Monday, January 25, 2010

the carbon footprint of beer

After that last post about 10:10, a comment was left from Dunc who said

I'm a craft brewer, and at least 10% of my domestic electricity use is for brewing. I could eliminate that overnight, but if I'm still drinking beer, I'm pretty sure that would actually increase my overall emissions (the bulk of the emissions from commercial beers being located in transport, packaging, and the retail environment, all of which I completely eliminate by brewing at home).

My gut feeling is that he's right about the bulk of emissions not being from the beer itself, but surely I could find some concrete evidence out there.

The Carbon Trust said

The carbon footprint of off-trade beer, the majority of sales, is dominated by its packaging (which for standard size units represents at least 50% of product-related emissions), with the overall footprint of a traditional disposable glass bottled beer generally higher than that of aluminium cans and PET bottles.

Coincidentally, in reading up about 10:10 I came across this article about Suffolk brewers Adnam's.

I've heard of numerous green initiatives they've undertaken in recent years, and my impression is of a company actually trying to cut things rather than just do a little greenwash. (But then, giving you such impressions is the mark of successful greenwash...)

Anyway, this caught my eye.

Adnams has reduced the energy used to produce each barrel of beer from 51.4kWh in 2007 to 46.3kWh in 2008.

The inclusion of an exact figure article set me off on a little arithmetic.

If we take 51.4kWh per barrel as average for beer, and presume that's a normal 72 pint barrel, we're looking at 0.714kWh per pint.

The UK electricity supply emits 460g of carbon dioxide per kWh of electricity.

This makes 328g/pint. That's the same as driving the average car about 2km, or eating four bags of crisps.

I then found the dependable Ask Umbra had covered alcoholic beverages.

Sapporo has started labeling beer cans with carbon footprints; their estimate is that a 350ml can of Black Label beer emits 161g of carbon.

That's about 261g/pint.

Umbra points us to a 2007 study for wine that showed that, in America, transportation accounts for about half of wine's carbon footprint, and the manufacture of bottles a further quarter. It's put numbers on something I've said before, that there's no excuse for Europeans drinking non-European wine.

In 2008 the New Belgium Brewing Company had a serious study done of a six pack of their beer (6x12floz bottles). They found it was a whopping 3,188.8g. By my calculations, that's 889g/pint*.

Perhaps there's something amiss in their having such a huge impact. Then again, it feels more likely that it's due to it being an exhaustive full life-cycle study. Emissions from the company’s own operations and the disposal of its waste accounts for only 5.4 percent of their emissions. They found the biggest single element was pre-chilling beer in those stupid open fridges in shops, accounting for more than a quarter of the carbon.

There are solutions to this, and not just by the obvious move of buying local, unrefrigerated beer (or brewing your own like Dunc). In San Francisco there's Carrotmob, who touted round local stores and had everyone go to the one that would give the greatest amount of the profits to energy efficiency improvements to the store, a total win-win.

THEN THERE'S THE WATER

The really alarming figure in the Adnam's article was this

It takes 8 pints of water on average to make one pint of beer.

(Adnam's have got it down to less than half of that, by the way).

There's so much cleaning of vessels and pipes to be done. But where does this figure come from? Does it include 'virtual water', the stuff used to make the ingredients and containers?

It's something that first hit me four years ago with the Independent's front page that said

The real cost of a bag of salad: You pay 99p. Africa pays 50 litres of fresh water


In soft drinks, made from crops grown in hot and artificially irrigated conditions, the figure can be astronomical.

Coca-Cola's Chief Executive E Neville Isdell said in 2007

it now only takes 2.54 liters of water to make one liter of Coke, compared with 3.14 liters five years ago

However other sources say that

there is as much as 250 litres of water used once growing the sugar cane used in the drink is factored in.


For many places, water is a pressing issue and will become all the more so as population increases and climate change intensifies. Even in well-watered parts of the world, treatment and pumping are large users of energy, so 'embodied water' in a product is part of its embodied energy and carbon emissions.

= = = = = = =

* 3188.8g divided by 2040ml (12floz), multiplied by 568 (number of ml in a UK pint)

8 comments:

Paul said...

The Independent's water comment reminds me of a bit from the documovie, "Home"

http://www.youtube.com/watch?v=jqxENMKaeCU

abut 41 minutes in, it shows pictures of a dry ravine where the river Jordan used to be, and informs us that it's water has been exported to supermarket shelves all over the world. Not in plastic bottles, but in capsicums and oranges.

Dunc said...

It's put numbers on something I've said before, that there's no excuse for Europeans drinking non-European wine.

Not necessarily... Wine shipped from southern Europe by road results in higher marginal transport emissions than wine from South Africa, because the main SA vinyards have railheads which take the wine directly to the seaports. (At least, that's what the owner of Great Grog claimed at last year's Big Tent. I haven't followed it up, but it seems plausible.)

Water is the place where commercial breweries really beat home brewing. I haven't fully quantified my water use (and it varies quite a lot depending on the time of year) but I'd be surprised if I manage with less than 4 gallons per pint produced, on average. I could reduce that a lot by switching to using a counterflow chiller rather than an immersion chiller, but it's difficult to see how I could set that up in my tiny flat... Some of my coolant water gets reused, but not nearly as much as in a commercial brewery. (If you're brewing continuously, you can use your coolant to mash the next batch, handily recycling both water and heat very efficiently. But I still think my savings on transport, packaging, etc win out in the end.)

Your kWh/pint figures seem quite high to me, but then I'm not having to maintain an industrial facility, and I'm not using pumps or active refrigeration at any stage. I generally reckon on 10 kWh (direct) for a batch, which is typically about 5 gallons - so I'm only using about 0.25 kWh per pint (not fusing too much about losses to yeast and the dregs at the end of the barrel). And that's electricity from Good Energy, so I reckon on zero emissions there... ;)

merrick said...

Dunc,

Wine shipped from southern Europe by road results in higher marginal transport emissions than wine from South Africa, because the main SA vinyards have railheads which take the wine directly to the seaports.

Sounds plausible. That American report on wine found something similar, that in much of the north-eastern USA it's lower carbon to get wine shipped from France than stuff driven from California.

But to act on this we'd need to be sure our South African bottles were definitely the rail/ship stuff.

when there's such great western European stuff, in such variety of styles and price, no real need to go beyond Germany I reckon.

Your kWh/pint figures seem quite high to me

not only are you not refrigerating and pumping, but are you leaving stuff to brew at ambient temperatures? The industrial brewers will be using continual heating of the mash.

electricity from Good Energy, so I reckon on zero emissions there

That's a sticky one, and I'm starting to wrestle with it. Expect another 10:10 style in-the-scales musing blogpost soon!

Basically, if the likes of you and me weren't using that electricity, it would be being sold to the grid elsewhere. It's a buyer's market for green electricity, all of it gets bought. So, if we use more, are we effectively just adding to overall demand, and somewhere down the chain of knock-on effects there's increased production at the places that can up their output, ie coal power stations?

Are green tariffs actually anything more than putting your leccy money with people who'll spend the profits wisely?

Dunc said...

not only are you not refrigerating and pumping, but are you leaving stuff to brew at ambient temperatures? The industrial brewers will be using continual heating of the mash.

Bit of confusion there... Most commercial brewers will be using Heat Exchanged Recirculating Mashing Systems (HERMS), but the mash only lasts a few hours at most and is quite thermally efficient when you're doing large volumes (I just mash in an insulated bucket over 90 minutes and don't worry too much about maintaining a precise temperature). For fermentation they'll be actively cooling the fermenters to maintain a constant temperature in the face of the heat produced by the yeast's metabolic activity (which can be quite significant - I typically see 2 deg C over ambient in my 5 gallon fermenter, and a commercial fermenter has a much higher ratio of volume to surface area). At the moment, I don't cool my fermenter (it's cold enough in the flat as it is right now), but I do have a thermostatically controlled heating system to prevent it from getting too cold - but that's only an 8W heating belt that runs for maybe a couple of hours a day, tops. I'm going to be looking at some refrigeration for brewing during the summer though, if I can find a suitable fridge second-hand. Mind you, I said that last year...

Yeah, the question of how to judge the emissions of nominally "green" electricity is a tricky one... At least Good Energy retire 5% more ROCs per annum than they use though, and they do give very good deals to small generators. It's not ideal, but it's the best I can do right now...

None of these questions are easy.

merrick said...

The effectiveness of retiring ROCs is the thing I'm starting to wonder about. Like i said, i think it'll be a full blogpost as I'd like it to snare comments from others.

Dunc said...

I look forward to reading it. I have to admit, I don't really understand how ROCs work.

lucy said...

hi - i'm just doing some research into carbon footprints of beer. i tried to find where your quote from the carbon trust comes from but can't find it with a google search. do you remember the name of the document / article?
thanks,
Lucy

merrick said...

Hi Lucy,

this is a long time ago, forgive my dusty memory, but I can't remember what the report was. The link goes to a document called "CTC_740_business_rev v5.pdf" that doesn't seem to be there any more.

Have you tried asking the Carbon Trust directly about it?