We should start by saying that the ecological impact of breweries differ significantly from operation to operation, and the single most environmentally damaging part of the process is getting the beer from the brewery to our refrigerators. Logistics and distribution are challenges shared by many industries, so this being the case we’re going to focus on the brewing process itself.
At its core, beer is a simple agricultural product consisting of water, barley, hops, and yeast. All these ingredients have a long shelf life, so brewers can take their time sourcing them and ship them great distances if necessary. Brewers often go out of their way to get the highest quality ingredients, and can take the time to choose responsibly grown crops. But finding locally produced ingredients is a challenge for every brewery, regardless of size. Hops grow best in the climates of Oregon and Washington, and are known to be temperamental in other regions. And although barley is grown in many parts of the US, there are only a few malt houses large enough to fill normal orders (fun fact: barley must be roasted, a process called malting, to convert starches to sugars before it can be used for brewing). Some breweries even go so far as to truck in water if their local sources are high in minerals, which affect the flavor. As a side-note, this is why the craft brewing movement began in regions like the Pacific Northwest and the Rocky Mountains where water is plentiful, cheap, and clean.
So there’s clearly some impact in getting the ingredients from where they’re grown to where they’ll be used, and then there’s the challenge of figuring out what to do with the byproducts. In 1899 Budweiser became the first brewery to send its used grains to farmers as feed (sorry cows, there’s no alcohol at this stage). Since then it’s become common practice to use spent grain as feed, but some breweries are taking waste management to a new level. New Belgium Brewing Company diverts an impressive 99.8% of its waste from the landfill using a mix of recycling, compost, and even methane gas conversion- the brewery gets 15% of its energy needs from methane harvested from wastewater.
As with most industries, the sustainability of the product comes down to the individual company. With over 2,100 craft breweries in the US, the Brewers Association estimates that the average American lives within 10 miles of a brewery. Even if a craft brewery isn’t using local hops or barley, buying its beers means you’re supporting your local economy instead of sending greenhouse gasses up by having your drinks trucked across the country. So look for something local, and enjoy.