The official blog of The Daily.
Download the app for the full interactive experience.
Increasing the alcohol content in beer is a delicate and complicated science. In fact, there’s a technical name for it: “Fractional freezing.”
Because alcohol and water freeze at different temperatures, you can take a low-alcohol beer, put it in the freezer, and wait. What freezes is lower in alcohol, what doesn’t is higher in alcohol. Remove the ice and what’s left will be substantially stronger — not pure alcohol, but more alcoholic than before. The process is called “fractional freezing.” The resulting beer — its origins are debatable and lost to history, but are believed to have emerged from Germany in the 1890s — is called “ice bock” or “eisbock.”