I spent the whole day thinking about this barley and carbon thing. Mainly because I am bad at science but it didn't distract me from the challenge. It just seems weird to me that someone can say that "the growing and processing of hops and malt into beer and whisky producing 1.5 per cent of Britain's greenhouse gases" while another beer study seems to show that the net benefit of barley to the planet is not included in the greenhouse calculation. How can that be? I usually don't fight these things. I usually line up, close my eyes and accept these things with an... err... open mind but you read stuff like this and it gets you thinking:
Over a 20-year lifecycle, the right species in the right conditions can absorb over 40,000 tonnes of CO2 per square kilometer. So a plantation of 100 square kilometers can absorb 4 million tonnes of CO2 over 20 years.
Which means that 100 square km can absorb 200,000 tonnes in a year. Or 2,000 tonnes per square km per year. Or, given that there are 247.1 acres in a square km, 8.1 tonnes per acre a year. Then there is the retention rate. If you look at footnote 24 (warning .pdf) , you'll see that the equilibrium level of carbon in cropland soils ranges from a minimum of 17 tons per acre to a maximum of 36 tons per acre (the mean is 24 tons per acre). A mature forest, by comparison holds 140 tons per acre which makes sense if you think of the trunks and branches of trees as a carbon sink.
So, crops like barley retain about 17% of the carbon that a forest does. Do they absorb at the same ratio? I couldn't find that fact. So, I am going with the 17% ratio for now. Which means that barley may well absorb 17% of 8.1 tonnes per acre per year. Or 1.377 tonnes. That's a lot. And what does it have to stack up against? One acre of malt barley will make about 540 cases of beer and a 60-case pallet of beer produces more than one metric ton (a tonne) of greenhouse gases which means that an acre's worth of beer production generates about 9 tonnes of carbon. But of that brewing production only 8.1% is due to the barley or 12% for once the barley is malted. Or 1.08 tonnes per acre. Which looks like to me that barley absorbs more carbon (1.377 tonnes) than it takes to get it into the malted state (1.08 tonnes).
Point? You don't get beer from looking at a bag of malt. But the closer you do, the less and less beer looks like a drain on the environment than the 1.5% might indicate. Planting enough forest for a perfect carbon off-set looks interesting as that 8.1 tonnes a year carbon debt to an average of 240 tonnes carbon credit per acre of mature forest could give a brewery a little under 30 years of 540 cases or 25 barrels of annual production. Which means Sad Adams would have to plant 80,000 acres to off set 30 years of its 2,000,000... (sorry)... 1,999,999 barrel production. Or 2,666 acres a year. Or 10.78 square kilometres a year. Sounds like a lot. Until you consider the scale of tree planting in British Columbia.
I am sure that is all wrong. There must be an easier way to determine all this other than, you know, relying on me.