Dark, dusty cellars can hide treasures as renovation workers at Carlsberg’s head office in Copenhagen, Denmark discovered when they cleaned out some old cellars there some three years ago.

What they stumbled on were bottles of an old Carlsberg brew dating back to the 1880s, a time after Danish mycologist and fermentation physiologist Dr Emil Christian Hansen had developed a technique to isolate pure yeast for use in brewing.

When the Carlsberg Research Laboratory found out about the discovery, it set about trying to see if it could extract living yeast cells from the vintage beer.

“When laboratory head Birgitte Skadhauge told me what they had found, I immediately told her the foundation would authorise a grant for the research,” says Carlsberg Foundation chairman Flemming Besenbacher in a recent interview in Copenhagen.

After a year, scientists at the laboratory managed to extract pure living yeast cells from the bottles and project ReBrew was born.

The discovery came at the perfect time for Carlsberg, in the run up to the 140th anniversary of the Carlsberg Research Laboratory, and it decided to see if it could recreate that iconic first beer made with the original Saccharomyces carlbergensis yeast.

The project also served to highlight the lab’s four areas of research – Barley, Yeast, Ingredients and Brewing Technology.

A special dinner in honour of the ReBrew Project was held in the home of Carl Jacobsen, which is now an in-house museum for Carlsberg.

The home of Carl Jacobsen, which is now an in-house museum for Carlsberg.

To celebrate the recreation, Carlsberg invited a group of beer experts and media personnel to the company’s headquarters in Copenhagen to be present when the first, and possibly only barrel, of the special beer was tapped.

Ahead of the unveiling, the group was split into three for a tour of the Carlsberg Research Laboratory where we were taken through the steps necessary for the recreation of the classic brew.

In the barley section, Skadhauge explained that the records showed the barley was from the Gammel Dansk (Old Danish) variety and they managed to get 10 grains of the variety from a Norwegian seed bank before planting and propagating it, eventually ending up with 10 tonnes of the grain.

In an effort to stick to its roots, the barley was then sent to a whiskey distillery in Jutland, Denmark, to be malted with the traditional method of floor malting process still carried out there. At the heart of the beer, though, is the yeast and it is impossible to overlook the importance of Hansen’s work in developing a pure yeast strain.

After Carlsberg researchers managed obtain the pure strain from those old bottles, they were surprised to find that there was not much deviation from the current strain being used, showing that it was, indeed, stable.

Carlsberg head brewer Erik Lund explaining some of the new ingredients Carlsberg is experimenting with to come up with special brews in its research lab.

Carlsberg head brewer Erik Lund explaining some of the new ingredients Carlsberg is experimenting with to come up with special brews in its research lab.

Prior to Hansen’s work, beer was almost a hit-and-miss affair as wild yeast could lead to “beer sickness”. Thankfully, Hansen’s efforts took the guesswork out of the process and paved the way for standardised beer that could be enjoyed with no worries about taste or consistency. This strain of pure yeast would later travel the world, thanks to Carlsberg founder JC Jacobsen’s insistence that the results from the lab would not be kept a secret and he even sent the yeast to other brewers to use, including a certain Heineken from the Netherlands (according to a letter of thanks found in Carlberg’s vaults).

The final key to the puzzle that is beer is, of course, the water; and the original Carlsberg brew was made using water from a 20m-deep well dug in 1883 at the company’s premises in Valby, Denmark.

Sadly, the well has long since dried up but head brewer Eric Lund said the archives gave them all the information they needed to recreate this water.

“We had water analysis reports from the time and we replicated the mineral content the water used in the ReBrew project,” says Lund.

According to him, the only bit of guesswork that came with recreating the old recipe was in the hops used.

“We knew that the hops came from the Hallertau region, but not which variety. We finally decided to settle on the Mittelfruh,” he adds. Only 400 litres of the rebrewed beer had been made.

There's treasure in the cellars under Carlsberg, like these dusty vintage brews. The cellars were also where Carlsberg unearthed several bottles of its very first brew using the pure yeast strain from 1883.

There’s treasure in the cellars under Carlsberg, like these dusty vintage brews. The cellars were also where Carlsberg unearthed several bottles of its very first brew using the pure yeast strain from 1883.

Lund also explained that the mash had been very well detailed in the records so that was not a problem when it came to the brewing process.

After everything had been put together, the beer was put into wooden casks specially made by Lithuanian coopers and lagered for two months.

“All that remains to be seen is whether it will be perfect; whether it will turn out flat or foamy,” says Lund before inviting us all back to Jacobsen’s home for the big untapping.

The process was almost magical and it took some research work to get it done but all that remained was to see if those Jurassic Park-like techniques had been successful after all.

As the barrel was rolled out into the middle of the hall, there were looks of trepidation on the faces of all concerned, and Besenbacher and Carlsberg CEO Cees ‘t Hart looked on nervously as Lund got down to the task of pouring out the beer.

Carlsberg head brewer Erik Lund tapping the barrel and pouring out the rebrewed beer.

Carlsberg head brewer Erik Lund tapping the barrel and pouring out the rebrewed beer.

Beer historian Martyn Cornell holds up a glass of the rebrewed beer. Photo: Carlsberg

Beer historian Martyn Cornell holds up a glass of the rebrewed beer. Photo: Carlsberg

From the first pour, sighs of relief could be heard throughout the room as Lund pronounced, “It’s good!”

Besenbacher and ‘t Hart were the first to sample the beer and pronounced it fit to drink before glasses were filled for the 80 or so guests and Carslberg representatives in the room.

So how did it taste?

As beer historian Martyn Cornell put it, it was not a beer to knock anyone’s socks off, adding that this had never been what it had been all about.

It was a celebration of the efforts of a lab that, thanks to Dr Emil Christian Hansen, had taken the voodoo out of brewing. In effect, Hansen led to mass-market brewing and this brew was the one that started it all off.

This writer, for one, enjoyed my glass of the amber-coloured brew. It could have done with a bit more conditioning but flavourwise, the bitterness was well-balanced and it had a good finish that did not linger too long.

As some of in this group commented, it was something we would have enjoyed in the evening, and it did give us an insight into the tastes of the 1880s.

Of course, something as special as this deserves to be stored and Carlsberg turned to Holmegaard, the oldest glassworks in Denmark, which had been supplying beer bottles to Carlsberg since the 1850s.

At Holmegaard, Peer Nielsen worked with glassblower Anders Raad to recreate the iconic dark green bottle used for that very first brew.

One of these bottles was later autographed by Lund and presented to Crown Prince Frederick of Denmark at a special dinner in honour of the event.

The dinner turned out to be a stunning affair held in the former home of Jacobsen’s son, Carl Jacobsen, who did for art what his father had done for science. Carl established the New Carlsberg brewery, which was later merged with the original brewery under the auspices of the Carlsberg foundation.

He also amassed one of the largest private collections of art in the world and set up the New Carlsberg Foundation to look after this art. Today, the collection still stands and visitors can get a peek at some of the artworks in the Ny Carlsberg Glyptotek in central Copenhagen, opposite the offices of the Carlsberg Foundation.

Carl’s home is now an in-house museum with some stunning examples of his collection on display, and it was fitting that we enjoyed a spectacular dinner here to celebrate the success of the ReBrew project.

Dinner was an intimate affair with only about 120 people in attendance, with former Noma head chef Torsten Vildgaard serving up a seven-course menu paired, of course, with some of the Jacobsen Brewery’s best beers.

Vildgaard, who has already picked up a Michelin star at his own restaurant Studio, said he had been inspired by the tale of the yeast when he decided to come up with the menu and fermentation and pickling were featured heavily throughout the dishes.

He certainly rose to the occasion and served up some great dishes that did not disappoint. One highlight, for me at least, was the dessert of Sorrel with Sheep’s Yoghurt and Pine, which was paired with a special Jacobsen beer brewed using white wine yeast instead of the normal brewer’s yeast.

All in all, it was a celebration of passion befitting Carl Jacobsen’s personal motto Semper Ardens (always burning), which is still very much a key for Carlsberg of today as it was 140 years ago when the first pure strain of yeast was extracted in the rooms of the Carlsberg Research Laboratory.

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