Not All Sake Is Gluten Free

Most types of saké exported to the US are safe for celiacs, but the main variety of sake made in Japan might not be gluten free. We’ll explore the reasons sake isn’t always gluten free below, and let you know which variety should be avoided.

Table of Contents

• How Sake Is Made
• Sake Koji Is Gluten Free
• Distilled Alcohol In Sake
• Barrel Ageing Considerations
• Why Futsushu Sake Might Not Be GF
• Premium Sake Is Always GF

How Sake Is Made

Sake is made from rice, so you can rest easy that the main ingredient is always naturally gluten free. After the rice is selected, most varieties of sake require the rice to be milled to refine the grain. After polishing, the rice is washed and soaked, then steamed. The steamed rice is spread out to cool to the correct temperature before koji, the fermentation starter, is added. The koji rice is allowed to sit wrapped in a cloth for a few days to start fermenting. After this point, the koji rice is mixed with another portion of steamed rice, some sake yeast, and water. This mixture, called shubo (酒母), is fermented. When the rice is fully fermented it’s called moromi (もろみ). Moromi is pressed to remove the liquid and dispose of the spent rice grains. During pressing, brewers alcohol may be added to extract additional flavor compounds and increase stability. Further filtration is completed, then the sake is heated to stop the fermentation process. Namazake skips this process and is served raw, which means it has a much shorter shelf life than other types of sake.

Sake brewing is very labor-intensive but relatively straightforward. Now that we have a general understanding of how it’s brewed, we can address the parts of the process that might affect the sake’s gluten levels.

Sake Koji Is Gluten Free

There’s a misconception that some types of sake use barley-based koji as a fermentation starter. This is incorrect. It’s legally required that all regulated types of sake use a rice-based koji to start fermentation, so the inoculant is safely gluten free. One exception here is futshu-shu, which can’t be verified, because it isn’t closely regulated.

Distilled Alcohol In Sake

Some people are worried about the addition of distilled alcohol to certain types of sake. In fact, all types of sake besides the junmai-designated varietes have a small amount of brewers alcohol (jōzō) added during pressing. This is to bring out desired flavors and increase shelf stability. As noted in our distilled alcohol article, spirits are generally considered safe for people with Celiac disease, even if they’re made with wheat, barley, or rye. Either way, most distilled alcohol used in sake making is sourced from sugarcane. There’s no need to avoid sakes that have added brewers alcohol.

Barrel Ageing Considerations

Most sake is aged in steel tanks or bottles, but it can be sealed in wooden barrels for ceremonial purposes. Japanese barrels are sealed with bamboo nails. On the rare chance you purchase a wine barrel aged sake (sometimes used for flavoring purposes), it would be considered gluten free, even though some wine barrels are sealed with a wheat flour paste. Competitive ELISA testing has been done on wine aged in barrels sealed with wheat paste and these tests have shown the lowest result possible for the testing equipment at <10ppm. We recommend checking out this GF Watchdog article for more details.

Why Futsushu Sake Might Not Be GF

Futsushu (普通酒) makes up over 75% of the sake brewed in Japan. Futsushu means ‘ordinary sake’ and is a style brewed with the ingredients that are available and affordable for the brewer. This most often means they use rice that’s been polished less than the required amount to fit within the special-designation sake (特定名称酒) classifications. It’s like the ‘table wine’ of Japan.

Because it’s less regulated, it could possibly contain gluten in flavorings or additives, although it’s unclear how often that’s the case. In my research, some articles stated that Futsushu could contain MSG, which would make it not gluten free, but that’s outdated information because MSG is safe for Celiacs. Either way, it’s probably best to skip Futsushu-style sakes because their ingredients can’t be confirmed. It’s worth noting that Futsushu isn’t exported to the US very often, so you’re unlikely to even have access to a non-gluten free sake in the States.

Premium Sake Is Always GF

When in doubt, ask about the sake type to make sure it’s safe for you. These are the different types of premium sake that are always gluten free:

• Honjozo
• Ginjo
• Junmai
• Tokubetsu junmai
• Tokubetsu Honjozo
• Daiginjo
• Junmai Daiginjo
• Junmai Ginjo