53 places for xiao long bao, I was a chef -- I KNOW HOW THEY MAKE THEM! That’s not the problem! The problem is they don’t care, they just want to get off work. So they say they are sold out. I’ve spent 30 minutes getting here tonight, I made a special trip for the xiao long bao. I—"Customer, to cashier: "He says—"Cashier, to customer: "Xia ban le!! Off work!!"Customer, turns to me and smiles: "Mai guang le. They are sold out."I didn’t get my xiao long bao. Instead I stormed out in a China tantrum, swearing to myself that they were done, I was taking Zun Ke Lai out of The Index, I’d just delete them, no one would know the difference, I don’t care if they are the best xiao long bao engineers in this entire city…But this is Science. Deep breath. Another. Good. One more…I’ve spent the last 16 months roaming Shanghai, dissecting xiao long bao one shop at a time, one dumpling at a time, to create. It is, to quote myself, “a quantitative interpretation of the colloquial standards for a well-constructed soup dumpling”, based on what many Shanghainese will tell you makes a good one: thin wrapper, plentiful soup, abundant filling, fresh meat. 皮博, 汁多, 馅大, 肉鲜.I have taken a digital scale that measures to a hundredth of a gram, digital calipers that measure to a hundredth of a millimeter and hair scissors to more than 50 restaurants, shops and grotty holes in the wall, to measure: the exact quantity of soup and filling; the weight of the entire dumpling; and the thickness of the wrapper.I’ve then plugged the results into a self-made formula based on the ratio of filling to thinness of wrapper, and used the score to create The Index. The Index is then divided into three classes; Class A is the best. As I said, Science.Xiao long bao can basically be considered an engineering challenge. At their soupy core, they are a physics compromise between tensile strength (the wrapper breaking) and pressure exerted by a mass / density (the filling). Some argue that thick dumpling skin is a “style” all its own. A lot of Shanghainese diners I met along the way emphasized that the wrapper was just that -- a way to get a soupy meatball into your mouth. As such, its flavor should be minimized. In this theory, the primary offender is the “head” of the dumpling, where the folds bunch up and create a topknot. These folds stack up, exponentially growing the topknot. They are the major obstacle. Ergo, in order to get the smallest “head” you need a thin wrapper. I suppose you could just not eat the head, but…Out of the 52 restaurants, 18 made it into Classes A and B. The others were disqualified for other scientific reasons: breaking, too much MSG, I didn’t like them.You probably want to know who has the best xiao long bao in Shanghai. Shut up with this science talk. Where do I? Well… Zun Ke Lai is at the top of The Index (score: 24.32), followed by Taibei Mingchu (18.52), Jade Garden (17.96), and Ding Xin Di (for now, a single restaurant in its market testing phase, jointly founded by an old dim sum chef from the State Guest House; 16.42). There are nine others in Class A, and that’s the way to read The Index. While there are differences, restaurants in the same class are more similar than they are different, and at the very top of the pile (those with wrappers consistently below 1.10mm), that difference is slight.The Index is intended to be a completely objective measure. It’s hardly a major restaurant project, but it does sit on the same spectrum as Ultraviolet . With that, Paul Pairet is trying to turn the subjective up as loud as it will go. The whole theater of Ultraviolet is based on that idea – exaggerating your environment to influence your taste. At the other end sits me, with six empty xiao long bao and a scale sticky with spilled pork soup. I don’t want to exaggerate your environment. I want to eliminate it. Xintiandi or a cave in Tora Bora. It doesn’t matter. Show me your dumpling. That’s all I need to know.There is the matter of taste. If you want to know if Jia Jia Tang Bao or Din Tai Fung is better, it’s there, at least in terms of engineering. Measuring the fourth colloquial standard -- the freshness of the pork -- would have required potentiometric solid-state electrodes or near-infrared spectroscopy. I’m just one guy. I do not have a near-infrared spectrometer and neither do any of my WeChat friends.The best I can tell you is that there are two basic camps: those who prefer a milder filling and those who prefer a strongly pork-flavored filling. Din Tai Fung is the former. Fuchun is the best example of the latter. Beneath that, there are variations in the amount of sugar and MSG used to season the pork, whether the filling includes spring onion, ginger or Shaoxing wine, and how finely the pork is ground (and thus how dense the meatball is).This also pre-supposes two things: you are in the Nanxiang xiao long bao realm, and not the Suzhou or Wuxi world (there are hundreds of these shops in Shanghai), where the dumplings are about 50% bigger and the filling is seasoned heavily with sugar and soy sauce; and you’re paying attention to the single most important factor, whether the dumplings are served immediately after steaming (which is why a place with average dumplings that makes them to order, or at least in a constant rotation that matches the customer flow, will outclass a good one who lets them sit), or whether they’ve been either cooled or over steamed. Someone should make a ridiculous printed publication, available with cash payment on delivery, detailing all of this stuff…What The Index doesn’t say, in fact what it’s explicitly designed not to say, is that these variations are the human factor, and it’s people behind the dumplings and the dumpling shops, and people are interesting. Over the course of 18 months, I heard the story of Jia Jia Tang Bao, which sprung out of a family that had a very noble, wealthy upbringing but lost it all during the Cultural Revolution.Down and out, they turned back to memories of the dim sum of their childhood, made by the house cooks, and planted those memories in a (now closed) six square meter shop on the edge of the Old Town. It’s the second generation running things now (hence the exact same dumplings and process at Lin Long Fang , the #2’s own brand), and the dumpling business is good. A lot of the family has moved to Chicago, and Jia Jia may spring up there one day too.There’s the story of the Hongkou stragglers, and why there are so many xiao long bao specialists in that district -- the district government’s F&B arm gathered up or helped start a large network of “independent” operators way back when, though it was the government behind them all, pulling the strings. As the planned economy fell away, the operators struggled along on their own. In the past five years, rising rents have put most out of business, though a few are still clinging on. At You Yi Cun , a tough Ayi in her 50s, assigned to the shop 20 years ago but now a partial owner, is still kicking. And making kick-ass pot stickers, in addition to her xiao long bao.There is the mystery of Fu De, whose dumplings are just not good, but whose wall has a faded sign with addresses for its “other” stores. Addresses that turn out to belong to other now-unrelated shops, like Wan Shou Zhai , which Shanghainese flock to. Bothering Wan Shou Zhai’s Ayi-in-Chief one day, who has been there for 30 years, before they even added their small-sized xiao long bao to the menu, I baited her with a question about Din Tai Fung. “Never heard of them,” she stonewalled.I made the obligatory visit to Cheng Huang Miao, the Temple of the City God, at Yu Garden , to stand in the ground-floor take-out line for 43 minutes. It is undoubtedly a tourist factory, but watching the factory workers assemble an entire steamer basket’s worth of dumplings in about 30 seconds is still fun. I trekked up to the third floor, which operates under the same name. It might as well be a completely different restaurant; it’s where they hide the decent xiao long bao, though there’s a 50rmb minimum to keep the riff-raff out. (The second floor is standing room only, and the dumplings are in between in both quality and price.) Back downstairs, out of the mob, dutifully taking my dumplings from the hole in the plastic window, I started to enjoy them. Not as xiao long bao -- these are the thickest wrappers in Shanghai by far; the presence of soup is not a given -- but as just doughy pork dumplings.Zun Ke Lai had the thinnest average wrapper in Shanghai at 0.72mm. Thinner than Jia Jia Tang Bao, Paradise Dynasty , Din Tai Fung. (In a twist, a knock-off Din Tai Fung in Gubei had thinner wrappers than the actual Din Tai Fung.)The ratio of soup, meat and wrapper was in the golden range. I couldn’t just take Zun Ke Lai out. Even if the short auntie who is in charge of the xiao long bao is a master roller (the rest of the staff leave something to be desired). Even though she now rolls her eyes when I walk in, because of the time I ordered 54 xiao long bao for myself and then measured them in sets of three every five minutes, for an hour. (Result: After 10 minutes, the wrapper absorbs soup and residual steam vapor, swelling by 25%. After 40 minutes, it’s 55% thicker than a fresh one.)I calmed down and left them in The Index. There are still there, at the top of the pile, home to this city’s premier xiao long bao engineer and a couple of frustrating service staff. But what can I do? Science trumps Ego.***