Is Soju Gluten Free? Find Out Here!

Is Soju Gluten Free?

Yes – celiacs, you’re in luck!   Korea’s favorite poison, soju is such a staple of Korean culture that it’s been dubbed “the drink of the average working Kim”. It is, however, distilled from rice grain – which can seem suspicious to gluten-intolerant stomachs.   Let’s break down the science of how a rice-grain product can, in fact, be gluten free.

Soju: Mongols’ Booze

Soju is a clear, colourless alcoholic beverage. Usually sold in green bottles, Soju brands sell at a wide range of alcoholic content. They run the gamut from drinkable, fruity 12.9% ABV, to a mind- and mouth-melting 53% ABV.   It was first distilled by the Yan Mongols during the Goryeo Dynasty in the 13th century. The mongols themselves picked up the process of fermenting grains from their conquests in Persia.   The fermentation process of soju traditionally uses rice grain. Steamed rice is placed in a sealed vat, then a few vital ingredients are added. Water, nuruk enzyme, and wine yeast get stirred into the mix, each with their own individual function.

The Miracle of Yeast.

The fermentation process, written in plain English, looks like a bit like a spell:

glucose →  ethanol + carbon dioxide

This process single-handedly supports the entire alcohol industry, and many believe that this equation is as old as human civilisation. 

As the lukewarm rice grains sit in their vat, the yeast starts busily consuming the grain mash’s glucose. This creates that all-important ethanol.

Nuruk enzyme is a fermentation starter that dates back to Edo times. This enzyme helps jump-start the fermentation process, shortening the fermentation time to a period of less than a week.

All alcohol yeasts have a maximum alcoholic percentage that they can function at. This usually tops out at 14% ABV, however. After roughly five days, the soju mash has reached roughly 10% ABV, and the fermentation process has largely ceased.

The vat of soju mash now resembles a tub of cloudy liquid; the spent rice grains sit at the bottom in clumps. This mixture is called chongju and most definitely contains gluten!

But most soju is over 15% ABV: how does this cloudy liquid become a clear bottle of potent soju?

First, let’s clarify why gluten is such a danger for some.

How Gluten Can be No Good.

Gluten is a wheat protein. When you consume a piece of bread, for example, this gluten is processed into amino acids and absorbed into the bloodstream around your small intestine.

However – when suffering with coeliac disease – the immune system views these gluten molecules as foreign particles and launches an immune response. White blood cells begin to attack not only those gluten molecules, but also the delicate tissues in the small intestine known as villi.

This causes a great amount of discomfort, along with symptoms including indigestion, vomiting, diarrhea and ataxia.

So it’s vital to avoid gluten. How, then, does a rice-grain beverage become gluten-free?

Distillation: the Secret to Soju

The distillation of alcohol is how soju becomes an artisanal liquor. The cloudy liquid is siphoned from the vats, filtered through cheese cloth, and poured into a still. In traditional soju making, this resembles a closed, bulbous copper pot, with funnels and tubes leading away from the top.   The distillation process takes advantage of different liquids’ boiling points.   The chongju, after being filtered, now contains only two major components: starchy rice water, and ethanol. Whereas the water will start to turn to steam at 200’F (100’C), the ethanol will become vapour at only 172’F (78’C).   As the ethanol boils up and out of the mash, it is funneled into a condensing coil. The sudden contact with cold temperatures forces the ethanol to return to a liquid state, which drips into its own container.   This process then leaves you with a clear, neutral-flavoured liquid with an incredibly high alcohol content. There is almost no gluten in this final product, as the starchy water has been left in the distillation still.   Finally, the high-ethanol liquid is cut with distilled water, reducing the ABV to (slightly!) more palatable levels.

Enjoying Soju

With no threat of celiac mishaps, soju can be enjoyed with other Korean staples like pork belly, or beef stew.   Some brands of soju add sugar to give their soju a sweeter flavor, as soju is traditionally taken neat as shots, or added to sweet cocktails. Whilst some compare the taste of soju with that of vodka, it’s largely accepted that soju has a less aggressive flavour than its distilled Western counterpart.