The organ is 15 meters by 15 meters, weighs 25 tons and is a special project. "Often, instruments are not played that often in concert halls; this is different," Klais says. There are organ solo subscriptions, tours where visitors can touch the pipes, and other concerts.

The instrument's location is also unusual. It is not enthroned above everything - as in churches - but blends in with the white facade of the large hall. So it's no surprise that cleaning is also done differently than usual. Klais and his team removed several thousand pipes instead of twelve just four years after the opening in order to clean them. The elaborate work began on January 4 and is scheduled to be completed by the end of February.

In 2016, the Bonn team had spent six months installing the instrument in Hamburg. "During the completion of the hall, many trades had access at the same time. There was a high dust level," says Klais, who has managed the fourth-generation family business since 1995. Therefore, even before the opening, it was clear that the pipes should be cleaned earlier.

The action was actually planned for the summer of 2021, but now, because of Corona, the Elbphilharmonie hopes that musical life will start again precisely then. "That's why the management decided in November: We're doing this now," says Klais. It is nice and unusual to work so quickly again with the finished instrument, says the organ builder.

In January and February, the specialists had free rein to dust off the 4765 pipes. How they do it depends on size and closure. "We work with suction cups and brushes," says Klais. For large pipes, he says, they use real vacuum cleaners. The longest organ pipe in the Elbphilharmonie measures more than eleven meters, while the shortest is a few millimeters long. "We can get into the very large pipes that way, we don't have to lift them out," says Klais. "Thank God."

Now in February, an exciting phase began for Klais: "After cleaning, the pipes will be re-intoned and tuned." Building the instrument, he says, is both art and engineering, but the most important thing in the end is the sound. Intonator Bernd Reinartz gives each individual pipe the right tone. To do this, he changes them only minimally. With a small spatula - similar in size to a brush for the space between teeth - he gently widens them, for example. "In contrast, dental mechanics is rough work," says Klais.

The organ now has four years of concert experience, Klais says. During that time, the organ builders from Bonn visited their work of art regularly to get to know it in action. Hamburg is not that far away, he says. "One of our organs is in Kaohsiung in southern Taiwan. We can't get there that quickly," says Klais.

From different seats in the hall of the Elbphilharmonie, the organ builders listened to the concerts and sometimes even discovered small spots that they now want to touch up. "These are fine nuances where I think: "At this point, at this small detail, I would like to see a careful correction," says Klais. Laypeople probably wouldn't even hear the difference.

For all the work, the organ builder coordinates with organist Iveta Apkalna and the organ expert from the city of Hamburg. On February 14, everyone met again for the final inspection. All work should be completed by the end of the month.

Klais is extremely pleased with the organ in the Elbphilharmonie: "I am very happy. It's a great instrument in a fantastic space." He is pleased that the organ's location is open to the public. „It's an attractive building that invites people who don’t usually go to classical concerts," he says, adding that he would like to see the same courage in his own city.

Klais` company, with 65 employees, builds three to four organs a year. He is currently restoring an 18th-century instrument in Wrocław (Breslau), Poland. Another project in Cairo is currently on hold because of Corona. Has the business always been this international? "My grandfather built the organ in the World Peace Church in Hiroshima," Klais says.

But the best example, he says, was organ builder Johann Heinrich Mundt of Cologne, who built the organ in the Teynkirche in Prague in 1671. Klais was allowed to restore it and was thrilled: "The organ can play music that had not even been composed when it was built. That is visionary."

(Original text: Christine Ludewig/ Translation: Mareike Graepel)