Rượu cần – “straw wine” – is the jar rice wine of Vietnam’s highland peoples, especially in the Central Highlands. Cooked glutinous rice (sometimes mixed with other grains or cassava) is mixed with a dried starter, packed into an earthenware jar and sealed to ferment. At a gathering the jar is opened, water is poured in, and guests drink together through long bamboo straws, topping up the water as the level drops – so the wine gets lighter as the evening goes on.
The Starter: Men
Vietnamese rice wines start from men, small dried cakes or balls of rice flour carrying moulds and yeasts (often with herbs). In a study of Vietnamese rice wine starters, the best starch-degrading moulds were Amylomyces rouxii, Rhizopus oligosporus and R. oryzae – they turn the rice starch into sugar, and A. rouxii produced up to 25% glucose in the moulded rice. The yeasts that make the alcohol were Saccharomyces cerevisiae, which turned a 20% glucose solution into 8.8% (w/v) ethanol and tolerated about 9–10%. The best conditions were about 2 days at 34°C for the moulds to sweeten the rice, then about 4 days at 28°C for the yeasts (Dung et al., 2006). It’s the same two-step idea as Philippine tapuy and Korean makgeolli.
How Strong Is It?
The fermented rice mash itself can be as strong as a wine, but because water is added to the jar before and during drinking, what goes up the straws is weaker and gets steadily more dilute. There’s no single figure: it depends on the starter, the time and how much water goes in. A study of Vietnamese homemade spirits – distilled, unlike rượu cần – found methanol and other contaminants at levels that weren’t a public-health threat; the authors’ concern was the ethanol itself (Lachenmeier et al., 2009). Rượu cần is an alcoholic drink, not for children, during pregnancy or for anyone avoiding alcohol.
Making a Small Batch
You’ll need glutinous (sticky) rice and a men or other Asian rice-wine starter ball from a Vietnamese or Asian grocer (recipe card below). A wide glass jar works in place of a clay one; drink it with straws and water added, as tradition has it, or strain it. For the sweet, non-alcoholic first stage of a rice ferment, see Japanese amazake. Assam’s judima is another rice wine made with a starter cake.