Around 10 a.m. each day in December, Emma Lord goes into her New York City kitchen and, brimming with anticipation, plucks a one-ounce jam jar with a gingham-print lid from a tiny cardboard window.
Will today’s flavor be strawberry-rhubarb?
Or dragonfruit?
Could it be honey?
“The honey day is always an extremely controversial day for me,” said Ms. Lord, who along with tens of thousands of other Yuletide preserves enthusiasts counts down the days to Christmas each year with food-maker Bonne Maman’s Advent calendar.