Pumpkin beers are one of the great treats of the season. Their amber color and pumpkin pie flavor perfectly bespeak the fall harvest.

Beers have been made with pumpkins in this country since colonial times. Back then, barley wasn't grown here and importing it from Europe was expensive. The early colonists had to look to other sources for fermentable sugars to make beer. One of those sources was pumpkin. Even George Washington is purported to have made a pumpkin beer.

Modern pumpkin beers came about in the mid-1980s when California brewpub owner and avid gardener Bill Owens needed a use for a massive gourd growing in his back yard. He baked the pumpkin, mashed it with his grains, added some spices and sold the resulting brew in his pub. It was an instant hit. What began as a gimmick has in the past few years become a popular trend, with fans clamoring to get these beers as soon as they hit store shelves.

While recipes vary from brewer to brewer, today's pumpkin beers are nearly all built on a flavorful base of rich caramel malt. The squash has a fairly neutral flavor, but a light vegetal sweetness is usually present in varying degrees. Most brewers turn to spices like cinnamon, nutmeg and allspice to complete the pumpkin pie in a bottle effect.

A brew worth noting

Weyerbacher Brewing Co. from Pennsylvania has a wonderful example in its Imperial Pumpkin Ale. At 8 percent alcohol, it is a big and full-flavored brew with complex layers of caramel, bread crust, cinnamon and squash. Background chocolaty flavors give it an extra bit of character. It's like a spicy loaf of pumpkin bread.

Most pumpkin beers on the market are ales. Milwaukee's Lakefront Brewery has bucked that trend with Pumpkin Lager. Cinnamon absolutely dominates the aroma, reminding me of Red Hots candy. I almost expected heat when I tasted it. The flavor, though, is all about caramel and pumpkin, with the spices taking a back seat. Hints of raisin add some interest. Light body and a crisp lager finish make this an utterly sessionable beer.

For something a little darker, try Small Batch Pumpkin Ale from Tommyknocker Brewing Co. This English-style brown ale turned pumpkin beer has the caramel and spice, but with added layers of toast and roast. It's a bit more bitter than most, which helps to balance the malty sweetness.

The only local production brewery making pumpkin ale is Flat Earth Brewing Co. Its Mummy Train really is pumpkin pie in a glass, right down to the flaky crust. Last year the brewery made a change in its spice mix, turning what had been an overly spiced beer into one that is beautifully balanced. Currently available only on draft, Flat Earth expects to offer Mummy Train in bottles later this month.

For another local option, head to the Town Hall Brewpub in Minneapolis on Oct. 17 for the release of its Petunia's Pumpkin Ale.