MediumRoastSteam I’m happy to go with your maths rather than my memory (which is what I was going on, never a good idea so thanks for fact checking).
Recalculation in AUD (pay off period remaims in the more common currency of time)
Previous rossted beans for 800g was $40 (prorated from $50 per kilo)
Green beans $17 per kilo yielding 800g.
Bullet $5,000
1x roast per week saving 40 - 17 = 33 per week or 1,716 per annum.
5,000 / 33 = 3 years pay off. Not the 18 months that I remembered but still not too shabby.
No allowance for power, run off solar.
To be fair, I’ve used about 1 in 50 roasts for burr seasoning so there should be a small allowance made for waste, especially firing the early part of the learning curve. Another fact that diminishes my ROI is the temptation to occasionally buy beans at $30 a kilo.
@MediumRoastSteam I appreciate you catching my mistake. You could keep yourself gainfully employed as a fact checker.