An outsider might conclude there's a lot of partying going on in an employees-only floor at the Bellagio. There's no bar in sight but still the place smells like booze.

“You smell that?” asks Jill Niehoff, the Bellagio’s assistant beverage manager.

It’s hard not to. Inch closer to a pair of double doors across the hall from the resort’s carpentry office, and the alcohol aroma grows stronger. Peek through a pair of windows and you find the source.

This is the Bellagio's pump room, the hub of the resort’s beverage operation, where almost 2,000 upside-down liquor bottles stand at the ready on metal racks, like troops marching in tight formation. The apparatus looks like a veiny machine out of a low-budget science-fiction flick.

Liquids continuously feed into multiple mouths of a complex system of plastic tubes and spring pumps. When a bartender from one of the property's 53 drink stations triggers the system to zip a shot to a waiting glass, it sounds like an airlock from Star Wars. Bottles burp with bubbles.

A similar room powers drink nozzles at Aria, and resort executives hope to replicate the operation at all their properties. The self-sufficicent system, which only requires the occasional porter to restock, costs $250,000 to install.

Each station connects to 48 brands of liquor back at the pump room. Each brand gets its own tube, which feeds to a series of valves anchored to the wall. That's where the liquor then branches off into a series of other tubes running through the walls to all the property's bars and restaurants.

That's why, in all, the pump room's tubing stretches 90 miles, the distance from Las Vegas to Laughlin, or Key West to Cuba.

Behind the bar, bartenders used a buttoned pad -- flush with 58 buttons -- to call up multiple pour sizes and 144 pre-programmed cocktails, some containing up to five liquors.

When a bartender pulls out her beverage gun and pushes the button for, say, Drambuie, a wall-mounted spring pump triggers an air compressor tucked in a corner of the room. A shot of air pushes a pre-measured dose of liqueur shoots through those tubes hidden in the walls. Those tubes converge into the beverage guns under the bar, out of sight, delivering the shot into a glass.

Though made of clear plastic, the tubes change color when filled with booze — from faded yellow (tequila) to dark brown (Kahlua).

Depending on the bar’s location in the casino, the alcohol travels between 1,000 and 10,000 feet before it hits a glass.

Stored in boxes instead of bottles, mixers such as Sprite, ginger ale and tonic water are sent to bars in the same manner.

About 40 bartenders on every shift dispense an average of 67 shots each. The pump room limits waste by pouring perfectly measured shots.

The pump room holds up to 1,800 bottles of vodka, gin, rum, tequila, cordials, bourbon, scotch and whiskey. The only exception: Bailey’s Irish Crème. The liquor is too thick to pass through the tubes.

Designed by Las Vegas liquor management company Easy Bar, the pump room requires little maintenance. Because germs can’t survive in alcohol, the tubes stay clean. If there’s a leak, a technician can make surgical repairs.

Outside of the machine’s daily bustle, there’s not much activity in the room. The system is self-sufficient and controlled by a computer. A porter has to visit every shift to make sure there are no empty bottles, but that’s rare, since the tubes feed from several bottles of the same brand at all times.

The scores of upside-down bottles and tubes have prompted some to call the room Bellagio’s “intensive care unit.”

But infrequent visitors have to be careful. This is a place where it’s always bottom’s up.

“The vapors go right into your pores,” Nieoff says. “You get hungover without the fun part of drinking it.”.

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By the numbers

$250,000: The average cost to install a pump room in a casino resort

1,800: The number of bottles Bellagio's pump room can hold

90: The number of miles of drink tubing that runs through Bellagio

26: The number of miles of drink tubing at Aria

53: The number of bars at Bellagio

67: The average number of shots Bellagio bartenders serve per shift