Green Plum Syrup

The maesil tree is better known in East Asia for its blossoms than its fruit. It flowers in early spring before the leaves appear, and the Encyclopedia of Korean Culture describes how Joseon scholars prized it as an emblem of integrity for blooming through the cold. The fruit looks like a small green apricot and is intensely sour; it turns yellow around July. In traditional medicine, unripe plums were salted and sun-dried (baengmae) or smoked over burning straw (omae), and the 17th-century cookbook Gyugon siuibang describes a powdered plum vinegar made from omae.

Maesil-cheong is a home preserve in the same cheong family as citron and omija syrups. Washed, stemmed plums are packed into a sterilized jar in layers with sugar at roughly 1:1 by weight, left at room temperature for three to four months until the sugar has drawn out the juice, then strained; the syrup is aged further before use. Green plums come to market in early summer, which is when most home batches are made.

In the kitchen, a spoonful of the syrup brings sweetness and gentle acidity to muchim dressings, vegetable pickles and meat marinades, and it is diluted with cold water as a summer drink. The Korean Food Composition Table lists several plum cultivars grown in Korea, including Namgo and Cheonmae.

• Mostly sugar: Per 100 g, plum syrup in the Korean Food Composition Table contains about 44 g of sugars and little else of nutritional note. Treat it as a sweetener, not a health tonic.
• Traditional use: Plum preparations have long been used in Korean traditional medicine; the Encyclopedia of Korean Culture lists traditional uses for diarrhea and coughs. These uses are traditional rather than clinically established.
• Amygdalin in seeds and unripe fruit: Maesil seeds contain amygdalin, a cyanogenic compound that can release hydrogen cyanide in the body; Korea's Ministry of Food and Drug Safety (MFDS) notes that large amounts can cause headache, dizziness and breathing difficulty.
• Making it safer: MFDS guidance says removing the seeds cuts cyanide compounds by about 95 percent, and using ripe yellow plums instead of green ones cuts them by about 70 percent; it also advises straining out the fruit after three to four months and aging the syrup at least six more months. A 2024 study found amygdalin in syrups fell sharply over the first nine months and was below 5 mg/L by twelve months, regardless of fruit ripeness.
• Never eat the pits: Do not crack or eat plum seeds, and do not eat raw, unripe plums.