Crossing Cultures: Making a True Sake-Beer Hybrid

For the last five years, I have collaborated with the brewers at the Cambridge Brewing Company in Massachusetts to make a sake-beer hybrid. The idea of marrying sake and beer has been around for a while, but a hybrid has never been made in any great quantity. One of the issues with the idea in general is that many brewers, in spite of their creativity, do not have any experience with sake. To help define what a sake-beer hybrid is (or could be) let’s first look at how sake is brewed.

Sake is an alcoholic beverage made from rice with a history that stretches back thousands of years. Its origins can be traced to ancient alcohol that was made with a variety of grains and nuts, chewed in the mouth, and fermented. Starting roughly 2,500 years ago, when the Japanese people were introduced to rice cultivation through trade with China, they applied this chewing technique (kuchi kami 口噛み) to rice and it worked well. This is because human saliva contains an enzyme called amylase that converts starches to sugar and allows for fermentation by wild yeasts. All alcohol is made by yeast fermenting sugar, but, in the case of rice, the sugar is harder to get to. Wine grapes have sugar readily available to the winemaker; barley can be malted to access the sugars with enzymes. Rice, however, isn’t naturally sweet like a grape and cannot be malted like barley because the outer layer is removed during a necessary polishing stage.

A few centuries later, brewers introduced the techniques of growing and using a second microorganism, koji (Aspergillus oryzae), to brew cleaner sake with more control. It is the delicate balance between yeast and koji that is the hallmark of modern sake brewing and which sets it apart from many other alcohol methods. This unusual method enables simultaneous “malting” and fermentation in the same vessel, a process known as multiple parallel fermentation.

As the koji enzymes produced by the fungus grown on some of the rice slowly convert the remaining rice in the mash to sugar, the yeast ferments those sugars into alcohol. This type of fermentation also poses a unique challenge: once the sake is done, how do you remove the hundreds of pounds of solid material in the brew? Methods range from putting the mash in cloth bags pressed with weight to using high-tech filter presses. After clarifying, the sake is very delicate and susceptible to oxidation and spoilage. To preserve its quality, sake breweries will pasteurize most of their product, often twice.

New Frontiers in Beer
In my opinion, a beer made with rice added is not a sake-beer hybrid. More than a few brewers use short grain rice (or rice syrup) in their recipes and, for the sake of marketing, link their beer to sake. Since rice has long been used in beers—chiefly by larger macro breweries—I don’t think that rice alone is enough to qualify any real connection to sake brewing.

A hybrid of two or more things should contain elements of each and represent a composition derived from the disparate parents; therefore, a sake-beer hybrid should contain essential elements from both beer and sake. How this is done is up to the brewer. There are obviously varying degrees of commitment.

Koji is arguably the most important ingredient in sake. Not only does it convert all of the starches to sugar for fermentation, it also lends a unique flavor. Used for centuries in products like miso and soy sauce, as well as in other fermented foods like pickles, it brings a quality to beer unlike any other. The added benefit of using koji is that the enzymes will further convert barley sugars, yielding a higher gravity and an earthy dryness. Recently the Australian Brewery in Sydney made a lager with koji, hoping that it would add earthy notes to the brew. “The initial mushroomy character was immense,” says head brewer Neal Cameron. Despite backup from earthy Fuggles hops, the mushroom notes of the beer—dubbed Koji—unfortunately didn’t stick around. Knowing that there is a great beer in there somewhere, Cameron continues to work on it.

In most alcoholic beverages, yeast is the unsung hero providing most of the flavors and aromas; in sake it is no different. Sake yeasts are a cold loving offshoot of Saccharomyces cerevisiae. During primary fermentation with a sake yeast, temperatures should not exceed 59°F (15°C). This “low and slow” method produces a super clean, fruity and expressive brew with remarkable aroma character. Since these yeasts are fermenting in a 100 percent rice brew, off flavors have nowhere to hide.

Recently the Brewers Association added Japanese Sake-Yeast Beer to their style guidelines. With the beer attributes kept broad, this style stresses a harmony with the sake yeast (and/or koji) to highlight these special techniques. One of the most successful examples is the Red Horizon series from Nøgne Ø Brewing in Norway. Because co-founder and brewmaster Kjetil Jikiun fell in love with sake just like he did with craft beer, Nøgne Ø is one of the only breweries outside of Japan that brews both. Red Horizon is a huge (12.5 percent ABV and 100 IBU) and constantly changing beer that nevertheless manages to highlight the fruity complexity of sake yeast. “I thought that the combination between these delicate aromas would be interesting balanced by a full bodied malty mouth feel,” notes Jikiun. Fermenting at low temperatures for around six weeks, Nøgne Ø manages to pull off an exceptional beer that can only be described as a “Sake Barleywine.” Consumers praised its sake-driven attributes, and Jikiun agrees with their assessment, “I usually say that our sake-beer hybrids have the flavor of beer, but the nose of sake. The fact that these yeast strains are very alcohol tolerant makes them fun to work with, too.”

In the last few years, a few one-off beers have used both koji and sake yeast. As recently as 2008, Vermont’s Otter Creek Brewing released a beer called Otter-San. Only brewed once and made with Pilsner malt, rice, Hallertau hops, koji and sake yeast, this beer was well received and flavorful, but was brewed as part of a series of one-off “World Tour” releases. Lately, a few larger brewers like Goose Island (Kisetsu Ale) and Japan’s Yo-Ho Brewing (“Sorry” Ale) have experimented with koji and sake yeast; unfortunately, these brews have also only been brewed once.

The Birth of Banryu Ichi
After searching high and low and talking to many brewers on both sides of the Pacific, I can only find one sake-beer hybrid that meets my interpretation of hybrid. It’s a beer I make with CBC’s brewmaster, Will Meyers. Five years ago, we started experimenting to find a way to brew a real hybrid that was just as much sake as it was beer. “We experimented with different ways of making this hybrid,” Meyers remembers. “We wanted to make it in such a way that the unique organisms and chemistry in both sake and beer were fully highlighted.” We brewed several small batches to test different ideas, but settled on brewing a whole batch of sake and using it to inoculate a tank of heavy wort containing some rice. “I wanted the experience of actually brewing sake to further understand that brewing process. I needed that knowledge to make an authentic hybrid with beer,” says Meyers.

Sake yeast typically starts to get sluggish when the alcohol by volume level reaches 18–20 percent; however, if its environment is diluted with beer wort, the yeast “wakes up” and ferments the whole thing in a cold, six-week period. Using fresh fermenting sake, we are able to ferment a 300-gallon tank of rice-laden wort. One of the keys to this beer is that the koji enzymes further break down barley sugars, giving us a dry, complex beer from a wort that would usually produce a heavy, malty beer. We call this beer, which we brew each winter, Banryu-Ichi, meaning “10,001st way” after an old Japanese saying that there are 10,000 ways to brew sake. Not many breweries have the ability to brew a whole batch of sake before experimenting with a new beer, but luckily Meyers and CBC relentlessly push the boundaries of beer. So far it has been a hit. “Steaming the rice and making sake at the CBC was quite a spectacle that not only got our customers interested in sake, but also brought in new sake-focused customers who also tried our beers,” Meyers says.

With variety and new styles driving much of the growth in the beer market, I hope more brewers turn toward sake as a source of inspiration. While I don’t expect many to be able to work with a sake brewer, I do hope that craft brewers will first get to know sake by buying it, reading about different sake styles, or attending a sake tasting. By respecting Japanese brewing and using sake-brewing ingredients and techniques, we’ll take beer to new and interesting places. ■