Back in the olden days, when life was hard and resources were scarce, brewers often did an odd thing: they boiled their worts for insane lengths of time. The Belgians seem to have been kings of the long boil: an average wort would spend four to six hours in the kettle, and some ranged upward—way upward—from there. Take, for example, the case of the bières brunes des Flandres, described by the brewer Georges Lacambre in 1851:

“Boiling of these beers is longer and stronger than uytzet: commonly the boiling of these beers is 15 to 18 and even 20 hours in many breweries. The aim here is especially to colour the beer, as well as [adding] stability and the special flavor that the wort gains by this long boil.” (Translation by Randy Mosher, from a wonderful resource that is no longer on the Internet.)

Put yourself in the mind of the 19th-century Belgian brewer. You work without benefit of most modern tools of brewing and confront an almost entirely manual process. Thanks to strange tax laws, you use an unnecessarily convoluted mashing process that adds hours onto the brew day. (In describing the white beers made in Leuven, his home town, Lacambre identifies five separate vessels used in mashing.) So after all that, you then spend the better part of a day and a ton of wood or coal to conduct a boil that will leave you with some small fraction of the wort you started with? Madness!

There had to be a reason. I have always assumed it lies in that “special flavor” Lacambre mentions (but, frustratingly, does not describe). Is this a new flavor you only get from long boils, or the intensification of pre-existing flavors? Are the flavors good or just odd? Is it really worth the time? Belgians weren’t the only ones who conducted long boils—the British were known to do it as well, so I couldn’t chalk it up to Low Country quirkiness. But lacking any first-hand evidence, this strange practice and has remained filed in my brain in a folder marked, “for further research.”

Van Havig Ben Love
Van Havig and Ben Love of Gigantic Brewing. Photo by Jeff Alworth

It has remained there gathering dust until—hosanna be to the beer gods!—a couple weeks ago, when I finally feasted my eyes on one of these beery dinosaurs. For the second year in a row, Gigantic Brewing Co. fired up the kettle and let it roar for nine hours to make a beer it calls, modestly, Massive! For those outside the Pacific Northwest, Gigantic was formed by two veteran Portland brewers: Ben Love (Brewmaster), who left Hopworks, and Van Havig (Master Brewer), who left the Portland Rock Bottom. They have only one year-round beer, and everything else is released just once—or in the case of Massive!—annually. But as ambitious as many of their beers have been, none has yet topped this crazy 12% English-inspired barley wine.

Gigantic Massive
Gigantic Brewing’s Massive! was brewed for nine hours. Photo by Jeff Alworth

We’ll get to that “special flavor” in a minute, but first a note on the color. For the initial batch, Love and Havig used 100% Halcyon, an English floor malt. (Their inspiration was not Flanders but the strong-ale brewers of the Midlands.) For this year’s batch, it was Golden Promise. When I received a snifter of the stuff at the brewery, I was startled by how dark it had become. Even expecting some change, I imagined an orange or amber hue. Havig acknowledged my surprise: “Welcome to my good friend, Mr. Maillard.”

Over those nine hours, the wort loses about a third of its volume, which concentrates the malt. But more importantly, the malts go through a process known as a Maillard reaction that browns them. (It involves carbohydrates and amino acids and chemistry that I don’t fully grasp.) You can see in the photo how brown the beer actually got, and that’s not a trick of photography or lighting—it was a very deep color.

But the color is merely the carnival barker trying to get you into the tent: the real show comes on the tongue. During Maillard reaction, hundreds of compounds are formed, and collectively they tend to give a meaty, umami flavor in foods. In this beer, though, they produced a dazzling range of dried and candied fruit flavors. They reminded me a bit of the fruitiness some yeasts produce, but they were much more intense. In our folk understanding of beer, we say that an open flame “caramelizes” the wort, but that’s not accurate. Caramelization is a different process that requires hotter temperatures. And in this beer, you could really tell the difference—there wasn’t a note I could find that tasted like toffee or caramel. It was all dates and cranberries and figs and strawberries.

There were two other characteristics of note. I picked up a flavor that reminded me of the kind of subtle oxidation that produces sherry-like notes in aged strong ales. It wasn’t exactly oxidation, though, and tasted strongly of a well-made ruby port. The second was the texture, which was not only velvety and thick—you’d expect that in a 12% barley wine—but more honeyed and viscous than any beer I remember drinking. It was so thick I imagined that if I swirled it around my mouth long enough, it would eventually collect into a gummy ball. (We can put that experiment back in the “for further research” file.)

So, there you have it—the “special flavor.” It is not a contemporary flavor per se—modern beer fans like lighter, drier, crisper flavors—but it might be poised for at least a niche comeback. We like strong flavors in our beer, and Massive! is loaded with them. And there’s no way to get that special flavor from one of those evanescent little 90-minute boils, either.

RELATED: Randy Mosher on The Many Splendors of Malt

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Jeff Alworth is the author of the forthcoming book, The Beer Bible (Workman, 2015). Follow him on Twitter or find him at his blog, Beervana.