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AskPablo: Bottles and Cans (just clap your hands)

| Monday September 25th, 2006 | 5 Comments

md_bkbh501012.jpgHello friends! This week we are talking about a subject that is very dear to my heart, beer (Hooray Beer!). This weekend I spoke to the students at Hunter Lovins’ “Principles of Sustainable Management” class at the Presidio School of Management about measuring sustainability as well as the Wuppertal Institute‘s “MIPS” Material Intensity Analysis method. I decided to create a hands-on example just to give them a taste of my favorite kind of headache… Since the results were interesting, and I’m too busy to do two MIPS analyses in one weekend, I am sharing it with you. Pop open a cold one (but only if it’s after five somewhere…) and enjoy!
Pablo’s Microbrew has a problem… They want to sell beer on the East Coast but need to select a container. Since they are a sustainable company they want to minimize their impact on the environment. Should they use aluminum cans or glass bottles?


For this analysis we need to make a few assumptions. I am giving you access to the Google Spreadsheet that I used for this analysis so feel free to recreate the analysis with your own assumptions. So, let’s say that we can choose between primary aluminum (virgin material) shipped from China (10,500km, by container ship), secondary (recycled domestic) aluminum (1000km, by semi), and domestic glass (1000km, by semi). The target market is located in New York and the brewery is in San Francisco (4,700km, by semi). The empty can weighs 15g and the bottle weighs 170g, both hold 12 oz. of beer (355g, the material intensity of which can be neglected since it is the same for all three). So, we need to calculate the material intensity of the beverage container production, empty shipping to the brewery, and full shipping from SF to NY. Again, I am using the MIPS data tables v2.0 from the Wuppertal Institute for the raw ingredient and transportation material intensity. The calculations are in the spreadsheet linked above, here are the results:
The abiotic input into both the primary aluminum and the glass is very close, 555g and 516g respectively. This includes the mining of Bauxite and Silica for each as well as any fossil fuels required. These values are per container, not per gram, so if both containers weighed the same the glass would have a much lower impact. The secondary aluminum is obviously the winner with only 13g, which is less than the weight of the can. The reason for this is that the aluminum has already been used and would otherwise be land-filled, therefore we don’t need to count the impact of the original aluminum production (BTW: see pp.49-50 or “Natural Capitalism” for a great overview of the journey of a can).
Due to the mining and refining of the aluminum its water use is the highest (16 liters per can) but the production of the glass bottle is also significant (3 liters per bottle). Most likely this accounts mainly for power-plant cooling-water used in the production of the electricity used to make the glass. With greenhouse gas emissions the primary aluminum sucks the most (163g), followed by the glass (122g).
Are we done? No. We need to consider the impact of transportation from container manufacturer to brewery (based on empty weight) and brewery to customer (based on filled weight). This is where glass’ weight disadvantage becomes crystal clear… With the impact of shipping and trucking included, the glass has an abiotic material intensity of 1.1kg and is responsible for 637g of greenhouse gas emissions. The primary aluminum is not too far behind though, with .94kg and 529g.
But, all of this is based on my assumptions. If you have a better idea of where each container is made just change the numbers in the spreadsheet. You can also change the numbers to see how much closer the glass bottle factory would have to be to justify using it. And just for fun, I threw in some comparisons at the bottom of the spreadsheet. You can also figure out your own, like “How many Olympic-sized swimming-pools of water are used to produce all of my brewery’s aluminum cans?” Have fun, I know I did!
* One little footnote. Several years ago in a plastics engineering class the Prof. told us of the “next generation beer bottle, made out of PET. This type of bottle, if drinkers would accept it, would weigh much less than the glass bottle and would have a much lower material intensity than the aluminum can. But until alcoholics everywhere get eco-savvy we are stuck with glass and aluminum. While aluminum is readily recycled glass has little value. It costs more to ship it somewhere than it does to make new glass from its main ingredient, sand. I know that glass from the San Luis Obispo recycling facility gets trucked to Bakersfield to sit on a pile and wait until its value goes up (at least this was the case a few years ago).
** OK, one more footnote… In Europe there is a standardized design for glass beer bottles and plastic soda bottles. They are a bit beefier but are collected and reused over 10x. Imagine, your Budweiser bottle (if you like that vile filth) enjoying a second life carrying some Anchor Steam (a fine beer, by my standards), and then another life carrying Boont Amber, and another life back to carrying Budweiser (piss-water)… This system works great when there are regional collection and distribution centers. In Germany there are breweries and beer drinkers everywhere. You can imagine in the US that such a system might be less efficient if bottles have to be returned over long distances to get to the large industrial breweries. Although it would probably still be more efficient than the current system (or lack thereof). So, what do we do? Give up drinking? Never. I practice distributed production… I make my own beer and bottle it in reusable Fischer Amber bottles (with the ceramic flip-lid) that I personally painstakingly had to empty of their liquidy goodness. You can find a homebrew kit and ingredients at your local homebrew store and Fischer bottles at your local grocery store.


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  • http://www.todbrilliant.com todbrilliant

    Oh, don’t forget to make sure the recycled aluminum content doesn’t get earmarked for liquifaction and spraying directly onto the ground in stripmine operations. Some years ago, we found out that’s EXACTLY what happened to the recycled cans in my wee town of Chico, California. My details are off (liquifaction, for example – it was mixed with something else and used as some sort of ‘acid’). No, the recycle game is far from clear. . .keep on digging and you’ll find lots of contaminated dirt!

  • http://www.triplepundit.com Nick Aster

    Pablo – but isn’t the footprint of a bauxite mine vastly larger than that of a silica source? Not just in terms of carbon, but in terms of other effluent and massive impact on the landscape?

  • Pablo

    Nick,
    I prefer not to use the term “footprint” since it is two dimensionsal and material intensity is three dimensional. Yes, Bauxite has a greater material intensity, and that is included in the material intensity factors provided by the Wuppertal Institute. The reason bottles and cans are somewhat close though, is because the bottles weigh a lot more.

  • http://www.todbrilliant.com todbrilliant

    I know the above scenario doesn’t make sense. Using aluminum cans to get bauxite. . .can’t find any reference either. Will keep digging.
    Another one that gets me: Disposable blades v. electric shave v. straight blades.

  • Arian Smith

    Brewing your own beer, soda and wine is certainly the way to go if you care about recycling. 2 liter bottles can be reused for the soda many many times. Beer bottles can be cleaned and reused as long as the glass seal remains intact (so treat your bottles well). Wine bottles will likely last even longer than beer bottles as they use a cork rather than a metal cap. Reuse first, then recycle.

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