Sikhye (식혜) is a sweet, cold Korean rice drink with soft grains of rice floating in it, served after meals, at holidays such as Chuseok and Seollal, and sold in cans everywhere. It’s made by steeping cooked rice in water drained from barley malt powder (yeotgireum) and keeping it warm for several hours until the rice grains float and the liquid tastes sweet; it’s then sweetened to taste, boiled, chilled and garnished with pine nuts.
Is Sikhye Fermented?
The everyday kind, mostly not. The sweetness comes from enzymes, not microbes: when barley sprouts, it makes amylase enzymes, and in the warm malt water they break the rice starch down into sugars, mainly maltose – the same step that starts beer brewing, and similar to how koji enzymes sweeten Japanese amazake. The enzymes work best warm (roughly 55–65°C), and the finished drink is boiled, which stops them. It contains no live cultures and no alcohol.
If sweet rice liquid is instead left for yeasts to work on, you’re on the road to a rice wine such as makgeolli – but that’s made with a deliberate starter (nuruk), not by leaving sikhye out. Sikhye that turns sour or fizzy has spoiled.
Andong Sikhye: the Fermented One
The city of Andong makes a very different, genuinely fermented sikhye: glutinous rice, malt, radish, ginger and red pepper, giving a red, spicy, sour-sweet drink with crunchy radish. In a study that followed it during fermentation and storage at 4°C, its pH fell to a low of 3.9 after 20 days and its maltose rose from 6.35 to 9.85 g per 100 ml (Choi et al., 1991). It’s closer in spirit to a water kimchi than to the canned drink.
Keeping It Safe
Rice can carry spores of Bacillus cereus, a bacterium that causes food poisoning when cooked rice dishes sit warm. Its spores are heat-resistant: in a study of sikhye, they needed 2.8–4.9 minutes at 95°C for each 90% reduction (depending on the liquid and spore load), which is why a commercial study looked at extra heat treatments to control them (Kim et al., 2012). A 10-minute boil at home reduces them but doesn’t reliably eliminate them, so:
- keep the incubation warm (55–65°C) and no longer than needed – don’t leave the mixture lukewarm;
- after boiling, cool the sikhye quickly (a cold-water bath helps) and refrigerate it;
- drink it within a few days, and discard it if it turns sour, fizzy or smells off.
Sikhye and Health
Sikhye is a sweet drink: the malt converts rice starch into sugar, and most recipes add more sugar on top. It’s caffeine-free and refreshing, but treat it like other sugary drinks rather than as a health tonic – and since the boil stops the enzymes, it doesn’t help digest the meal it follows. For a Korean fermented food with live cultures, see kimchi.