Craft beer is a glorious thing. In 2013, over 15 million barrels (that's over $14 billion worth) of craft beer were sold in the US, and new breweries are popping up all over the place. And there are a plethora of choices, with an almost endless array of flavors (as evidence, last weekend I had a habanero pepper-infused brew from a new local brewery).

When you get past all of the adjuncts though, the brewing of beer has 4 main ingredients: water, malted barley, hops and yeast. Yet it's not enough to just add those things together in some proportion and hope beer comes out in the end. To that list of ingredients, add fire and the brewers art and you get the traditional Brauerster (brewer's star). It's the fire I want to talk about today.

The fire in brewing is used in "the boil." Boiling the water accomplishes two things, not least of which is sterilizing it so that the yeast you add later has the run of the place. But the hot water is also important for extracting nutrients like sugars from the malted barley and oils from hops. As you might imagine, generating the heat for boiling that 15 million barrels requires a boatload of energy, and while many brewers have turned to innovative strategies to conserve heat (such as heating the next batch with heat lost from cooling the previous one) or generating heat (such as using spent grain from the brewing process as fuel). But there's no getting around the need for other sources of energy, and new craft breweries are turning to sustainable ways of generating the fire required for their beer.

I had the pleasure of visiting the (still under construction) brewing operations of a new startup nestled in the southern green mountains of Vermont, that is running a kickstarter campaign to "get beer off oil," by converting a gas burner to use sustainably harvested wood pellets to generate heat.

Avery Schwenk, Vice President and Brewer (and full disclosure: college friend of my fiancée), met me in their new space in Brattleboro to tell me about their plans and let me taste some of their beer. He and his partner Christophe Gagné are passionate about sustainability, and also happen to make some really tasty alcoholic beverages. Based on the selection Avery poured, Hermit Thrush is bucking the trend of many small-scale craft beers that hit you over the head with intense hops or other strong flavors. Instead, the flavors are subtle, delicate and well balanced.

We tried a 3-year Kriek - a Belgian style beer that mixes batchs over 3 years and is aged in oak barrels (recycled btw). I generally don't like this style, because they're usually excessively sweet or sour, but this beer had just hints of sweet and sour, and a touch of cherry flavor blended with well with the hop and malt flavors. My favorite was the Belgian Bruin, a dark nut brown ale that was rich and creamy, yet somehow also crisp and light. I normally wouldn't go for a dark beer in the middle of summer, but it was somehow refreshing.

The quality of the flavors is no doubt a result of Christophe's passion for brewing. I didn't get a chance to meet him, but Avery tells me that he's spent years tinkering, and traveling the world collecting yeasts and trying different flavors. The microbiological interest of this pair is another thing I'm excited about, but that will have to wait for another post (for instance, I didn't realize that using bacteria in brewing is a thing...).

But for now, help them get beer off oil, and help them get their wood-pellet burner off the ground. They've only got 9 days left on the campaign and could use a boost.

For a full list of beers I tried and a slideshow of all the shots I took, click here.