Lager’s mystery ingredient found

Missing ancestor of yeast used in cold-brewed beer is identified

Lager beers got their start in Bavaria, but it was a little South American spice that really kicked things off.

Galls — growths resulting from a fungal infection — grow on southern beech trees in Northern Patagonia. Scientists recently found a wild yeast that gave rise to a hybrid yeast used to brew lagers in such galls on trees growing in and near two national parks in Argentina.