One cup of coffee, traced back through the people, machines and systems that made it, then through the physical events those depend on. The upper tiers use H.T. Odum's emergy accounting: the total solar energy used, directly and indirectly, to make something, in solar emjoules (sej). Emergy measures cost, not value.
Sunlight is where the method stops. The page continues past it in ordinary physical units.
Trace a different object and the cup, the chain, the farm and the economy would all change. The sunlight tier and everything below the break would stay the same, because every object on Earth depends on the same sun, the same stellar history, and the same initial conditions.
The tiers are not a sum. After the chain, each tier shows the scale of a system the cup draws on, and only a small fraction of it went into the cup.
Emergy counts what was used to produce something. It says nothing about whether the thing is useful or worth having. Odum sometimes treated emergy as a measure of value. That move is the most disputed part of his method, and this page does not make it.
Georges Bataille argued that a society is defined less by how it produces than by how it spends the surplus energy it cannot use productively, and he traced that surplus to the sun. The lower tiers show that the sun's output is itself drawn from older stores.
Above the break: emergy estimates (sej) following Odum's method. They are order-of-magnitude, depend on where system boundaries are drawn, and vary between published baselines. Rain transformity and the geobiosphere baseline follow Odum (1996) and Brown et al. (2016).
The chain is a composite. Transformities are from Nicaragua, the price split is a 2019 UK breakdown of a café cup applied to a $3 cup, and services are converted at the 2011 U.S. emergy-to-money ratio. The bean's energy content (20 MJ/kg) and the beans per cup (≈ 15 g roasted, ≈ 18 g green) are assumptions. The farmer's share of about 1¢ comes from the same UK breakdown. Freight energy is derived from the UK government's average container-ship factor of 0.016 kg CO₂e per tonne-km. Brewing is not broken out; one study puts the whole chain at about 1.9 MJ for a 100 mL cup, most of it outside the steps shown.
Below the break: physical energies (J), order-of-magnitude. The Penrose figure is an estimate of initial-condition improbability, and its interpretation is contested.
Bars are log₁₀. Each section has its own axis, printed under every bar: sej above the break, J below it, W/m³ in the power-density panel, and years in the age panel. The chain uses linear shares. A bar is comparable only to bars on the same axis. Solid bars are amounts; bars with ticks are rates per year.
Sources: Cuadra and Rydberg (2006), emergy of coffee in Nicaragua · Campbell, Lu and Walker (2014), U.S. emergy and money flows · UK café cup cost breakdown (2019) · value distribution in German retail coffee · green coffee production energy, 10.7 MJ/kg · industrial roasting, 1.67 GJ per tonne, and the 1.9 MJ chain total · container-ship emission factor.
H.T. Odum, Environment, Power, and Society (1971) and Environmental Accounting (1996). Georges Bataille, La Part maudite (1949). Roger Penrose, The Emperor's New Mind (1989).