Once upon a time, New York City was full of siphon-bottle seltzer plants. Thousands of deliverymen lugged cases of the fizzy stuff around the Lower East Side’s narrow streets; egg creams were everywhere; and the Marx Brothers squirted each other in the eye. It’s no wonder we waxed lyrical about seltzer in Tablet’s highly selective list of 100 Jewish Foods.Today, for better and for worse, supermarkets and SodaStream have done a number on seltzer. But the old-school spray bottle hasn’t gone the way of the dodo entirely. NYC’s last seltzer factory, Brooklyn Seltzer Boys (formerly Gomberg Seltzer Works) in Canarsie, is keeping the tradition alive.Established in 1953 by Moe Gomberg, this fourth-generation business is one of only three or four old-school seltzer bottlers in the country. Back in the day, Moe worked with a co-op of seltzer men, all with their own bottles, who shared the plant. Like milkmen, they had established routes and trucked their wares throughout the boroughs. Today, the company delivers to restaurants, hipster craft and cocktail bars, offices, and nostalgic individuals willing to pay $40 to $100 a month for home delivery of what they see as a truly superior product drenched in glorious, sepia-toned memories. It’s a bubbly, fizzy madeleine.I went on a tour of the factory with New York Adventure Club, which you may recall was also my ticket into the ruins of Ellis Island’s abandoned, crumbling hospital complex. After an hour-long subway ride from Manhattan, we were greeted by Alex Gomberg, the company’s 30-year-old fourth-generation representative who’s spearheading the company’s new wistfulness-tapping brand identity.In an old-school factory setting of cement floors, cinder block walls, and dusty crates of topless old bottles stacked to the ceiling, Alex told us of the joys of seltzer. “It’s a cleaner, crisper-tasting water because it’s triple filtered,” he said. The siphon mechanism means the seltzer won’t lose its fizz for months, even years. “A bottle from the supermarket loses pressure the minute you open it,” he says. “It’s flat in days.” And of course, real seltzer bubbles aren’t your passive, wimpy little supermarket bubbles; they’re big and assertive, like Brooklyn. “You really feel it when it hits your throat,” Alex said. “Good seltzer should hurt.”The seltzer-making process hasn’t changed much in generations. “It’s good old New York City tap water,” Alex noted, “filtered through charcoal, sand, and paper to take out solids and microscopic elements. It’s chilled to 42 degrees, mixed in a carbonator–we have a liquid C02 tank. We dial the gas up to 60 pounds of pressure; that’s a lot of pressure. You need a thick bottle.” We were surrounded by vintage 26-ounce bottles in shades of blue, green, and clear glass. “These are a quarter inch thick, thicker on the bottom than the sides, hand-blown in Czechoslovakia.” Alex passed around a bottle and we all peered at it, and surreptitiously lifted the bottles around us to study their bottoms. Yep. Etched in different styles and fonts, they all confirmed their birthplace. Which is, of course, like the LES of memory, a place that no longer exists.“We carbonate all the seltzer here,” Alex continued. “The liquid C02 comes in a big truck from Connecticut once a month. The truck parks outside, with a hookup. The pipes in here turn white and it snows inside in the summer.” The bottles are filled, six at a time, in a 100-year-old machine with “The New Monitor Syphon Filler, Barnett & Foster Engineers, London” carved in a bold font on the front plate.Every bottle has its own story. One says Bushwick Bottle Works. Another says Vincent Lopopolo, 2357 E 19th St, Brooklyn NY. There’s FIZZ. Ben’s. A-1 Sparkling Seltzer. Some have old phone numbers, with the letter prefixes. “We don’t want to put a sticker over the original writing,” Alex said. “These bottles are history. They’re hand-blown. The company names are etched in the glass. You knew this one was this guy’s bottle, this color, this route. When the guy sells his business to Joe, Joe now has his own and this guy’s bottles. Different generations didn’t make new bottles; they made their etching on the other side of the existing bottle. Then a new guy puts his name on the head [the metal top]. Then someone else does a sticker.” He grabbed a bottle. “Here, that’s Eli. I took over his route. He’s 80. I want to preserve the history and honor the seltzer men that started this business and kept it going.” Later, in the office, I saw a stack of rubber-banded index cards covered in addresses written in spindly old-man handwriting. Seeing me looking, Alex said, “Those were Eli’s.”Alex continued, “It’s a tough business. We schlep boxes up stairs. They can weigh 60 pounds. And they’re wide–a six-pack is a lot easier than a 10-pack.” Doorman and elevator buildings have made deliveries a lot easier, he noted. “But a lot of people just give me a key. I have a lot of keys.”The only Brooklyn Seltzer Boys branding, in a nice nostalgic font, is on the handmade wooden crates holding the boxes. “My dad was a carpenter and he builds them,” Alex said. The Brooklyn Seltzer Boys website notes that you can rent the boxes to hold centerpieces; Alex and company will also set up an old-fashioned egg cream station, with paper straws and your choice of syrup flavors, at your bar or bat mitzvah.In one corner of the factory, two young men (“our interns!”) were putting together seltzer bottle heads, cannibalizing working pieces–collars, washers, nozzles—from different dead heads. There are plenty of bottles in the world, but not enough functioning heads. “We have a two- or three-week wait list for new customers,” Alex said. “We constantly need to make more of these.” What about 3D printing? a tour-goer suggested. “Yeah, we tried that. It didn’t work so well,” Alex answered. Some newfangled things are great. Others are not. And time is a wheel. We may be, as NPR points out, entering a seltzer bubble. Consumption is up 42 percent over the last five years. Alex is onto something.It was time for a tasting. The seltzer was crisp and biting. But we all were really waiting for its magical transformation into egg creams. Which did not disappoint. “Fox’s U-bet is the only way to go,” Alex said. “It’s the best, and they’re a third-generation business. My daughter goes to nursery school with Kelly Fox’s daughter.” Alex discoursed upon the Bronx versus Brooklyn way to make an egg cream. The Bronx way is wrong. There is an instructional video on the website.The Brooklyn-style egg creams were divine, chilly and tickly and (in the case of the vanilla) just the right amount of sweet and creamy. For what it’s worth, though, anyone who tells you for sure where the name “egg cream” came from doesn’t know what they’re talking about. There are many stories. It’s like Talmud.The next factory tour is August 10th.