PITTSBURGH — Shorter days. Cooler nights. And more — lots more — beers to pick from.

The advent of autumn and the holidays that follow brings a flood of seasonal beers to market, from pumpkin spice ales to Oktoberfest and yuletide brews. This, of course, follows a long hot season of wheat, blueberry and other summer beers.

But it turns out seasonal beers, the latest popular offshoot of the craft and micro-brew phenomenon, isn’t all that new.

“Christmas beer is a tradition that actually predates Christmas, frankly. It goes back to the earliest days of brewing,” says Don Russell, a beer writer who’s just written “Christmas Beers: The Cheeriest, Tastiest and Most Unusual Holiday Brews.”

“Whatever holiday was going on, brewers would have made special beers for that holiday,” he says. “You wanted to mark the occasion with something special.”

But in recent years, breweries large and small have rolled out seasonal beers.

“About a year ago is where we saw seasonals pass pale ales as the number-one growth in craft beers,” said Paul Gatza, director of the Brewers Association, a trade association in Boulder, Col., with about 1,100 brewer members.

Seasonal beer sales grew about 23 percent in the first half of this year compared to the same period last year, he said.

“’What can I try that I haven’t tried before?’ is really driving a lot of the sales in the category,” Gatza said. “The craft beer drinker tends to like to have different beers in their fridges from different brewers on different occasions.”

Just as wine drinkers vary their selections by season and what they are eating, a growing number of beer drinkers want their beverage to work with what and when they eat.

“It’s a great marketing idea. You can call it a ploy, but it’s great to have the variety,” Russell says.

Wheat beers for summer, for example. “In the last two years, wheat beer has been the hottest trend in craft beer,” says Russell. “Everybody, it seems, is offering a wheat beer.”

Though fall and winter appear to have the most seasonal beer offerings, Russell says summer wheat beers “might be reaching, if not outstripping, seasonal beers as a style.”

For the breweries, it just makes good business sense. Besides giving consumers more choice in shops, at bars seasonal beers often land their own special taps. This is a move mastered by The Boston Beer Company, the maker of Samuel Adams.

Company founder Jim Koch has been a pioneer in the seasonal beer niche. But it hasn’t always been easy.

“For 15 years, consumers and retailers struggled with the idea” he says. “At this point, you’ve even got Bud, Miller and Coors jumping on the bandwagon.”

Koch first began making seasonal beers in the fall of 1987, when he offered a double bock followed by an Oktoberfest.

“In New England, we have very definite seasons, each of which has its own unique character and appeal,” Koch says. “I wanted to reflect the character of each season in a beer.”

“People feel the holidays as a special time of the year. They’re rooted in primitive instincts, that life changes when the seasons change,” Koch said. “We forget that we are natural beings in a physical world.”

Something to reflect on, perhaps, over a seasonal brew. So if you’re ready to add some seasonality to your beer drinking, here are some tips of what to look for:

Spring

The trees are budding. Birds are chirping. Life begins anew. Try Dogfish Head’s Aprihop, which is brewed with apricots. Or try a bock, a German beer originally brewed by monks for the spring. Strong and malty, bocks provided sustenance during Lenten fasts. Try Ayinger Maibock from Germany.

Summer

It’s hot, you’re thirsty and beer quenches like nothing else. Try a wheat beer, perhaps a Blue Moon, or Sam Adams’ Summer Ale. From Germany, seek out Franziskaner Hefe-Weissbier. From Belgium, try Hoegaarden’s Witbier, perhaps with an orange.

Fall

Harvest time. Oktoberfest for sure. But what better way to mark the season than with perhaps its signature flavor, pumpkin? Try Michigan Brewing’s Screamin’ Pumpkin Spiced Ale. Or Buffalo Bill’s Pumpkin Ale. Pumpkin: It’s not just for pie.

Winter

Get ready for serious choices. Anchor Steam’s Christmas Ale and Sierra Nevada Celebration Ale are good bets. From across the pond, Samuel Smith’s Winter Warmer is a stellar example.

From Belgium, try Corsendonk’s Christmas beer, one of Russell’s favorites. And if you can get it, Troeg’s the Mad Elf, Russell’s favorite Christmas beer, a potent offering brewed with cherries and balanced with spicy yeast.

On The Net:

Brewers Association’s searchable seasonal beer site: http://www.beertown.org/seasonal/index.html

Joe Sixpack: http://www.joesixpack.net

Sam Adams: http://www.samueladams.com