The call, as Jim Koch remembers it, came in October 2007. “Frankly, I though it was a prank,” says the founder and chairman of Boston Beer Co. But the voice on the line was actually Dr. Joseph Schrädler, managing director of Bavaria’s Weihenstephan Brewery, which traces its founding back to the year 1040. “We have seen what Sam Adams has done with innovation,” said Schrädler, who invited Koch to collaborate on a beer – a totally new style – that he hoped would inspire innovation and help jump-start a moribund beer industry in Germany.
The crucial insight was that Mother Nature was a frugal as she was provident.
“The world’s oldest brewery was reaching out to a guy who was making beer in his kitchen 26 years ago,” thought an amazed Koch.
Thus began the partnership that led to Infinium, a beer that stretches the frontiers of brewing science and raises the philosophical question: can you call it a new “style” if it’s the only one of its kind in the world?
At the time, nether Koch nor Schrädler had an inkling that this mission would last three years, tax the ingenuity of master brewers on both sides of the Atlantic, and require them basically to throw away the textbook on beermaking and turn the normal brewing process on its head.
From the outset, Koch and his collaborators at Weihenstephan had a basic idea of what they wanted to brew. As Koch describes it, it would be “a champagne style of beer, strong, but not cloying or thick, dry but not thin, highly carbonated.” It would occupy a “white space” in the spectrum of German beers that had never before been occupied.
Koch originally envisioned a beer 15-18% alcohol by volume. “But if you make a beer that high in alcohol, it’s like a spirit or liquor,” commented Weihenstephan brewmaster Frank Peifer. “The high fermentability combined with thin body is not good for the complexity.”
The parties agreed on alcohol content of 10%, which is still stronger even than most German doppelbocks.
For an American brewer, making such a beer would be a piece of cake. He’d simply replace part of the grain bill with high-fructose corn syrup, a substance that yeast cells gobble up as greedily as junk food addicts do Twinkies. A Belgian brewer might use candi sugar to brew a tripel, a beer that manages to be elegant and light on the palate in spite of an 8-9% alcohol-by-volume content.
However, Koch and his Weihenstephan colleagues were bound by the Reinheitsgebot (“purity law”), a 500-year-old diktat that limits the ingredients in brewing to a basic four: barley malt, hops, water and yeast. Adjuncts and artificial enzymes are strictly forbidden.
Sometimes, a conundrum in brewing can be solved by the substitution of single ingredient. And Weihenstephan has one of the world’s most extensive yeast banks. According to Peifer, It includes a mutant ninja strain called Saccharomyces diastaticus, which is capable of fermenting complex carbohydrates that would give ordinary yeast cells indigestion.
That was rejected for two reasons. First, says Peifer, “the flavor was not very nice” in the test batches. Secondly, there was the danger of cross-contamination. If S. diastaticus took up residence in a batch of Samuel Adams Boston Lager, for instance, it would begin devouring the residual sugars, turning the beer cloudy and possibly exploding the bottles.
Scratch that one.
Koch and his team tried different malts at different temperatures, using long, decoction-style mashes to break down the cell walls in the grain and allow the natural enzymes in the barley to convert the starches to sugars more efficiently.
“We made slight incremental improvements, half a percent of alcohol at a time,” Koch recalled. He and the Weihenstephan brewers were able to raise the RDF (real degree of fermentation) to 68%… meaning that the yeast was converting 68% of the dissolved sugars into CO2 and alcohol. But that meant “we were leaving about a third of the fermentable material in the beer,” he added. Koch estimated that they would have to get the RDF to near 80% to brew the kind of beer they wanted. Their goal was still a long way off.
“There were lots of dead ends. It took two years to get a breakthrough.”
That breakthrough, he remembers, came not with shouts of Eureka! or a light bulb flashing over the head, but the gradual dawning that “you couldn’t get there through the conventional framework of brewing.”
The crucial insight was that Mother Nature was as frugal as she was provident. “’Wait a minute!’ we thought. The stuff wouldn’t be in the grain if the grain couldn’t break it down into sugars that the embryonic plant could use. The whole purpose is give the plant energy to grow. And if the plant can get to it, the yeast ought to be able to.”
The problem lies in the malting process, which greatly speeds up what happens when barley grains are planted in the earth. At the malthouse, barley is steeped in water until the grains sprout, after which they’re kiln-dried at temperatures of 130 degrees Fahrenheit and higher. The purpose of malting is to unleash naturally occurring enzymes that will be needed to convert starches into sugar for the yeast to use.
The maltster accomplishes in about four days what would take Mother Nature a month. But what he gains in time and efficiency, he loses in diastatic power… the ability to generate those all-important enzymes. Part of these chemicals are broken down by the unnaturally high temperatures during the malting process. (In fact, highly roasted malts, the chocolate and black patent malts that lend beer a deep ruby-red or mahogany color, have lost their diastatic power completely. Even the darkest stout must brewed with a grain bill of mainly pale malts; otherwise, no sugar would be produced for fermentation to take place.)
What if we could replicate the conditions in nature, Koch and his brew crew wondered, and do a longer germination at lower temperatures to modify the malt fully?
The first step was to contact Bruno Vachon, owner of Malterie Frontenac, a small specialty malting house in Thetford Mines, Quebec. “They didn’t really know what they needed,” recalls Vachon, who studied at the Doemens Institute, another prestigious German brewing academy. “We made tests of various grains, and looked at ways of maximizing the enzyme content. We pushed the envelope the way we steeped the barley, the way we germinated it, the way we dried it.” The result was a very underkilned pale malt, much like German Pilsner malt, but with two or three times its diastatic power. “We made in the neighborhood of 50 tons,” says Vachon, a huge chunk of business for a maltery that produced about 300 tons altogether last year.
(Ironically, he noted that he hadn’t yet tasted the finished product. “Infinium wasn’t available in our part of Canada and I haven’t been able to cross the border to get some for myself.”)
The special malt wasn’t enough to ensure success. Mashing, that part of the brewing process in which the grains are mixed with water and heated to temperatures of about 150 degrees, can also break down the enzymes. Koch and his cohorts turned the normal brewing regimen on its head. They removed a portion of the mash—dubbed the “supernatant”—and allowed the conversion of starches to sugars to proceed at typical soil temperatures—between 60 and 80 degrees. At those temperatures, the process slowed to a relative crawl. “The normal mash time is two hours,” observed Koch. “We needed 300 times that.” (Do the math – that equals 25 days!)
“You can’t tie up your mash tun for weeks,” note Koch, so this leisurely conversion took place in a fermenter—normally the vessel where beermaking concludes, not where it begins.
The rest of the mash (Koch wouldn’t say how it’s divided up—the exact percentages are proprietary) goes through the regular brewing process, receiving a kettle addition of noble hops (mostly the same Hallertau Mittelfrüh hops that go into Sam Adams Boston Lager). It’s then combined with the supernatant in the fermenter. “We started it with the Sam Adams ale yeast that produces a lot of fruitiness,” noted Koch. After a primary fermentation of “a few weeks,” the brewers added a second yeast (also top-fermenting) bred to work in a high-alcohol environment. The beer also received a dry-hopping with noble hops.
Up to this point, Boston Beer Co. and Weihenstephan had been brewing parallel batches, swapping note with one another, Here is where the two beers diverged. Koch transferred his version of Infinium to Pleasant Valley Wine Company (maker of Great Western Champagne) in Hammondsport, NY. There a final fermentation was sparked in the bottle to naturally carbonate the beer. The beer went through the methode champenoise, which involves “riddling” the bottles (rotating them with the cork pointed downwards) and removing the spent yeast from the bottleneck through a process called degorgement.
In Weihenstephan, the final fermentation took place in the same stainless steel tank that the brewery uses for its Hefeweissbier. “It’s Germany!” laughs Koch. “Everything’s over-engineered there.” The pressure that builds up as the beer is carbonated would have ruptured his own vessels, he adds.
Neither Koch nor Peifer believes the difference in procedure had any significant effect on the flavor.
At last, more than three years after the project began, Boston Beer shipped out about 200,000 of the 750-ml gold-embossed bottles of Infinium to retailers across North America.
As an exercise in problem-solving, Infinium was a success. But how does it taste?
Infinium is much less a departure from normal beers than was Utopias, the 27% alcohol-by-volume behemoth that resembled a cognac or whiskey more closely than a beer. It has a delicate, fruity flavor with notes of peach or strawberries; one of my fellow tasters detected a hint of kiwi fruit. There is, however, a sweet, almost sugary malt backbone that identifies it as a grain-based rather than grape-based beverage. The effervescence is brisk, and the beer hides its 10.3% ABV alcohol content well; there is no “hot” taste in the back of the throat. If Boston Beer decides to repeat this beer next year (and Koch says he will, with a few tweaks to enhance the fruitiness), it would make a fine substitute for Dom Perignon to ring in the New Year for 2012.
According to Peifer, Weihenstephan would like to brew the Infinium several times during the course of the year, exporting it to 41 countries (basically, all the world except for the U.S. and Canada). He said that he’d like to work with Koch and Boston Beer Co. again, but added, “The next time, the beer will be something entirely new.”