The commodity game in coffee is a dodgy one... Folks buying commodity grade coffee really are buying "average grade" coffees at the price determined by the commodity market (NYCE for Arabicas and London Commodity Exchange for Robustas). This price swings violently based on time of year, weather, speculation and, of course, supply and demand. The thing that has the least impact on the commodity price of coffee is the quality of coffee.
This is why paying a premium for better quality coffee is just good business.
When buying coffee we buy two pieces, the commodity lot or future which defines the base price per pound of the coffee. One future/lot of coffee amounts to the current commodity price of coffee for a 37,500lb container/lot of coffee. So if I were going out to buy a lot of coffee on today's market I'd be first buying one future/lot of coffee at about $2.20USD/lb for 37,500lbs of coffee. That gets me my ticket to the dance. The next piece I have to buy/negotiate is the differential. The differential is the premium or discount applied to the coffee on a per pound basis. The differential is determined by overall coffee quality, availability, certification (sustainable or organic), demand and the volume of my purchase. The differential is negotiated between vendor and purchaser on a lot by lot basis.
In my 18 years in the coffee market I've seen the commodity price for coffee as low as $0.47/lb and as high as $3/lb. That price for the equivalent quality of the coffee you can buy in a big red, or blue, can. As those commodity prices go higher those manufacturers look for lower quality coffees to reduce their input costs. Likewise, as commodity prices go lower, producers of specialty grade coffees increase the differentials they demand for their coffees.
Sustainable certification plays a huge role in pricing, but at the end of the day can mean that the producer is reaping a greater financial reward, and is returning $$ in the form of increased labour costs to their workforce, and sustainable infrastructure on or near the farm.
-- Pat