by bruceb » Tue Aug 29, 2006 8:22 am
Hello Guest,
Are the beans really oily or do they just look shiny? Do your fingers get oily when you touch them? Are the beans themselves very dark, almost charred looking? Oiliness in itself is not necessarily a defect. Are these from a small roaster or are they a brand name product?
In any case, the oil in itself is not the cause of the bitterness nor is it a necessarily a trait of a particular bean. As Davec said, the oil is driven out of the bean by high heat and/or long roasting, ie. a dark roast. However, the darker the roast the more bitterness appears. Just like burnt foods (sugar for instance) become bitter, coffee beans become more bitter when they are roasted very darkly. So the oil may not be the cause of the bitterness, but it does indicate a darker roast, which may be more bitter.
You have not told us how you are using the beans. They sound like a typical Italian "espresso" dark roast. Are you using them to make espresso? If you are, you may need to look into grinding, water temperature, pressure, extraction times, etc. Some coffees are more sensitive to extraction anomalies.
If you are doing something else with them such as making filter coffee or using them in a French press they may just not be suitable and you will either need to drink them yourself, give them away, sell or bin them.
One characteristic of oily beans is that they go rancid more quickly than non-oily beans.
I'm not familiar with the UK market, but certain chain espresso outlets are infamous for their "burnt beans," and French coffees are notably dark and most people find them bitter. I do know, however, that there are excellent sources of good, fresh-roasted beans in the UK.
Perhaps you need to tell us a bit more about the color of these beans and how you are using them.
Good luck.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters. I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!