Ancient recipes were often fluid "grogs" that mixed whatever was forageable or traded. Make Mead Like a Viking · Fermentology
The stick’s porous surface would become caked with dormant yeast from previous successful batches. Make mead like a Viking : traditional technique...
Vikings didn't have a modern understanding of microbiology, but they mastered the results. A central part of their technique was the —a wooden stir stick (often birch or juniper) passed down through families. Ancient recipes were often fluid "grogs" that mixed