It's 3 a.m., and while there may be a phone ringing at the White House, there are also a lot of other things going on. Taking our cue from Sen. Hillary Clinton's earlier political ads, the PG continues its occasional series looking at what kinds of jobs folks are doing at 3 a.m. Today we go to the Penn Brewery at the foot of Troy Hill.

On a night so humid you could wring the air out like a wet dish towel, it doesn't seem to matter that the door is propped open and there are two fans whirring -- Nick Rosich is hot.

Dressed in a yellow T-shirt and khaki shorts, his face glistening with sweat, he slides open the small door of the giant copper kettle and plunges a long wooden stick into the bubbling liquid.

On his right calf is a tattoo of Kermit the Frog with red dragons on either side of it.

He brings the stick up to look at its markings. The liquid is not quite up to the desired 35 hectoliter mark. He closes the kettle door.

Now it's time to check the yeast because in beer brewing, that's what it's all about -- yeast.

There's always a little something to do here and there at the Penn Brewery and in the wee hours of a recent Friday morning, Rosich is the one doing it.

The Chicago-born brewer who moved to New Castle at age 10, is the lone man on duty during an overnight beer-making shift. However, unlike the Maytag repairman, there is plenty to keep him busy.

His day began at 11:30 a.m. and by 1 a.m. he is well into the brewing of Penn Pilsner, the brewery's most popular liquid refreshment.

"We brew through the night once or twice a week now that we're coming into the busy season," says Andrew Rich, brewery manager/head brewer who comes in around 4 a.m. "Nick will stay through the night a couple of times to keep it going."

Rich, 40, wears a T-shirt bearing a quote from Kaiser Wilhelm: "Give Me a Woman Who Truly Loves Beer and I Will Conquer the World."

Right now, with 4-month-old twin boys and a 2-year-old son, he's conquering fatherhood while also trying to keep up with the huge demand for output from his small brewery.

"It's really putting a strain on us to produce as much as everybody wants," he says.

Penn Brewery, which also has a restaurant featuring German food, produces 650 cases or 15,600 bottles of beer a day.

Beer drinking is easy.

Beer making? Not so much.

"Everybody thinks there's beer waterfalls ... everywhere," Rich says. "It's a good work but it's hot, dirty work."

It's a work that takes Rosich back and forth between the sunset-like glow of the brew room with it's copper-colored kettles, terra-cotta tile floor and red-painted beams to the fermentation cellar, which is actually a room with bright lights, metal tanks and octopus-like red tubing across the floor.

The air is pungent in the fermentation room and Rosich explains that it's probably the peracetic acid used to clean the tanks.

"It's pretty nasty stuff," he says. "It binds to all organic matter and helps remove it."

Later in the shift, when he cleans one of the tanks, the brewer dons rubber gloves and goggles to mix 4 ounces of peracetic acid to 31 gallons of water.

"I started making mead at 18," Rosich says, recalling his entre into beer making.

After constant reminders from his mother that making alcoholic beverages at 18 was illegal, he quit. Three years later, at the legal age of 21, he started making beer at home.

A couple of months later, he brought his parents some ale, his father's favorite drink.

His dad loved it.

I said, 'Oh, by the way Dad, I made it,' " Rosich explains.

Despite his interest in beer making, he entered Youngstown State University to study criminal justice. But he decided he preferred the rubber boots and harsh detergents he uses in the beer-making process to guns and bullet-proof vests.

So Rosich enrolled at the Siebel Institute of Technology in Chicago to take brewing courses such as yeast growth and fermentation, wort boiling and the always popular hops. Rich also studied there.

There's a lot of science involved in beer-making: organic chemistry, fermentation, aeration. It's enough to make your eyes glaze over when Rosich begins explaining the process.

Penn Brewery employs the German technique. In fact, when founder Tom Pastorius opened the Penn Brewery in 1986 on the site of the old Eberhardt & Ober Brewery on the North Side, he brought over everything from Germany, including the fermentation and aging tanks and the kegging and bottling equipment.

Even the controls are in German. The ingredients come from Germany, too. The brewery buys a year's supply of hop extract, which comes in cans, and hop pellets.

It's about 2:30 a.m. and once Rosich checks the level of the wort, the sugary liquid created by the "mashing" of malted barley that's boiling in the brew kettle, he traipses past the storage area stacked with mini-kegs to an outside shed to get a sample of the yeast. Rosich opens the spigot of a tank that stores the yeast and the thick yellowish goop plops into a big white plastic bucket.

It doesn't look like anything you want to put into something you're going to consume.

But as we said before, it's all about the yeast, which will make alcohol by fermentation in the wort.

Back inside the brewery office/mini-lab, Rosich puts a little yeast onto a slide to look at under a microscope to check the yeast viability. He wants more live yeast cells than dead ones because after all . . . well, you know.

The yeast live cell count is right where it needs to be at 95 percent. The yeast solid-to-liquid ratio is good, too, so Rosich does a little work on the computer until it's time to measure out the hop pellets and open a can of hop extract, which looks kind of like concentrated seaweed.

It's 2:53 a.m. and in about 30 minutes, Rosich will lower the extract into the boiling wort.

When Rich comes in, he gets an update from his overnight brewer and adds the first bowl of hop pellets to the mixture about 4:15 a.m. By the time the sun comes up, the yeast will be added, then the mixture will be cooled and oxygen added to make a better environment for -- the yeast.

By the time the process is completed, the Penn Pilsner brewed during Rosich's shift should be ready for shipment in early August.

But he's not waiting until then. Around 5:15 a.m. at the end of his nearly 18-hour day, he's sitting at the bar in the restaurant enjoying one of the perks of the job from a Pilsner glass.

"Lotta times," he says, "at the end of a long shift, it's nice."