Gritty McDuff’s brewpub, with locations in Auburn and Portland, started making its Christmas Ale in November in preparation for the holiday season.

The blue-gray dawn brings out the rich red of brick Nov. 22 in the Old Port. It’s an unusual hour to be at a pub. Larry Hudson has been working since 6 a.m. to start the last batch of Gritty McDuff’s Christmas Ale. And he hasn’t even had a sip of his coffee yet.

Hudson empties a 55-pound bag of pale malt grain that will be fed it into a mixing tank with water. One batch of Christmas Ale requires 502 pounds of grain. Two batches of brew will be made this season. Hudson has been making Gritty’s beer for nine years.

The different types of malt are distinguishable by their shade as they are emptied into a tank from the hopper.

Roasted chocolate is one of six types of grain in the Christmas Ale. To achieve the 6.8% ABV (alcohol by volume), the beer requires a larger quantity of grain — in fact, almost double — than lower ABV brews.

Once the grains are added, the tank is topped off with water and the mixture is heated to 168 degrees. “I take a sauna every morning,” Hudson jokes, visibly sweating from the steam rising from the tank. The metal is hot to the touch. Occasionally Hudson will burn his hand if it slips while stirring the mash with the paddle.

Hudson uses a tape measure to calculate the water feeding into the beer tank. Each inch accounts for 6 gallons of water.

Hudson tracks the process in a ledger. The job of a brewer is equal parts physical and mathematical, as it requires balancing ingredients, monitoring conditions, and physical strength for pouring, stirring and scrubbing.

The refrigerated room, where beer is stored, offers a welcome respite after Hudson spent the last hour making mash. Hudson has been a brewer for 32 years, not counting the craft brewing he started as a hobby when he was working as a global shipping company manager. He describes himself as more mellow than he was in earlier days. He worked at Geary Brewing Co. for 23 years before coming to work at Gritty’s.

The fermentation process leaves coffee-colored remnants in the tanks, so the tanks must be sanitized before a new batch of beer is added. “Sanitation is the No. one most important thing,” Hudson said. “Otherwise, the beer can get infected.” The tanks contain liquid beer as it ferments with a thick, frothy layer produced by a 200-year-old yeast strain, making Gritty McDuff’s one of only three breweries in the U.S. to produce the truly traditional English-style ale.

With a clean tank ready to go, it’s back to the batch of Christmas Ale that is taking shape. Brightly colored and bitter in smell, these pelletized hops are going straight into the brick kettle brewing system.

It’s roughly 2.5 hours into the process and the most strenuous part has been completed. Now it’s back to the books.

Making beer involves a lot of math and measurements: by weight, height, temperature and time, as all the ingredients and their conditions need to be in balance in order to make the right quantity and flavor of the brew.

Another stage of heat is starting, as flames warm the brick kettle brewing system where Hudson prepares to transfer the mash to the kettle via pipes and the smaller quantity of ingredients will be introduced. Using the copper-topped kettle makes the temperature inside the brewery rise considerably.

Hudson recirculates wort, which is liquid malted barley, into the mixture to add sugar and break up clumps that may have formed. It’s part of what will become 215 gallons of Christmas Ale in this batch alone.

Holding tanks in a refrigerated room contain the finished beer — including the first batch of Christmas Ale Hudson monitors the tanks for the brewpub to keep track of what’s available for pouring for the public. Between starting fresh batches of beer, sanitizing tanks and maintaining ingredients and finished products, Hudson comes to Gritty’s almost every day of the week.

The traditional English-style beer conditions for 10-12 days before it ever enters the glass of a customer. It’s been brought up in kegs from Portland to Gritty McDuff’s Auburn location, and the tap handle is topped with a miniature brick kettle brewing system. Some beer is made in Auburn, but the Christmas Ale was made in Portland.

Bartender Bob Hoye pours a pint of Christmas Ale Dec. 8 in the Auburn taproom. “It’s one of our most popular beers,” Hoye said.

It’s not a product that can be found on store shelves because it’s not bottled. The Christmas Ale can be ordered on tap at either Gritty McDuff’s location, in Portland’s Old Port or in Auburn at the corner of Main and Court streets.

A pint of Christmas Ale, one of a little less than 400 gallons that are available this season.