National Brewery Centre

Time Travel in Denmark

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When Carlsberg invited a bunch of beer journalists from around the world to Copenhagen, it seemed like there was something important brewing.

Carlsberg RebrewVery often, this sort of no-expense-spared event involves some dry corporate announcement but refreshingly, on this occasion, the focus was on beer itself and, more particularly, on Carlsberg’s significant role in the development of modern beer.

The nineteenth-century founder of the brewery, JC Jacobsen, was an outward-looking man.

He never wanted the business to be bigger than he could control himself – it was his son, Carl, who expanded the empire – and he was always happy to share best practice with other brewers.

When the Carlsberg Laboratory was established in 1875, it was set up on the understanding that any scientific advances it made would not be hoarded or patented but distributed, free, to the wider world.

Over time, this would see important breakthroughs such as the creation of the pH scale and the development of enzymes useful in clothes laundering given away, although perhaps the most significant donation was a perfect brewing yeast to the global brewing industry.

It was at Carlsberg in 1883 that scientist Emil Christian Hansen, building on work begun by Louis Pasteur, worked out that off-flavours in beer were not simply caused by bacteria but also by the presence of more than one yeast strain fermenting the beer.

Pure Strain

By painstakingly isolating the less welcome yeasts, he discovered one pure strain that would guarantee clean flavours. This pure culture, given the name Saccharomyces carlsbergensis, went on to become the father of all lager yeasts used by breweries around the world.

Carlsberg RebrewOf course, the yeast that bears that name today will have mutated many, many times since its discovery, meaning that it doesn’t deliver quite the same results as it did back in 1883, but the discovery of three old bottles of beer from that very year, deep in the cellars of the brewery, has made it possible to appreciate what a beer from that time may actually have tasted like.

Because the bottles were filled in the days before pasteurisation, there was just a chance that some living yeast might have survived in the beer and so the Carlsberg Laboratory set out to try to retrieve it.

In move suggestive of a scene from Jurassic Park, the scientists brilliantly managed to give the yeast the kiss of life and then propagated enough of it to ferment a new batch of beer.

Any brewer will tell you that, when you’re trying to recreate an old beer, it’s no good just following an old recipe. Processes and ingredients have moved on so much that the original notes can be no more than a guideline. The old brewing books need to be interpreted for the modern world.

This meant Carlsberg couldn’t just use their regular barley malt for this special brew. They had to go looking for a variety of the cereal that might have been around at the time when the recipe was devised.

They found the answer at the Nordic Seed Bank and acquired ten grains of a barley that was in use during the 1880s. This they cultivated into sufficient quantity to fill a mash tun and, for authenticity, had it floor malted in the traditional way at a whisky distillery elsewhere in Denmark.

Some of this grain was then roasted at Carlsberg to produce Munich and caramel malts to match those indicated by the recipe for what was a Vienna-style lager.

The dusty old pages didn’t specify which hops were used in the 1883 brew, but brewers’ famous rule of thumb suggested they were probably German, and so Hallertauer Mittelfrüh were chosen – whole flower, of course, not pelletised.

The wells that once served the Carlsberg site are no longer accessible and so the character of the original brewing liquor needed to be reconstructed by adjusting the mineral content of the current supply. Everything was now ready for action.

Pilot Brewery

In the Carlsberg Laboratory, they have a cute little two-hl pilot brewery, which is used for trials and experiments, helping to develop soft drinks as well as new beers, some of which are then upscaled in the larger onsite Jacobsen brewhouse – Carlsberg’s ‘craft beer’ arm.

Carlsberg RebrewIt was in the pilot brewery that Rebrew, as it became known, came to life, the mash triple decocted as in the old days, with all the equipment’s computerised controls turned off to allow the brewers to manipulate the process by hand.

Fermentation took place in steel tanks that were deliberately opened up to mimic the open vessels of the nineteenth century. Two months of lagering then followed.

The final beer achieved an ABV of around 5.8%, from an original gravity in the region of 1.062, which reveals that the revitalised yeast, working with those old-style ingredients, was not particularly efficient when fermenting the brew, leaving plenty of residual sugars and body.

Back in the day, a beer like Rebrew would have been delivered to bars in wooden casks and so, for a final flourish, the beer was racked into an oak barrel. But it only remained there for a week, so that the woody notes didn’t become over-pronounced.

When the week was up, it was time for the great unveiling, in front of that assembled throng of beer journalists and dignitaries. Even the Crown Prince of Denmark turned up to show his support at a dinner later the same day.

With great ceremony, brewmaster Eric Lund washed the tap of the cask with alcohol, drew off and discarded a little of the contents and then proceeded to pour the samples.

The beer raced into the glass a hazy red-amber colour, foaming initially but settling down to a low carbonation.

Held to the nose, it offered notes of toasted grain, nuts, cereals and hints of grass. On the tongue, it felt soft and mellow, a bittersweet drink with a drying backnote.

Malt flavours were well to the fore, with roasted nuts and caramel just offset by a delicate hop character that emerged more prominently in the dry, bittersweet finish, sharing the limelight with chewy, toasted grain and more caramel.

As a beer for drinking today, it had potential, but would need some work. The carbonation would be the first thing to address if this was to go on commercial sale. A little more fizz would be needed to lift and separate the malt flavours, improving its complexity and quaffability.

Unique Impression

But all that is missing the point. Let’s remember that this was purely an exercise in recreating the past, an attempt to reconstruct what beer was like nearly 140 years ago and its merit lies in the fact that it offers an unique impression of what that first ever ‘clean’ lager might have tasted like.

Carlsberg RebrewJust put yourself in the shoes of the drinkers in 1883 for whom it must have been a revelation. For the first time, they would have been able to fully appreciate the true flavours of malts and hops without the intrusion of rogue yeasts that would have distorted the taste. There must have been quite a ‘wow’ factor.

For the brewers, there was also the realisation that beer, from then on, could always be consistent. There would be no more strange swings of flavour from brew to brew.

Carlsberg today makes great play of the company’s philanthropic history, and rightly so. It has been a benefactor to not just the brewing community but to the scientific world as a whole.

At a time when the business is potentially being squeezed by the rise of craft brewing from below and the planned merger of AB InBev and SABMiller from above, it makes sense for Carlsberg to stand its ground and re-emphasise its integrity.

Among the giant brewing companies, let’s remember, Carlsberg was early into the speciality beer fray, launching the Jacobsen range back in 2005. This implies that they have their ears to the ground and have responded in some way to what drinkers want.

At the same time, when big financial deals are going on all around them, they are keen to show that they are brewers with soul. ‘It’s not all about money’, you can almost hear them saying.

The Rebrew project fits perfectly into this scenario, re-establishing the company’s heritage and credentials at an important moment in the evolution of the global beer market.






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