THE Coen Brothers have been making films together for 25 years and they are growing ever more productive.

After the four-time Oscar-winning No Country For Old Men in 2007 and Burn After Reading last year, Joel and Ethan have drawn on their Hebrew school background for a relatively low-budget movie centred on an academic family in the largely Jewish suburb of St Louis Park, Minnesota.

In a rare interview in London, the media-shy brothers discuss A Serious Man, a seriously dark comedy that questions faith, fate and mortality. CHARLES HUTCHINSON lends an ear.

How autobiographical is A Serious Man, Ethan?

“It’s not really autobiographical because the story is made up, but it’s certainly a movie that takes place in the community that we grew up in. It’s consciously been built up to recreate the era, so there are a lot of similarities to our background. We went to Hebrew school; our father was an academic – he was a professor at a mid-Western university; we grew up in a house like that and a neighbourhood like that; all those things I guess you could say are personal, but the story is all fiction.”

How does A Serious Man compare with your previous films, Ethan?

“I don’t know. We don’t really compare one movie to the other. We don’t think about it much, and whether it’s maturing or not. Some of them are more genre pieces than others, but this one isn’t. It’s the only one that doesn’t sit comfortably in a genre. For us, it’s a pretty unexamined question. We don’t really think about where we’re going, and what one is like to the other, whether we’re progressing or regressing.”

Has your working process changed over the past 25 years since your debut with Blood Simple?

Joel: “I think in a way it’s become a bit more professionalised than when we were in our 20s and sharing an apartment. Now we have kids and families. We go into an office every day and write.”

Ethan: “It feels like we’re fairly lazy relative to other people, yet we get a fair amount done. That just reflects poorly on other people. We get very little accomplished and yet we’re outpacing many of our peers so we can just sit back. When we were younger, we used to spend more time on the production. Longer days and six-day weeks, in terms of shooting.”

Joel rejoins: “We would work round the clock all around the year. But as we get older, we want to go home and spend time with our kids.”

Why did you choose unknown actor Michael Stuhlbarg to play the lead role of professor Larry Gopnik, Ethan?

“Mainly because of how we wanted the movie to feel. It’s a slice of life at that time. We wanted to immerse the audience in that setting. Putting a movie-star face in that setting would not help – it would diminish the whole feeling of it. Here we are in everyday reality, in a Jewish community in 1967; one doesn’t expect George Clooney to show up.”

Why did you decide to make Larry a physicist, Joel?

“We thought it was more interesting to make him a scientist with that way of looking at the world. In the face of the things that were happening to him, to a certain extent, he’s looking to spiritual leaders for answers. It was interesting to us that the more spiritual, mystical parts of the Judaic tradition were seen through the world of numbers.”

What comes next for the Coen Brothers, Joel?

“We’re doing an adaptation of a Charles Portis novel called True Grit, which was made into a movie in the late 1960s with the late John Wayne. It’s a Western and it’s going to star Jeff Bridges, Matt Damon and Josh Brolin. I don’t know if we’ve always wanted to make a Western. This was just a novel we both really liked, and the opportunity was there to do it.”

Are Westerns relevant to film audiences today, Joel?

“Sure, why not? So are vampire movies and outer space movies. I just don’t think we can make an outer space movie.”

• A Serious Man (15) is showing at City Screen, York.

Did you know?

Joel Coen turns 55 on Sunday.