The Tate has defended its decision to advertise for a "head of coffee", on wages of almost £40,000 a year.
Union leaders had said the post highlights "the pay discrepancy" between museum professionals and others within the arts sector.
The average annual salary for professional art curators in London is believed to be around £37,300.
The Tate told the BBC: "It's unfair to compare a head of department with a curatorial role of a different level".
"All Tate's departments have a variety of roles with different responsibilities and salaries," a spokesman said, "including curatorial, and a more accurate comparison would be a curatorial team leader."
The museum said curatorial team leaders can be paid around £50,000, while assistants may start on £17,524, as guidelines show.
"We value all our staff and strive to pay them appropriately for their work at Tate," the statement concluded.
The advert for the role, based at Tate Britain, describes it as "a unique role with that encompasses all aspects of coffee within the four Tate Galleries".
"The job entails sourcing, blending and roasting coffee for use in all Tate Eats' sites and managing the Hot Beverage Team that is responsible for all aspects of tea and coffee delivery."
The required skills listed include extensive experience of cupping (the practice of evaluating the aroma and flavour profile of coffee) and espresso quality assessment.
'This cannot continue'
The Tate houses the UK's national collection of British and international modern and contemporary art, including the recent William Blake exhibition.
Alan Leighton, national secretary of the trade union Prospect, said the new job underlines how poorly its specialists are paid by comparison.
"The pay discrepancy highlighted is a stark reminder, not that the head of coffee is paid too much but that highly qualified museum professionals are paid far too little," he said.
"Across the sector it is clear that roles which exist in other sectors are paid well, while heritage-specific roles are paid appallingly."
In October, workers at a some of England's most popular museums went on strike in a dispute over pay.
"This cannot continue. Without these qualified specialist workers there would be no galleries and no museums. It's time that was recognised and those roles rewarded accordingly," Leighton added.
According to the latest stats from the British Coffee Association, the British coffee industry contributed £17.7bn to the UK economy in 2017.