Wolff ’s sweetening the beat

In an interview on Late Night with Seth Meyers, the CNN journalist, Jake Tapper, said the following about the author of Fire and Fury

Jake Tapper: Oh, yeah! I mean, I, I think Michael Wolff very clearly–and I think he's been pretty open about it. Umm... Early on, he wrote a vaguely flattering piece about President Trump […] it had a nice picture on the cover of er.. The Hollywood Reporter […] And then he did an early interview with Steve Bannon that was, umm, oh, offensively, er... just handing him the microphone an-and talking […] But it was all, what's called in my business, beat sweetening. He was sweetening the beat. He was gaining their trust and they fell for it.

I might have said Michael Wolff was softening the President up and the White House administration. Would that be correct or is sweetening the beat more negative, more backhanded?

Slate Magazine, in April 2009, defined it as

A beat-sweetener is a gratuitously flattering profile that a reporter writes about a government official in the hope that it will encourage (or, at the very least, not impede) that reporter's access to the official in question. … [It is] a meal prepared for someone other than yourself, and there's no reason you should waste precious time ingesting it.

• Is it jargon, only used by the press or do Americans use this expression in the workplace, at home, and at school? Is it relatively well known?
• What expression would the British press use?
• And what is this “beat” that is sweetened? The only thing that comes to my mind is the beetroot vegetable.

Journalists that emphasise positive aspects of the personality and behaviour of celebrities and politicians are often referred to as “beat sweeteners”; profiles of public figures which are flattering and non-critical. Beat in this phrase refers to the area of interest of a particular reporter. A journalist’s beat is the individuals or issues that they regularly cover in their reporting.

This “practice” is most often found in politics, especially in relation to the White House context:

A beat sweetener, as press-watchers know, is an over-the-top slab of journalistic flattery of a potential source calculated to earn a reporter access or continued access. They’re most frequently composed on the White House beat when a new administration arrives in Washington and every Executive Office job turns over, but they can appear any time a reporter is prepared to demean himself by toadying up to a source in exchange for material.

From Beat sweetener: The Benjamin J. Rhodes edition

Beat reporting

Beat reporting, also known as specialized reporting, is a genre of journalism that can be described as the craft of in-depth reporting on a particular issue, sector, organization or institution over time.

Etymology:

The term comes from the noun beat in the sense of an assigned regular route or habitual path, as for a policeman. By analogy, the beat of a reporter is the topic they have been assigned for reporting. Similarly, a beat reporter will follow the same routes or habitual paths in collecting new information on a specified topic.

From Wikipedia

The expression appears to be from 1988, and, as noted, is mainly found in political US White House contexts:

In a 1988 column for Newsweek, journalist Jonathan Alter used the term “beat sweetener” to describe how access-obsessed Washington journalists curried favor with the powerful politicians they covered.

“To keep access open, reporters need to coddle their sources,” Alter wrote. “In recent years, this cozy system of mutually assured seduction has grown corruptive…. Especially useful sources…are rewarded with occasional ‘beat sweeteners.’ The New York Times…has made a minor specialty of such puffy stories…. Some beat sweeteners are written partly out of hope for future morsels from an important source.”

Two decades later, the beat sweetener remains in fashion among the Washington punditocracy. In 2009, the Washington Post’s Anne Kornblut wrote a fawning profile of then–White House deputy chief of staff Jim Messina, whom Ken Silverstein of Harper’s deemed “the most egregious beat sweetener of the Obama years.”

From www.thenation.com

American policemen regularly walk a beat, that is, a regular route, paying special attention to areas more liable to crime. Adopting this term, newspaper reporters may be assigned a beat as well, such as local crime or politics, or even the White House.

A beat-sweetener, then, is a flattering profile (aka "puff piece") designed to curry favor with a regular news source on the assigned beat. It is jargon not in general use and appears primarily limited to Congress and the White House, thus Tapper's need to explain the term to his audience.