However much I might lament the inexorable downward trend of everything that was once bright and good about my country, I was born an Englisshman and am still one today — which means I drink a lot of tea. (That me be the one aspect of Englishness that survives the current apocalypse.)
I am drinking even more tea than usual at the moment, because I am once more trying to lose weight — to get below that obese threshold, into the merely overweight. Tea fills my belly without loading up the calories.
And it occurred to me to wonder how much each cup costs.
Let’s start with the tea itself. Our general-use tea is whatever is cheap from whatever supermarket we’re ordering online groceries from. Currently we’re favouring Asda, and I see that presently they’re selling ASDA Everyday 240 Tea Bags for £1.87. We tend to order about £150 of groceries at a time and pay something around £4 for delivery, so that’s about a 2.5% delivery charge, bringing the tea up to £1.92. That comes out at 0.8p per tea bag.
I put a dash of milk into each cup, but it’s hard to know exactly how much that is. Let’s assume about 15 ml. We buy four-pint bottles of ASDA Semi Skimmed Milk for £1.09, or £1.12 including 2.5% for delivery. Four pints is 2273 ml, so 15 ml is 1/152 of a bottle, costing about 0.7p.
Our water is metered at £1.43 per cubic meter. To boil the kettle, you need half a litre of water even if you use less than that, so let’s say it’s 1/4000 of a cubic meter, costing 0.04p.
Finally, we come to the electricity used to heat the water. To raise 0.5 litres of water from ambient temperature of about 16° to boiling point is equivalent to raising 1 litre of water by 42°. The specific heat of water is 4.19 kJ/kg°C, so we’re using 176 kJ. That’s 0.05 kWh, and our electricicy supplier charges about 16p per kWh, so it’s costing us 0.8p to heat the water. (Sanity-check: it’s a 2 kW kettle and it takes about two minutes, or 1/30 hour, to boil, so that’s 1/15 kWh, which is 0.07. Close enough to the 0.05 I calculated to give me confidence I didn’t skip an order of magnitude or something.)
So the total cost of a cup of tea is 0.8 + 0.7 + 0.04 + 0.8 = 2.34 pence.
I call that good value.
(Obviously when you spend £1.80 on a cup of tea at Starbucks, what you’re paying for is not the tea. The value to you is being in the locations, possibly with friends, or possibly as a convenient place to work on your laptop. The cost to them is rent, heating, lighting and staff. The tea, at 1.3% of the price, hardly even factors into it.)