WESTBROOK, Maine — Eggnog won’t cure what ails you, but it just might diminish the stress of the holidays one creamy sip at a time.

This wintertime milk punch that was a celebratory must in Colonial times is still made the old-fashioned way on a dairy farm in Westbrook.

Once a year, the dairymen at Smiling Hill Farm take a break from producing chocolate and blueberry milk to concoct their secret eggnog recipe.

“It’s time consuming. The guys hate it,” said Warren Knight, who runs the 500-acre farm with his siblings a few miles outside Portland where office parks slowly yield to the countryside.

But they do it because the taste is sensational, said Knight.

“If you’ve never had eggnog, it just says Christmas. It just says family.”

And lately, it’s been in demand.

Last year, Smiling Hill sold out of its eggnog early. Made in small batches with all-natural ingredients and poured into glass bottles moments after it’s made, the golden drink is akin to liquid ice cream. Like a rich ragout, it takes time for the tastes to marry.

“You want to give it a few days,” Knight said.

One evening last week, a team of workers mixed the eggnog into an industrial tri-blender. The gentle process, which requires low speed and careful monitoring, is time and temperature sensitive. And every batch is different, said Knight, overseeing the 1950s technology dependant on conveyor belts and men in hairnets, beardnets and rubber boots.

The micro dairy makes in a year what a giant such as Oakhurst Dairy in Portland does in a day. But thanks to the slow food movement, slow eggnog is catching on.

What makes Smiling Hill’s nostalgic drink — delicious spiked, virgin or splashed in coffee — so luscious?

It’s in the numbers.

They start with whole milk, which clocks in at 3.25 percent butterfat or higher. Next, they add heavy cream.

“I’m not going to give away the formula,” said Knight, revealing only that spices are mixed with yolks and cane sugar. Knight is most proud that high fructose corn syrup doesn’t come into play here.

According to Frederick Douglass Opie, author of Hog and Hominy: from Africa to America,” the origins of eggnog are semantic: “Colonists referred to rum as grog; bartenders served rum in small wooden carved mugs called noggins … Thus the drink eventually became egg-n-grog and over time eggnog.”

No matter what you call it, if you make eggnog at home, let it set for 24 hours for optimal taste, said Knight.

“It gives it a chance for it to set up,” he said. “There are certain products that meld better after time.”

He grabs a bottle from a refrigerator at his cafe for an impromptu taste test. The first sip transports me to a Dickens’ Christmas scene. It’s rich, full and holiday-y. With a hint of vanilla, it’s well-rounded and nourishing. Almost healthy in its festive, wholesome way.

Moments later, we visit the barn with eggnog production in full swing. Offering a sample of the minutes-old nog, the point it clear. It’s a thin, less robust facsimile. But in a few days it will taste every bit as deluxe as its double digit butterfat count. “You don’t want to drink this every day,” said Knight, who grew up on the stuff despite his lean frame.

“When people drink it, it brings back memories, both good and bad,” Knight said as he downed a cup.

The Knights started making eggnog 20 years ago. True to tradition, it began with the family seated around a table sharing recipes.

So why does this nog taste so good?

“We don’t corn-raise our cows,” said Knight. “They are pasture raised, and you can taste it in the milk.”

Smiling Hill Farm eggnog is sold at Shaw’s and Hannaford in Southern Maine, at stores like Spring Brook Farm in Cumberland and at their dairy store open from 9 a.m. to 6 p.m. every day. Prices range from $2.49 for a pint to $4.79 for a half gallon.

Four things you don’t know about eggnog

• Use your noggin: A nog is any milk-based drink historically served in wooden cups. A small block of wood is called a nog.

• Drink to your wealth: In the winter, the aristocracy drank a warm milk and egg beverage seasoned with pricy spices such as nutmeg and cinnamon and spiked with brandy or sherry to keep it from spoiling. Commoners went without.

• It was only made once a year because milk and cream were luxury items and spices like cinnamon or nutmeg were rare.

• A 16-ounce eggnog latte from Starbucks is 460 calories.

— Compiled from Warren Knight, Fred D. Opie and Starbucks.com.

Kathleen Pierce

A lifelong journalist with a deep curiosity for what's next. Interested in food, culture, trends and the thrill of a good scoop. BDN features reporter based in Portland since 2013.