There’s a sake for every occasion – and if you’re feeling festive, what could be better than a glass of sparkling sake?

Yes, sake can be made in a sparkling style, too, and it’s increasingly popular.

In everyday Japanese, sparkling sake is called just that – [スパークリング酒] or more precise “sparkling nihonshu” [スパークリング日本酒]. More technical terms are happouseishu [発泡性酒]or happoushu (happousei means effervescence, fizziness. Confusingly, cheap low-malt “beer” is also called happoushu). Another term is awa-sake [泡酒] (awa means foam). Both awasake and happouseishu can be used to refer to the whole category of fizzy alcoholic beverages, including sparkling wines.

Ichinokura in Miyagi Prefecture was the first brewery to produce a sparkling sake in 1998. Their “Suzune” [すず音] is a slightly turbid, light and off-dry sake. Radically different from the stereotypical sake of the 1990s, it was marketed to appeal to a new generation of independent urban women and is still one of the most popular sparkling sakes in Japan.

The story behind the first sparkling sake “Suzune”
In the 1980s, the president of Ichinokura, Kazuo Suzuki, went on a trip around Europe. In Belgium, he first tasted lambic beer that is very acidic and only mildly effervescent – more vinous and very different from the dry and refreshing lagers that are popular in Japan. In Vienna he then experienced the seasonal tradition of Federweisser (or Sturm as they say in Austria): Fresh low-alcohol wine that is still fermenting and therefore cloudy and fizzy. It is served, like beer, in small mugs, not wine glasses.
Inspired by these beverages that challenge our perception of what beer or wine can be, he wanted to create a new kind of sake that could transcend the established stereotypes at a time when sake was still seen as old-fashioned. This led first to the development of a refreshing low-alcohol sake and then the first sparkling sake, Suzune. The name Suzune refers to the tingling sound the small bubbles make in the glass.

Today, many types of sparkling sake are available, although only about a tenth of breweries in Japan have a sparkling sake in their lineup. The range includes sweet fizzy drinks with low alcohol content (5–7%), fresh and unpasteurised cloudy sakes, as well as a growing number of ambitious breweries that strive to produce dry and complex sparkling sake that can stand up to Champagne and other sparkling wines. Especially that last category has seen some interesting developments in the past few years.

Fresh and fizzy: Direct bottling

Let’s look at the most natural, almost coincidental, kind of carbonation first.

Carbon dioxide is a natural byproduct of the fermentation. Yeast converts sugar into alcohol and carbon dioxide - which is the gas that makes the bubbles. If the sake is handled very carefully and bottled quickly, it is possible to trap some of that CO₂ in the bottle.

If you’ve had a chance to try very fresh, unpasteurised sake (such as newly-pressed shiboritate at the start of the season), or a very carefully bottled muroka nama genshu [無濾過生原酒] (unpasteurised, undiluted and unfiltered sake) from a brand like Kaze no Mori, you may have noticed a pop! when you opened the bottle and a slight effervescence on your tongue. That’s because a small amount of carbon dioxide from the fermentation made its way into the bottle before it could dissipate. This sake is slightly effervescent, but not really sparkling like a Champagne.

Similarily, nigori sake, which is only filtered very roughly and therefore contains tiny rice particles and yeast cells that give it a cloudy appearance, is often lightly sparkling.

In fact, although Ichinokura Brewery is credited with inventing the first sparkling sake, Masuda Tokubei Shoten from Kyoto should also be mentioned. They were the first brewery to make (or rather, re-invent) cloudy sake after it had been prohibited for a long time. Their sparkling nigori sake is bottled while the fermentation is still active, which creates fine bubbles.

If a nigori sake has not been pasteurized and still contains active yeast in its sediment in the bottle, it is called kasseishu; the sake equivalent of vin bourru/Federweisser.

These types of sake are old and new at the same time. The brewing techniques might follow old customs, but before modern bottling and cooling technology became available, such sake could only be tasted for a short period of time directly at a brewery.

Examples: Freshly bottled sake needs to be kept cold and doesn’t keep well, so it is difficult to find outside of Japan. Look out for neck labels that say しぼりたて (shiboritate), 直汲み (jikagumi, directly bottled) or 荒走り(arabashiri, the very first liquid that runs from the mash-filled bags before pressing). Kaze no Mori’s slightly fizzy and fresh-tasting sake is available from Sake36 in Berlin. The already mentioned Tsukino Katsura Nigori is a classic example of a sparkling nigori.

How is sparkling sake made?

The types of sake mentioned above are often fizzy but that’s not really what we mean, when we talk about sparkling sake. So how is proper bubbly sake made?

Just like with sparkling wines, there are multiple ways to make sparkling sake, but they can broadly be divided in two categories: artificially carbonated or naturally carbonated.

Cheap and easy: Artificial carbonation

By far the cheapest and easiest way to produce sparkling sake is to simply add CO₂ to your finished brew. Imagine a giant soda maker that injects carbon dioxide into the sake.

Artificial carbonation is also how many cheap sparkling wines are produced. This method is not only easy and cheap, it also gives the brewers control over the exact amount of carbonation. But the resulting beverage will have relatively big bubbles that dissipate quickly.

It is also worth noting that carbon dioxide is considered an additive, so this kind of sparkling sake cannot be sold as specially-designated-sake (tokutei meisho shu), i.e. it must be sold as regular sake (futsushu) even though the base sake might have otherwise qualified as junmai (no added alcohol) or ginjo (made from highly polished rice). However, in international markets these terms are sometimes used regardless of the Japanese rules.

Examples: Mio from beverage giant Takara Shuzo is a fun and easy-drinking sparkling sake made with this method. In Japan you can find it in every corner store, in Europe it’s available at many Asian supermarkets or online. For a more refined bubbly, look for Keigetsu ‘John‘, a dry sparkling sake from Tosa Brewing Company based on their junmai daiginjo.

Under pressure: Natural carbonation

As mentioned, carbon dioxide occurs naturally during the fermentation and can be trapped in the sake if the container (tank or bottle) is tightly closed.

For sparkling wine, there are a number of techniques that are tied to certain regions and product names. These techniques are finely differentiated and regulated – whether fermentation happens in bottle or in a tank, whether carbonation occurs during the main fermentation (like Asti Spumante) or in a secondary fermentation etc.

In principal, all of the same methods used to make sparkling wine can also be applied to produce sparkling sake, but the categories are a bit more fluid. It is more difficult to strictly differentiate between the main fermentation (where the goal is to make alcohol) and the second fermentation (for carbonation).

Probably the easiest way to create natural carbonation is to simply bottle the sake as a roughly filtered nigori that still contains active yeast and enough sugars to allow the fermentation to carry on inside the bottle, thereby creating carbonation. The fermentation can be temporarily paused by lowering the temperature and will start up again when the bottling work is done and the temperature is raised. After the fermentation is finished, the sediment may be removed by filtration. This process is similar to méthode ancestrale, the production method for pétillant-naturel (pét-nat). If you remember, this is how Tsuki no Katsura Nigori (mentioned above) got its bubbles.

Producers of Champagne and other sparkling wines add a so-called liqueur de tirage, a mixture of yeast and sugar, to a still base wine in order to start the secondary fermentation. The sugar is needed to provide nourishment for the yeast, because the base wine is already fermented dry, with (almost) no sugar left.

But in sake brewing, addition of sugar is not allowed for special designation sake. So the brewers had to come up with a different way to provide nourishment for a second fermentation, using only the ingredients at hand. This process required a lot of trial-and-error to get right. Some breweries have worked for years to develop and refine their own recipe with the perfect balance that results in a good carbonation, the right alcohol level, and a pleasant flavour profile at the same time. Nagai Shuzo (known for the brand Mizubasho) have even patented their method.

One way to start the secondary fermentation would be to add a mixture of kasu and/or rice, rice koji (which will create sugar), water and yeast to a still base sake. The second fermentation can then happen in the bottle or in a tank.

At Masumi, they take a different approach and make two batches of sake that are then blended and bottled: one has been filtered and pasteurized, the other is only roughly filtered (nigori) and unpasteurized, with still-active yeast and microorganisms. The sediment is later allowed to settle in the bottle neck, frozen and removed, just like it’s done in Champagne (dégorgement), so the final sake is clear, without any cloudiness.

Examples: Nagai Shuzo’s Mizubasho Pure and the various sparkling offerings from Shichiken are excellent examples of Champagne-style sparkling sake available in Europe.

Sparkling excellence: Japan Awasake Association

Champagne has a reputation as the highest-quality and most prestigious sparkling wine and Japan is one of the world’s biggest importers of Champagne. So, of course, Japanese sake brewers wanted to create a sparkling sake to match.

A number of breweries have come together under the umbrella of the Japan Awasake Association in 2016 to further promote the development and sale of high-quality sparkling sake.

Together, they agreed on a list of strict rules to ensure a high quality (quoted here in original from their website):

• Created from only rice, rice mold and water. (Junmai and rice polishing ratio are not stipulated.)

• 100% domestically grown rice is used and graded above 3 by the Agricultural Produce Inspection Law as raw material.

• The preservation of only carbon dioxide which stems from the natural fermentation during brewing. (The second fermentation is within stipulation whether occurred inside the tank and bottle.)

• Outward appearance is clearly transparent and bubbles form after it is uncorked and poured.

• Alcohol content is 10% or more.

• Gas pressure is 3.5 bars (0.35 megapascals) or more at 20°C.

Furthermore, they state that aroma and quality should remain the same for three months or more at room temperature, and the sparkling sake must be pasteurised (hi-ire 火入).

The association has also trademarked the term awasake, at least in the mixed Roman-Japanese form “awa酒”, to further distinguish their products from the many mass-produced sparkling sakes on the market.

Breweries have to document their brewing process and the raw materials they use, and are inspected twice a year to ensure that all regulations are being followed. The finished product is also inspected by external laboratories that measure gas pressure, alcohol content, and even the composition of the carbon dioxide (to ensure that no artificial CO₂ was added). If a product meets all standards, the bottles are marked with a hologram seal that guarantees the authenticity and quality of the awasake.

With this push for premium quality, the Awasake Association wants to clearly distinguish their products from the many rather simple and sweet-ish sparkling sakes at the lower end of the market, some of which can also claim to be naturally carbonated (often via second fermentation in tank).

Despite the strict rules, there is a lot of stylistic variation among the Association member’s products. Hakkaisan from Niigata produces a clean and elegant awasake that fits very well into their portfolio of classic Niigata-style sake, while Shichiken has experimented with ageing in used whisky barrels from Suntory’s Hakushu Distillery to create complex and luxurious sparkling sake.

In Europe, the selection of high-quality sparkling sake is still quite small, and even bigger brands can be difficult to find – but that will certainly change as sake in general becomes more popular all over the world. Nagai Sake's president Noriyoshi Nagai hopes that “one day, people all over the world choose sparkling sake to make celebratory toasts.”

Cheers to that!

Thanks to bottling specialist Kita Sangyo Co. Ltd. for their extensive library of sake-related data, which was an invaluable resource for this article.