Cyser is a type of mead where all (or some) of the water used to dilute the honey is replaced with apple cider. Over the years, I have made many batches of cyser and making it has become a Fall tradition for me. Here is a basic recipe for a 5-gallon batch of spiced cyser. Cheers.
Yeasts are small single-celled microorganisms classified as members of the fungus kingdom. More importantly, the species Saccharomyces cerevisiae loves to convert carbohydrates (sugars) into carbon dioxide and alcohols (ethanol mostly). There are also some other yeast species and bacteria that are utilized to make mead, wine, beer, etc., but Saccharomyces cerevisiae is king.