Just as the depletion of chlorophyll exposes anthocyanin and carotenoid pigments in leaves, giving them brilliant hues of yellow, orange and red, the human body undergoes its own processes when the seasons change from summer to fall.

One such change includes our taste, or why we suddenly find ourselves eating foods or drinking drinks that we haven't indulged in all summer.

The Thermic Effect of Food, or TEF, offers one explanation. This relates to the amount of energy expended by processing food for use and storage during cooler weather.

"When it is cold, our body temperature drops and triggers us to reach for things that warm us up," said Katie Mazzia, a nutritionist at Vail Valley Medical Center. "Mostly, we start craving starchy, carbohydrate-rich things."

Availability is also an explanation. Since summary fruits and vegetables are no longer freshly available and may start coming with higher supermarket price tags come fall, shoppers instead reach for those darker, nutrient-dense foods that are easily accessible and less expensive.

Another factor that affects our changing fall appetite is the effect the shorter days have on our mood. When someone feels down, he or she might lean toward "feel good" food, such as dark chocolate; savory spices like clove, star anise, sage and rosemary; and dark berries and nuts. These foods are dense with polyphenols, micronutrients that have been shown to increase lowered serotonin levels in the brain, offering a sense of comfort.

All these things — calorie intake versus energy consumption, cravings for carbohydrates, availability and even attempts to comfort ourselves — have an impact on the types of food and drink we reach for in fall. Which explains why, come fall, we gravitate toward hop-forward ales and darker beers.

Ales and dark beers have between 42 milligrams and 52 milligrams of polyphenols per 100 milliliters of beer. A lager or lighter beer contains, on average, 28 milligrams per 100 milliliters of beer, according to Phenol-Explorer, an online comprehensive database on polyphenol contents in food and drink.

It's not surprising that with cooler temperatures, the fall hop harvest and shorter days, brewers look to oblige your subconscious with a new menu of beers.

Bonfire Brewing

Location: 127 W. Second St., Eagle.

Head brewer: Adam Bailey.

Fall beer releases:

• Woodsplitter is a Czech pale lager with 4.5 percent alcohol by volume, or ABV.

• Gyptoberfest is a Marzen/Oktoberfest style beer with 5.6 percent ABV.

Bonfire essentially turns its tasting room upside down come fall, with contributions from Bailey and his team of two other brewers. This year, they'll bring back Woodsplitter, a Czech pale lager to coincide with the Man of the Cliff festival in Avon. They'll also release Gyptoberfest in mid-September, their signature Marzen/Oktoberfest-style fall beer.

"It is a nice, malty beer, perfect for when everything starts cooling down," Bailey said of Gyptoberfest. "It has a big malt backbone and not as much hop presence. It is really satisfying. It makes you feel like fall."

Closer to the start of ski season, Bonfire will release another beer, its Fixed Grip saison, whose name is and ode to the days of fixed-grip chairlifts that didn't slow down for loading and unloading.

Bailey also plans to do some experimenting in the taproom come fall. They'll be brewing a harvest ale with hops grown in the tasting room in a small batch. Also, they plan to let loose with a pepper-cream ale brewed with habanero peppers.

"There are three of us brewing, and we couldn't be more different," Bailey said. "I am a traditional guy who likes a balanced beer that you can have a number of, not the sort of beer that crushes your palate. One of the other brewers is huge into German-style beers. The other guy loves huge flavors and brewing with chocolate and peppers and things like that. We say we drink what we brew, so there will be a lot of variety."

Brewery pick for epic leaf peeping: "I think Village to Village is pretty awesome. Riding the trail through the trees up there on a mountain bike is what I love to do to see the fall colors," Bailey said.

Leaf peeping details: Village to Village is a trail that connects Beaver Creek to Bachelor Gulch and then to Arrowhead. The trail bobs into deep forest near residential areas of Beaver Creek and weaves right back into the open, giving up huge vistas of the valley. One epic point on this trail comes back in the gully behind Arrowhead's residential area. There, a large plot of aspens intersects the pine forest, allowing for a striking contrast of pine green and aspen gold.

Vail Brewing Co.

Location: 41290 U.S. Highway 6, Units B-2 and B-3, Eagle-Vail, and 141 E. Meadow Drive, Unit 209, Vail Village.

Head brewer: Garrett Scahill.

Fall beer releases:

• CO-HOP Harvest IPA is a wet-hop style beer with an ABV near 7 percent.

• Gourde Range Pumpkin Spice Ale uses mulling spices. Scahill expects the ABV to be near 5 percent.

Vail Brewing Co. will have two beer releases this fall, one of which, the CO-HOP Harvest IPA, was sourced straight from the Eagle-Vail Community Garden. The brewery will only be doing one batch of this locally sourced beer.

"We get the hops right off the vine from the community garden, drive them straight over to our brewery (the Eagle-Vail location) and throw them into the kettle," Scahill said. "It is hop-forward, a wet-hop that tastes fresh, floral, citrusy and piney."

Scahill will also brew the Gourde Range Pumpkin Spice Ale, which will be released in mid-September, most likely.

"We use pumpkin in the boil," Scahill said. "Then we add a blend of spices from Breckenridge Spice Co. It is a Marzen/Oktoberfest-style ale with hints of pumpkin and spices such as cinnamon and other mulling spices."

Brewery pick for epic leaf peeping: "I'd say Kebler Pass. I think I read somewhere that Kebler has the largest aspen grove in the United States," Scahill said.

Leaf peeping details: Scahill spilled on a few more details about his route to Kebler Pass. He likes to take a long loop in the fall that goes right from the brewery's Eagle-Vail location over Battle Mountain Pass and Tennessee Pass toward Leadville and into Buena Vista. From there, he heads over Cottonwood Pass to Crested Butte and then over Kebler Pass into Paonia. Then he winds back through Carbondale and Glenwood Springs, onto Interstate 70 and back into Eagle-Vail. Oh, and Scahill may be right. While many say that Pando Grove in Utah is the largest aspen grove in the United States, many scientists believe a grove on Kebler Pass may, indeed, be larger; however, it hasn't been studied in full just yet.

Gore Range Brewery

Location: 105 Edwards Village Blvd., Edwards.

Head brewer: Jeff Atencio.

Fall beer release:

• GRB Oktoberfest is a Marzen-style ale that Attencio expects will come in at around 5 percent ABV.

This year, Attencio will create the GRB Oktoberfest. It is a German, Marzen-style ale with a few twists to make it truly unique.

"An abundance of Pilsner malt is accented with Vienna, Melanoiden and Caramel malts, and just enough Crystal hops to balance out the sweetness," relayed Pascal Courdouy, owner and head chef of Gore Range Brewery on behalf of Attencio. "With a full body and rich, toasty flavors, each copper-hued pint is the ideal brew to savor during our Rocky Mountain early fall season."

While Oktoberfest is celebrated during September, Gore Range will keep this beer on top throughout October.

Brewery pick for epic leaf peeping: "Our head brewer, Jeff Atencio, of 3 Freaks Brewery in Highlands Ranch, lived in Happy Valley for 15 years as a Vail Firefighter and has always considered Golden Peak his favorite place to see fall colors," Courdouy said.

"It probably has something to do with the fact that his marriage to Suzanne took place at the Vail Golf Course in late September of 1995. According to him, there's no prettier view in the state."

Leaf peeping details: Contrary to the gold medals won by Lindsey Vonn and Mikaela Shiffrin who use Golden Peak as a training grounds in the winter, this area actually earns its name from only a few weeks in fall. Located at the eastern-most lift on the front side of Vail Mountain, the top of the peak is one large aspen grove. As the leaves change, the area becomes vibrant in varying colors until a powerful gold color engulfs the peak.

Crazy Mountain Brewing Co.

Location: 439 Edwards Access Road, Unit B-102, Edwards, and 471 Kalamath St., Denver.

Head brewer: Ben Nadeau.

Fall beer release:

• Sticky Fingers Fresh Hope Ale is an American Pale Ale with 6.3 percent ABV.

Crazy Mountain Brewing Co. in Edwards will release its regular fall seasonal, the Sticky Fingers Fresh Hop Ale, which will utilize the special opportunity to brew with hops the same day they are harvested. The beer uses Cascade and Simcoe hops harvested from High Wire farms in Paonia to create a beer with a mellow bitterness that sets the stage for a grassy, earthy and citrusy palate.

Crazy Mountain will also release eight other beers in its Local's Stash Reserve Series. While the brewery has expanded its production to a larger brewhouse in Denver, it remains true to its mountain roots with this series of handcrafted beers brewed at the tasting room in Edwards.

These beers include a blood orange tripel, a rum barrel-aged dark ale with ginger and lime, a sauvignon blanc barrel-aged saison, an imperial Oktoberfest, a strawberry kiwi IPA, a strawberry milk stout, a dragon fruit smoked wheat and a s'mores porter.

Brewery pick for epic leaf peeing: "Probably booth falls," said Oliver Ristow, the tasting room manager at Crazy Mountain.

Leaf peeping details: People often forget to turn around when looking at the south side of the valley during the fall. Behind them, the sights can be equally spectacular. The north side of the valley near East Vail is home to the Booth Falls Trail. While known for its pumping waterfall in the spring and summer, the area surrounding Booth Falls is rich in early-autumn colors. Since the area is at a higher elevation and stuffed into a valley that receives less daylight, expect the leaves to change earlier than most.

7 Hermits Brewing co.

Location: 1020 Capitol St., Eagle.

Head brewer: Matt Marple.

Fall beer release:

• Punkin-A is a pumpkin pale ale with 5.5 percent ABV.

7 Hermits Brewing Co. of Eagle will bring back its Punkin-A Pale Ale, which offers a unique spin on the fall-favorite taste of pumpkin. It will be released in about three weeks.

"We use pretty much all the traditional spices that go into a pumpkin pie," Marple said. "We will do the mash with a bunch of roasted pumpkin. It comes out with all the taste of Thanksgiving."

However, Marple doesn't brew the beer to be sweet. He uses pale ale as the base so the taste of the spices and pumpkin isn't overwhelming. You are instead left with a very drinkable fall beer.

Brewery pick for leaf peeping: "I like taking my four wheeler up on Hardscrabble," Marple said.

Leaf peeping details: Hardscrabble Mountain road is a downvalley dirt road rife with trails, aspen trees and views of the Sawatch and Gore ranges. As the groves of aspens turn, the view from the top of the road is one of rolling colors stretching far into the valley and splashing up to treeline on the surrounding peaks.