A Brief History of Glögg, or Mulled Wine
Glögg, mulled wine, wassail and gluhwein are a few of the many names for warm spiced red wine, found in many cultures around the world and thought to have originated in 1st century Rome. The Romans travelled all over Europe, conquering much of it and trading with the rest. The legions brought wine culture with them, up the Rhine and Danube rivers and to the Scottish border, bringing their recipes as well. The drink could be served hot or cold and be alcoholic or non-alcoholic. Popular mainly in the northern parts of Europe, it was usually consumed during the darkest, coldest times of the year. Many different spices were used in different regions, as well as the addition of hard liquor to taste, for flavor and effect. It is worth noting that many glögg fiends found out the hard way that heating the glögg to more than 155' will burn off the alcohol and lessen the desired effect.
Don't lessen the desired effect. Don't heat it to more than 155' F, or 70' C.
How does it work? The warm liquid raises the temperature of the mouth and stomach slightly, and because alcohol is a vasodilator, it forces blood to the skin, making us feel warm and blushing on the outside.