Early Tuesday evening, Art and Peggy Joens will open up their two-storey farmhouse located off a gravel road in rural Manilla, Iowa, and, as they've done for the past 15 years, welcome a handful of neighbours to their makeshift Republican caucus.

"We don't know how many folks will show up, especially if it's a snowstorm," Art Joens said. "Sometimes it’s just my wife and I. We just sit there and look at each other for a while. And if my wife is mad at me, then there's almost complete silence," he said laughing.

"But half a dozen is a big crowd for us."

The Joens Residence, as it is listed on the 2012 Iowa Caucus website, is apparently one of only two private homes among the 1,774 precinct meetings to be held across the state Tuesday, as the Republicans kick off the process to elect a presidential nominee.

With more space needed to accommodate voters, private residence caucuses have faded away. Most of the events are now held at larger venues — churches, school gymnasiums, libraries and community centres.

As many as 20 people will show up at the firehall in Dawson, Iowa, to take part in the state-wide caucus meetings Tuesday. (Mark Gollom/CBC)

Some of the caucuses will also be held in firehalls, including in the small town of Dawson. As many as 20 people will gather there in a small room located just behind the garage, where fire gear hangs and three emergency vehicles are parked, waiting to be called into action by the town's volunteer fire department.

"That’s where we normally vote for elections," said Jeff Rosener, caucus chair for the district. "That's where I thought we might get a little bigger turnout."

Joens will hold his vote in his living room, serving up coffee and his wife's cookies to the gathered Republicans.

"It's really an informal type thing. No formal speeches. People just bring their knowledge and preferences and you just sit there and talk for a while."

It's just a convenient thing to do. We know most of our neighbours. It's just a convenient way to complete this process."

Ballots will be cast, hands raised

The rules of that process can vary slightly from caucus to caucus, but they're basically all the same. Around 7 p.m. each precinct meeting will take a presidential poll, which, in most places, is expected to last about an hour.

Before the vote is taken, the candidate, or more likely a representative of the candidate, will be given time to speak to garner support, usually between one and five minutes.

Then the votes are counted. In some precincts, participants will write the name of their preferred candidate on a ballot and place it into a box. In some smaller gatherings, a show of hands will select the winner. Those results are then sent off to the party to be tallied.

“When you have this small a number … everybody knows each other. We can count the ballots just as a group, openly,” said Richard Kercove, who is hosting what is thought to be the only other private residence caucus in Sigourney.

He and his wife have been hosting caucuses for nearly 50 years, the first when Barry Goldwater made a bid for the Republican nomination before his unsuccessful presidential run in 1964.

'A lot to organize'

After months of preparation, Polk County Republican Party chair Kevin McLaughlin said his organization is ready for the big day.

"This is a lot to organize. Polk County is the largest by population, so we have the largest number of precincts — we have 19 per cent — [and] almost 20 per cent of all registered Republicans in the state. That’s why so many campaigns are slugging it out here."

By far the biggest event will take place in Cedar Falls. Up to 6,000 people are expected to flock to the UNI-Dome where 63 separate caucuses will be held under one roof.

Some of the presidential candidates have signalled they may attend to try to drum up some last-minute support.

Mac McDonald, Republican chair of Black Hawk County, the fourth-largest county in Iowa, said the venue was changed after problems surfaced in 2008.

Organizers expected 1,000 to 1,500 people to attend that year, but double that amount came, McDonald said. Cars ended up everywhere, including on snowbanks, and they estimated about 2,000 didn't show up because they couldn't find a place to park, he said.

Speeches also went on too long and they had no way of cutting speakers off, he said.

"We were voting when Des Moines was announcing their results. It was not a pleasant experience."

Victory in Iowa can be a boost

This time, there’s plenty of space and parking for the caucus-goers, and the hordes of media expected to attend. An ambulance will also be on standby because in 2008 a woman’s water broke and they were unable to get her car out of the lot.

Organizers will also tightly control the length of speeches.

The size of the event has also attracted the attention of security officials, who will be checking for explosives before the event.

"We've had everybody from Homeland Security to campus police through. They’re worried about the [Occupy protesters] making a scene,” McDonald said.

Ironically, with all the focus on the caucus process, the results are actually not binding on the 28 delegates who will also be chosen that evening to attend the Republican National convention in August. There, they can actually vote for whomever they like.

Still, at the end of the evening, the winner of the Iowa caucus will be declared. And as Iowa is the first in the primary process, a victory can be a big boost to a campaign, just as a weak finish can deal a deadly blow.