If you’re working outdoors in the heat of the day, consider taking some switchel with you: roughly three cups of cider vinegar in ¾ of a gallon of water, plus some honey and some ginger. Cider vinegar supplies potassium and the ginger helps potassium absorption. Honey both revives your energy and reduces the tartness. Variations of this concoction have been used by farm workers since before the Civil War.