I drink coffee every morning, usually a couple of double espressos made using my Rocket machine. But the price of coffee beans has been creeping up and I've been trying to decide whether buying 'green' (unroasted) beans in bulk and roasting them myself might make financial sense. So whilst having a nice soak in a bubble bath this afternoon I tried running the maths in my head.
Two+ doubles per day = 750 cups per year.
Each cup uses about 20g of beans, so I'm using roughly 15kg of roasted beans per year.
I currently pay £5.40 per kilo of my usual† coffee, so £231 per year (or 31p per cup). Buying green would be about £11 per kilo for a 10kg bag. Losing maybe 5% on roasting would make that £11.55 per kilo, a saving of £3.85 per kilo, ignoring the cost of roasting.
I've roasted my own in the past using a converted popcorn maker but it only does 100g at a time. I'd need a larger roaster really. The Sandbox R1‡ would be great, but it's around £700 including the cooler. That's equivalent to 182 kilos roasted, or a smidgen over twelve years of morning espressos.
Sadly, this isn't going to be viable, is it :-(