I found online an ancient recipe for mead, given by the Spanish-Roman naturalist Columella in "De re rustica":
Take rainwater kept for several years, and mix a sextarius (around 1/2 litre) of this water with a [Roman] pound (about a 1/4 kg or half pound) of honey. For a weaker mead, mix a sextarius of water with nine ounces of honey. The whole is exposed to the sun for 40 days, and then left on a shelf near the fire. If you have no rain water, then boil spring water.
I've read that mineral water of low fixed residue is suitable for this. My questions are:
What are some tips (like the container, how to close the container)? How does the whole process work? How about the sun exposure part in winter?