Hofstettner Granitbock Ice: The History of Eisbock, the Original 'Ice Beer'


Brauerei Hofstetten Krammer in Austria produces beer that is true to the guidelines of historic style, but the brewing process of their Granitbock Ice won't strike the average enthusiast as very traditional. With flavors of dark fruit brandy and a well-hidden alcohol content of 11.5%, you might also be surprised to learn that the extra step in the brewing process required to achieve these qualities is the same treatment used to create Bud Ice. To drink any beer in 2013 is to experience the culmination of hundreds of years of development, experimentation, and even a few happy accidents. For no style is this more true than for the German Eisbock. Once a rare find in the US, the last few years have seen more transatlantic shipping of bottles, and even occasional kegs.

To fully understand and appreciate Granitbock Ice, it is best to understand the style variations used to make it. Bocks are a strong, caramel-colored, malty lager with a thin, persistent head, and the Bavarian brew of choice for special occasions. Low on hops, the style is characterized by its malty flavors.

Hoffstetten brews a bock called Granitbock, so named for two reasons: First, the brewery acquires all of their raw materials locally, including their water, which uniquely flows through nearby granite aquifiers. Secondly, the Bock is brewed in the ancient style of a Steinbier, or 'Stone Beer.'

Steinbiers are brewed by boiling the wort with stones heated to around 800°f.  This style of applying heat to beer was born out of necessity, an effective way to heat beer in wooden tanks without torching them. This method was commonplace before the industrial revolution when metal became more affordable, making it easier to apply heat.

The reason some brewers continue using stones as a source of heat is at they act as a caramelizing agent. Rocks become candied, coated in a toffee-like sugar that doesn't ferment with the rest of the sugars, serving to both add to the flavor and color of the final product. What results is a grand take on a Bock, a practical 'Super-Bock.'

Hofstetten heats granite stones for their Granitbock wort, then doubles down by brewing it all in open-air granite troughs. And then it gets really interesting, because this is all just the starting point for their Granitbock Ice

Eisbocks are but one style of Eisbiers. Eisbiers are made with a peculiar brewing practice, and although its a relatively modern method, its precise beginnings are unknown. But no beer style history would be complete without a legend.

Rocks being heated for Steinbier
Rocks being heated for Steinbier

They say that a German brewery worker in 1890 was ordered one winter evening to bring a batch of newly brewed Bock inside at the end of a long day. Tired and alone, he decided that leaving the beer outside for the night would do no harm. Returning to work the next day, the head brewer discovered that, after a particularly frigid night, the beer had frozen solid. Well, almost...

The outside of the tanks were indeed frozen - crystallized and white. The inside, however, was still liquid. Thick and dark brown, it certainly wasn't the beer the team had intended to produce. Or a beer at all, so it seemed.

The legend continues: the story going that the brewer, furious with the spoiled remains, ordered the offending brewery employee to drink the strange brown syrup. The punishment wound up to be an enjoyable endeavor, and a style was born. Whatever kernel of truth may exist in this story, it does well to illustrate the process of fractional freezing, which is, in essence, a form of distillation.

Alcohol freezes at a lower temperature than water. So that night, as the outsides of the beer tank became cold, what crystallized with ice was only water. All the alcohol and flavor remained liquid. The freezing process also dulls the bittering agents in hops, as well as removes the tannic qualities of the hops and grains. Eisbier is still brewed this way today, an inexpensive way to increase alcohol and achieve a smooth creaminess.

North Americans might recognize the style more as 'ice beer.' Labbatt was the first to lay claim to that particular term with what would eventually be called Labbatt Ice, though Molson was the first to introduce it to the public with what is now known as Molson Ice. The early and mid 1990's then saw a spate of ice beers in America, including Busch Ice, Natural Ice, and Bud Ice, now one of the best-selling beers in the country. These variations on adjunct lagers reflect the Eisbier tradition with a higher alcohol content, though some of these are believed to be later watered down to bring batches down to a more reasonable level.

Granitbock Ice, photo by Matt Archambault
Granitbock Ice, photo by Matt Archambault

The reason big brewers are attracted to this involved extra step of the brewing process is that it also accelerates the lagering process, meaning breweries can get beer out the door faster and move on to the next batch. That changes the connotation of commercials that boast 'cold-filtered' beer.' Never has a shortcut sounded so desirable!

Back to Hofstettner Granitbock Ice. After the granite boils, the beer is cold-lagered for 6 months, then partially frozen. Brewers then chip away the ice to extract the Eisbock. The beer is oily, thick and dark brown. The off-color head vanishes instantly, but the beer leaves a thin tracing on the glass if supped fast enough. The flavor and aroma is strong, with notes of raisins, toffee, and smoke. The alcohol is well-hidden thanks to the strong flavors. There are no hop notes to speak of on the tongue, but one can catches whiffs of something herbal in the nose. Some people report a sourness. This could be a result of shipping damage, as it's not common for the style, or it may just need to be aged a bit.

German Eisbiers represent an interesting and important segment of modern beer culture. It is worthy of exploration both for lovers of imperials and barley wines, as well as beer explorers looking for something new and exciting. In the case of a granite Eisbock, new and exciting happens to cross paths with tradition.