This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
醦 combines 酉 (wine vessel) with 參, which likely contributes the sound. The exact historical meaning is uncertain, but it may relate to wine or fermentation.
The left side 酉 suggests a wine jar, and the right side 參 looks like a complex mixture. Picture a mysterious brew fermenting inside the jar, but its exact purpose is unclear.
For サン, imagine the sun (サン) shining on a wine jar, warming the brew inside: sun -> サン.