Kathleen Nyberg / Submitted photoRevelers at last years High Gravity Extravaganza were kept warm by blazing firepits and the wide selection of strong beers on offer.

There’s a reason they call Central Oregon the High Desert — it’s dry. Very dry. But parched locals and visitors can drop into the third annual High Gravity Extravaganza on Saturday at McMenamins Old St. Francis School in Bend for some liquid refreshment from 25 Northwest breweries and cideries, plus great live music.

This year’s High Gravity Extravaganza seems set to live up to its slogan, “Go big or go home” with a different high gravity beer from 10 McMenamins locations. Twelve other Central Oregon brewers are also participating, including Crux Fermentation Project, Sunriver Brewing Company, Ochoco Brewing Company, Deschutes Brewery, GoodLife Brewing, Boneyard Beer Company, RiverBend Brewing, Wild Ride Brewing, Three Creeks Brewing Company, Worthy Brewing, Silver Moon Brewing and Bend Brewing Company.

Attendees can choose from a wide selection of high-gravity beers ranging from porters and stouts to red ales, pale ales and barley wine. And for the first time this year, cider will also be served with Far Afield Cider, Atlas Hard Cider and Red Tank Cider joining the fun.

Although geographically apt, the High Gravity portion of the event title isn’t a reference to Bend’s altitude or the laws of physics. It’s actually a brewing term that describes the relative density compared to water of each beer’s “wort” — that’s the sugary liquid produced by grains during the brewing process. A beer’s original gravity is a measure of the fermentable and unfermentable substances in the wort prior to fermentation. It is typically considered high gravity if the original gravity measures above 1.075 on a hydrometer.

When it comes to beer, higher gravity results in higher alcohol content and bolder and more complex flavors, because there’s more sugar for the yeast to consume during fermentation. Some ciders also have a high original gravity, but generally have a lower final gravity and lower alcohol content than high-gravity beers.

With the potentially greater rewards of high-gravity brewing, however, come greater risks of problems such as stuck fermentation. This occurs if the yeast becomes dormant before all the available sugar has been converted to alcohol and carbon dioxide, which can cause the brew to be spoiled by bacteria and oxidation.

Tony Lawrence, co-founder and brewmaster at Boneyard Beer in Bend, points out that brewing high-gravity beers requires more supervision than many other beers. “You have to keep a close eye on things and be ready to make adjustments quickly if you notice fermentation slowing down too soon,” said Lawrence.

“If you catch problems early, you can raise the temperature or add yeast to try and rouse the process, but once fermentation has stopped it’s almost impossible to restart it,” he said.

How far fermentation has progressed before getting stuck determines whether or not the resulting beer is salvageable. If it happens early in the process, the entire batch may have to be dumped. If things have progressed further, the beer may be drinkable but will have a lower-than-hoped alcohol content and be sweeter than planned due to the unused sugar that remains in the brew.

McMenamins Old St. Francis School brewer Mike “Curly” White, one of the High Gravity Extravaganza’s founders, notes that many participating breweries either create a special high gravity beer just for the event or will modify and customize an existing product.

“Everybody’s experimenting and pushing the limits right now, and the Extravaganza is a great place to showcase that,” he said.

“We do an event like this in the middle of January because bigger, bolder beers are what people are gravitating toward this time of year,” White continued.

White has brewed a double black IPA called Midnight Scream with 7.2 percent alcohol by volume for the event. He roasted blackprinze malt to give the beer a nice dark color without too much bitterness or astringent flavor, and also mixed in some chocolate malt. He used a little more hops than usual and then dry hopped the brew in the secondary stages to give it a more aromatic, IPA taste and feel while still getting the roundness of a big, black beer.

McMenamins tapped some of the Midnight Scream the week before Christmas, and it was so popular White had to make a second batch to ensure there would be enough left for the Extravaganza. If the response continues to be so positive, White said, Midnight Scream may become a recurring seasonal beer at McMenamins.

Boneyard Beer’s Extravaganza entry this year is its Notorious triple IPA, which clocks in with a substantial 11.5 percent ABV. Boneyard’s Lawrence said, “This beer is all about the hops. The malt is just there for the hops to stand on.”

He used a combination of mosaic and citra hops, and pitched around twice as much yeast as he would use with lower alcohol beers, in order to consume all the sugar needed and achieve the alcohol content he wanted.

One high-gravity brewing technique Lawrence used when making Notorious was the inclusion of dextrose (corn sugar) in the wort. He says it helps because the yeast can metabolize dextrose more easily than some other more complex sugars, helping avoid stuck fermentation.

Any Celts out there may enjoy the Scottish Heart Scotch Ale being poured at the event by GoodLife Brewing. This is a seasonal beer GoodLife releases each year to coincide with St. Andrew’s Day on Nov. 30 (St. Andrew is the patron saint of Scotland). It’s a caramelized, malt-forward ale with 8 percent ABV.

From 1 to 4 p.m. representatives from many of the participating breweries will be on hand to answer questions. Attendees at the Extravaganza can also vote for their three favorite beers in the People’s Choice award. The winner will be announced at the event and have bragging rights for the next twelve months.

The Extravaganza isn’t just about beer. At 3 p.m. Portland-based neo-soul band Dirty Revival will take the stage inside. This seven-piece outfit recently released its self-titled debut album and will perform a mix of original tracks and soul favorites.

Musical headliner Sophistafunk is due onstage at 7 p.m. with a unique blend of funk, hip-hop, spoken-word and live analog electronic sound. The trio from Syracuse, New York, is composed of vocalist Jack Brown, Adam Gold on keyboards, bass and backup vocals, and Emanuel Washington on drums. Their sound has been compared to Rage Against the Machine, The Roots and even Herbie Hancock.

The High Gravity Extravaganza is open to all ages. Guests can enjoy their beer and cider beside the roaring fire pits outside, or shed their coats and relax inside. Admission is free and tasting punch cards cost $15 for 10 punches or $1.50 for individual tastes. Food is available for purchase.

— Reporter: 541-383-0350, khimstreet@bendbulletin.com