Sustainability: A Focus on Brewing Efficiency
by John Nelson
A key component in becoming more sustainable, is becoming more efficient in all aspects of business operations. For breweries, addressing beer production efficiency in particular, is paramount in solving the sustainability puzzle. Which brings up some bad news…beer is not exactly an ‘efficient’ product to make.
From barley to bottle, beer has a long and windy production road consisting of malting, hop growing and processing, water treatment, the actual brewing process, packaging, distributing, (okay, you get the gist): There are numerous raw ingredients needed, vast amounts of energy required, and undeniable emissions released in order for you to be able to unwind and enjoy your favorite craft concoction.
Don’t feel guilty about drinking that delicious IPA though: Process efficiency-focused technologies are continuously improving and gaining momentum within the industry, allowing brewers to produce more, while using less. “Reduce, reuse, recycle” typically apply to solid waste reduction, but organizing the following industry focuses under those general umbrellas is helpful for envisioning specific sustainability benefits. With that, let’s look at a few areas brewers and engineers are focusing on to improve brewing efficiency.
Milling and Mashing:
The first step in the brewing process is milling, or ‘cracking open’ malted barley. Malt must first be milled in order to access the starches inside. Dusty, freshly milled malt (now called ‘grist,’ pictured in the photo below) is combined with hot water in the next step of the process (called ‘mashing’) to convert the starch to sugar.
The degree to which the malt is milled has an enormous influence on how efficient the mashing process is. Finer grists (flour) provide more sugary extract, and coarser grists (chunks of grain) provide less. Most breweries use a ‘mash tun’ for the mashing process. A mash tun is essentially a large strainer that retains grain material, but allows sugary water (now called wort) to be flow into the next step; the boil.
Mash tuns can be rather inefficient though. Because they use strainer-like screens, they cannot handle finely ground grist, as this clogs the screens, resulting in a ‘stuck mash’ and an angry brewer. Often having no choice, brewers resort to using coarser grists, which inevitably result in less sugary extract.
The ‘mash filter press or MFP’ (pictured in the photo below), on the other hand is capable of handling flour-like grists. With these systems, the mash (grain and water) is pumped into individual chambers, and then ‘squeezed’ (using compressed air); the concentrated sugary wort exits, and the compressed grain stays behind. Think of it like a French press for your morning coffee.
This MFP squeezing often results in 98+% mash efficiencies, which is extremely significant compared to a typical mash tun, which can range anywhere from 70-92%. Though they’re not brewers ‘main squeeze’ yet (bad brewer pun), MFPs are gaining steam among craft breweries due to their increased efficiencies.
As mentioned, boiling follows the mashing step. Brewers boil wort to increase flavor (like the wonderful hop compounds we know and love), increase color and clarity, and to sanitize the wort. An additional benefit to boiling is that off-flavors (ones that taste like cooked corn or cabbage) are evaporated, allowing for a cleaner tasting beer. Yuck…cabbage pale ale? No thanks, crank up the heat!
But boiling large volumes of wort for an hour can take considerable amounts of energy. One way to make the process more efficient is through forced convective heating. House furnaces provide a great example of forced convection: Your furnace creates heated air, and then forces the air through different air ducts to more efficiently heat your house. If the heated air rose naturally instead, the process would be considerably less efficient.
Newer boil kettles utilize similar principals: Boiling wort is drawn near the bottom of the kettle, and is recirculated back through the top with an external pump (the photo below shows wort returning back to the top of the kettle). This constant boiling movement allows for increased evaporation rates, shorter boiling times, and considerably less energy needed.
Throughout the brewing process energy is often wasted in the form of heat or cold. By capturing this wasted energy, breweries can then transfer it to a part of the process where it can be utilized. Boiling is a perfect example: Some breweries capture the hot vapor evaporating from the boil kettle, and then use it to warm up, or pre-heat the next batch of wort before it gets to the boil kettle.
Breweries are increasingly devoting attention to utilizing CO₂ naturally produced as a byproduct of beer fermentation. The system below, used by Sierra Nevada Brewing Company, captures CO₂ in a balloon, and cleans it from off-aromas. The CO₂ can then be used for different steps in the cellaring process (carbonating, packaging, etc.). Watching a gigantic balloon fill up with gas must be extremely satisfying, especially knowing the gas is receiving a second life.
While we’re on the topic of balloons, below is a glimpse into New Belgium Brewing Company’s wastewater system. Brewery wastewater can be highly problematic for local wastewater centers to process. New Belgium not only ferments wort into beer, but they also ferment wastewater as a means of ‘pre-cleaning’ it before it is sent to the treatment center. A byproduct of wastewater fermentation is methane, which fills the balloons, and can then be burned to supply energy to the brewery.
Algal CO₂ Scrubbing:
Though this innovation loosely relates to process efficiency, it was too cool not to mention. Brewers at Young Henry’s Brewing Company in Australia are collaborating with the University of Technology Sydney to better understand algae’s potential at ‘scrubbing’ CO₂ emitted during the fermentation process.
Algae metabolize CO₂, use it to grow, and subsequently release oxygen as a byproduct. Algae is being increasingly studied as a replacement to fossil fuels. This particular project is still very much in the research phase, but the potential it brings to emission reduction across the industry is extremely exciting.
Brewing in a remote location like Juneau, Alaska presents many logistical challenges. Alaskan Brewing Company addresses such challenges by increasing process efficiency: Alaskan was early to implement a mash filter press and a CO₂ recovery system, but their newer fuel-alternative system especially stands out among sustainable craft technology.
Spent grain is the leftover byproduct after the mashing step. After brewers extract starch from the grain and convert it into sugars, they no longer have a use for it; hence dubbing it ‘spent’. This grain waste still contains considerable protein and fiber content though. Because of the health benefits associated with spent grain, it often gets used as a ‘filler’ for animal feed (typically cows), and even finds its way into human food, where anything from spent grain pizza crusts to bread loaves are becoming more and more common…yum!
But being the 22nd largest craft brewery in the country, Alaskan has a lot of spent grain, and noticeable problem specific to Juneau; “no cows!” Because of this, Alaskan had to ship dried grain to the lower 48 to be used as cattle feed. In 2012 though, the brewery implemented their state of the art ‘Spent Grain Steam Boiler,’ which allows them to burn the grain material and use it as a fuel for their brewing system. “With the new system, which became operational at the end of 2012, we have a goal of reducing our overall oil use by more than 65 percent” (Alaskan Brewing).
Many process improvements addressed above come with steep initial price tags, hence them more commonly being implemented by well-funded, medium- to large-sized craft breweries. Let’s not forget the little brewers too though, as they make up the majority of the nation’s craft breweries. Consumers and brewers alike should cheer on process efficiency improvements for small scale systems as well.
Just as it will take well-designed technologies to fight the impacts of climate change, the brewing industry will need the same to move closer toward carbon neutrality. The craft brewing industry is already a story of economic success. Through better process efficiency, it can be an industry of sustainability success too.
Mash Filter Press and Boiling:
- Brewing and Malting Technology 5th Edition by Wolfgang Kunze
Alaskan Brewing Beer Powered Beer:
Spent Grain Nutritional Assessment:
Mash Filter Press:
Sierra Nevada CO₂ Recovery:
New Belgium Wastewater Digester:
Algae CO₂ Scrubbing:
Alaskan “Beer Powered Beer”:
Alaskan Spent Grain Boiler: