More sustainable pick-me-up: can of coke or cup of tea/coffee?

Question

Question: which has a greater embodied energy: a cup of tea/coffee or a can of Coke (or Pepsi, or other caffeinated soft drink) -- or maybe some other stimulating drink? I have made some estimates of my own, but there are some areas I haven't been able to figure out e.g. transportation, and I am looking for someone who may be better informed.

Factors

Cup of tea/coffee:

1. Production of packaging
2. Transportation from country of origin
3. Heating water

Can of Coke:

1. Production of packaging
2. Transportation of raw ingredients
3. Manufacture
4. Transportation of product from the factory

My estimates:

Boiling one cup of tea: 0.11 kWh

500 g water (minimum amount for typical kettles)
Q = mcΔT
Q = Heating required
m = Mass of water = 0.5 kg
c = Specific heat capacity of water = 4.18 kJ/kgK [1]
ΔT = 85 Kelvin
Q = 178 kJ = 49.4 Wh
Efficiency of electrical power grid (e.g. in the US) [2]:
Generation: 40%
Transmission: 94%
Net effy = 38%

So total energy cost of a cuppa I'd reckon is 413 kJ = 0.110 kWh

Aluminum can production: 0.28 kWh

14.9 g : Mass of an empty can [3] 
183e9 kWh : US total Aluminium industry energy consumption (2003) [4]
9.6e6 tonnes : US Aluminium industry raw materials used (2003) [4]

This gives 19.1 kWh/kg, or 0.28 kWh/can

Manufacture: ?

Not sure about energy required in manufacturing coke or blending tea.

Transportation: ?

Suspect transportation is fairly negligible in both cases as neither are perishable so probably transported by sea and road, which is relatively efficient.

References

1. “Water - Thermophysical Properties.” [Online]. Available: https://www.engineeringtoolbox.com/water-thermal-properties-d_162.html. [Accessed: 23-Jan-2018].
2. “Energy Efficiency in the Power Grid - NEMA,” mafiadoc.com. [Online]. Available: https://mafiadoc.com/energy-efficiency-in-the-power-grid-nema_59842ba91723ddcf69a39c32.html. [Accessed: 23-Jan-2018].
3. “How much does an empty soda can weigh?,” Reference. [Online]. Available: https://www.reference.com/food/much-empty-soda-can-weigh-e7e0417d7a8ec29. [Accessed: 23-Jan-2018].
4. E. Efficiency, “US Energy Requirements for Aluminum Production,” 2007. Available: https://www.energy.gov/sites/prod/files/2013/11/f4/al_theoretical.pdf

Answer 1

TL;DR -- The best option, per liter, is tea. Soda is about twice as "bad," and coffee is two times worse than that.

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To compare the environmental impact of various beverages we need to perform a life-cycle assessment. From Wikipedia:

Life-cycle assessment (LCA, also known as life-cycle analysis, ecobalance, and cradle-to-grave analysis) is a technique to assess environmental impacts associated with all the stages of a product's life from raw material extraction through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling.

In 2010, Nestle Waters North America commissioned a study to look at the environmental impact of various beverage choices. They hired Quantis to do this study. According to their website, Quantis

[...] guide[s] top organizations to define, shape and implement intelligent environmental sustainability solutions [...] We are [...] sustainability’s scientists, experts, strategists, innovators and visionaries.

The study is titled "Environmental Life Cycle Assessment of Drinking Water Alternatives and Consumer Beverage Consumption in North America", and looked at 13 popular beverages in North America, including coffee, tea, and soda. The report includes new research as well as reviews of existing studies, and provides the following chart:

A table showing the values per liter (and references) is provided later in the report:

Unfortunately, this table shows the weighted average of hot tea and iced tea. From the chart though it's clear that hot tea has a much lower overall carbon footprint.

Conclusion: hot tea is the most sustainable pick-me-up. A can of coke is about twice as bad, and a cup of coffee is about four times worse.

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Corroboration

The previous version of this answer had a few different sources that corroborate the chart/table above, without the nice comparison:

• "Life cycle environmental impacts of carbonated soft-drinks". Carbonated beverage in an aluminum can: 312 gCO2eq/l. (Note that this study is specific for the UK.)
• Coca-Cola UK also commissioned the Carbon Trust to calculate the carbon footprint of a can of Coke. Their finding is actually a bit higher, at 515 gCO2eq/l.
• "Life Cycle Assessment of coffee consumption: comparison of single-serve coffee and bulk coffee brewing" (pdf): The range of values for coffee is 828 to 1395 gCO2eq/l.
• "Life cycle assessment of spray dried soluble coffee and comparison with alternatives (drip filter and capsule espresso)" (numbers available here): drip coffee: 1,140 gCO2eq/l.
• "Life cycle assessment of tea produced in Kenya": hot tea, depending on country of origin: 105 to 209 gCO2eq/l.

Answer 2

Sustainability isn’t just about energy. It also involves other pollutants and water usage.

Tea uses 100 times the volume you drink to be produced. [1]

And according to this [2] it takes 65 times the volume of water for one litre of Coke. But that doesn’t take into account the mining of the metal for the can, nor the transport of the Coke can (water for your tea is local), or the recycling required to melt the aluminium can again. Whereas tea is generally drunk from a reusable cup.

My guess is that the Coke is worse for the environment overall.

[1] https://www.huffingtonpost.com/2014/10/13/food-water-footprint_n_5952862.html

[2] https://www.quora.com/I-have-read-that-it-takes-9-liters-of-water-to-produce-1-liter-of-Coca-Cola-Is-it-true