This small-town brewery in central Massachusetts is the only place in the world that sells Tree House beer, elevating its appeal among craft beer aficionados to cult status and smashing success. The Tree House Brewing Co. says it has been doubling its production every year, brewing 1.5 million gallons of beer in 2018.

CHARLTON — It’s a weekday morning in the dead of winter, but a long line of eager beer lovers is already waiting for the rustic Tree House brewery to open. Soon after the customers are allowed inside, they reemerge wheeling hand trucks stacked with cases of the beer company’s latest concoctions: Super Sap, BBBrighttt w/ Citra, and Lights On.


But Tree House has also been struggling with an unfortunate byproduct of the beer-making process: dirty water. Lots of it. So much that the brewer agreed, amid questions from Charlton’s sewer board, to clean the water emerging from its plant.

Now, the beer maker is turning to a Watertown tech firm for help in living up to its all-natural aesthetic. Cambrian Innovation plans to treat Tree House’s waste water on site, using a microbial system that promises to clean up the outflows while generating gas to heat the brewery.

“One of the dirty secrets about the brewing industry is that it’s not the most environmentally friendly undertaking, by the nature of the beast,” said Nathan Lanier, Tree House Brewing’s cofounder and head brewer, who could easily be mistaken for one of his customers in jeans, a Patagonia sweat shirt, mussed hair, and a scruffy beard.

Tree House Brewing Company co-founder Nate Lanier posed for a photo next to the future site of a microbial treatment system for their wastewater next to the brewery. Matthew Healey for The Boston Globe

For Lanier, Cambrian Innovation’s waste-water treatment system is a way to show he’s serious about reckoning with the environmental challenges that plague many of the small communities where craft breweries have sprouted like barley in recent years.

Along with pumping out a lot of impure water, he noted, the fermentation process generates significant amounts of carbon emissions, which contribute to climate change.


That reality clashes with the farm-to-growler ethos of the craft beer movement. Tree House, in particular, has traded on an image of environmental sensibility as it draws customers to its idyllic property with marketing images that feature glasses of its beer amid flowers and autumn leaves. It keeps beehives, maintains trails connecting its property to an adjacent nature sanctuary, and says it will use only renewable power generated onsite within five years.

But Tree House, like other breweries, needs lots of water to keep the beers coming. While much of it goes into the beer filling cans and tap lines, a huge amount is used to rinse tanks and clean equipment. Then it goes down the drain, adding strain to the sewer system in Charlton, a town of 13,500.

Without careful management, breweries can cause a surprising amount of environmental trouble. On Lake Champlain in Vermont last summer, for instance, officials pointed to waste water from beer and food producers as a contributing factor in a string of beach closures after a series of storms.

Robin DeLand, cellerman with Tree House Brewing Company, hosed down the outside of a bright tank while cleaning it at the brewery in Charlton. Matthew Healey for The Boston Globe

Michael A. Smith, an engineer with the Peabody firm Weston&Sampson who has worked on several brewery waste-water projects — including Tree House’s — said brewery waste is much tougher than normal household sewage for municipal facilities to treat.

Sugar and alcohol, which are major components of beer, can be costly to remove. When left untreated, they can attract microbes that suck up the oxygen that other organisms need.


Smith said craft brewers have generally been more prudent than major commercial breweries with their water supplies, producing only twice as much waste water as beer, compared with seven times the amount of waste water as beer for some traditional brewers.

Still, craft brewers have proliferated so quickly that some host communities are just beginning to understand what it means, environmentally speaking, to have one in their midst. There were 129 craft breweries in Massachusetts in 2017, nearly triple the number that existed six years before, according to the Brewers Association, a trade group.

“The craft brewers seem kind of innocuous, because they’re small,” Smith said. “People are just finally wrapping their minds around it, figuring out what’s going on.”

Tree House Brewing Company retail associate Delaney Parke filled an order for a customer at the brewery in Charlton. Matthew Healey for The Boston Globe

Tree House, founded in 2011, has already outgrown locations in two other communities, Brimfield and Monson. When it moved to Charlton, it immediately became one of the largest users of the municipal waste-water system.

Shortly after it opened there in 2017, a report by a town consultant raised concerns about the waste in water leaving the plant. By that November, the company had signed a deal with the community, agreeing to pay for every pound of certain pollutants it sent to the town, and to install equipment to pretreat waste onsite.

Lanier turned to Cambrian, which has built systems for several well-known beer makers, including Lagunitas Brewing Co., Bear Republic Brewing Co. , and Russian River Brewing Co.


Cambrian chief executive Matt Silver, who spun Cambrian out from MIT in 2007, said this is the first project in Massachusetts for the company, which has gotten support from several federal agencies, along with $800,000 in state grants to help commercialize its products.

He said projects like the Tree House system are helping to make the case that biological waste-water treatment can be done reliably and efficiently on a smaller scale than at centralized municipal plants that use similar techniques.

Lanier sees the Cambrian system as a wise investment — though neither company would disclose the terms of the deal.

Cans of Tree House Brewing Company's New England IPA Julius made their way down the canning line. Matthew Healey for The Boston Globe

The new waste-water system will resemble a set of shipping containers, whose industrial look may clash with the brewery’s cabin-in-the-woods aesthetic and heavy design emphasis on wood grain. But it fits, in its way: Once the system is up and running, Lanier says, the water at Tree House will be clean enough to reuse (though it will be used for cleaning, not brewing). The companies said it will also offset 21,000 metric tons of carbon emissions each year.

For Keith DellaPorta, a Billerica resident who drives an hour and a half every few weeks to visit the brewery and stock up, the sustainability is part of the appeal.

“I think he would give up profit to make the environment cleaner,” he said of Lanier, a well-known figure among his customers who regularly jumps into conversations on social media to ask what folks think of the beer.


“When you get there, the feeling is warm and comforting. It’s not a city feel, it’s away from the clutter,” added DellaPorta, who once waited in line over two days to get four cans of a special, limited-time beer called Juice Machine — and says he’d do it again.

For Lanier, there’s another reason to care about clean water. The municipal supply in Charlton, which comes from nearby Southbridge, is delicious, he said, and that plays a big role in the flavor of the beer.

“Clean water is something that I aspire to have, because it’s a finite resource,” he said. “So I feel a social responsibility to invest in a system that actually returns water to the earth in the condition that we took it.”

Andy Rosen can be reached at andrew.rosen@globe.com.