I roast my own coffee and have some questions concerning brewing light roast coffee, like kenya/ethiopian roasted to city-city+. But when I dose this at 60 grams pr liter water, compared to other darker roasts, I have to either updose the amount of coffee or adjust my grinder to a finer grind. I seem to struggle with finding the right way to do this, often ending up with bitter (overextracted?) coffee. How do you compare light roasts with medium dark(full city - full city+) roasts when brewing either drip or french press, are there any rules of thump for this? For me light roasts seem to work best in the french press compared to the drip method.

Gismar wrote: ... when I dose this at 60 grams pr liter water, compared to other darker roasts, I have to either updose the amount of coffee or adjust my grinder to a finer grind.

Why do you have to do this?

I see two possibilities, and neither requires changing the way you brew

First, you may be unfamiliar with the taste and balance of light roasted coffees. These are about crisp acidity and light sugars, not heavy caramels and roasty distillates. Grinding finer will just get you a dull and bitter tasting over extracted mess; up-dosing will get you more acids and sugars; but neither will get you more roast flavors. Expect the coffee to taste a lot more tea or white wine like.

Second, you may be unfamiliar with how to roast light. If the coffee tastes grassy and vegetal, or like swimming pool chlorine, or overbearingly tannic, then you messed up the roast. If so, no brewing tricks will help, and no amount of habituation will make it taste better. Roasting light is much harder than roasting dark; so your first few dozen light roasts are quite likely to be poor. The best learning strategy is roast just slightly lighter at each step, while keeping the length of the roast from the start of the first crack to the end of the roast about the same length, no matter how light you roast (i.e. reduce the heat more drastically just ahead of the first crack for light roasts than for dark roasts). By keeping the roast timing the same, you will ensure the elimination of grassy and other raw flavors, and also achieve a familiar and tasty balance of sugars to acids.

I'd add that generally speaking the lighter the roast, the longer the rest needed for full flavor development.

another_jim wrote:First, you may be unfamiliar with the taste and balance of light roasted coffees. These are about crisp acidity and light sugars, not heavy caramels and roasty distillates. Grinding finer will just get you a dull and bitter tasting over extracted mess; up-dosing will get you more acids and sugars; but neither will get you more roast flavors. Expect the coffee to taste a lot more tea or white wine like.

Thats very good news actually, it is very tea-like. It is a sweet and fruity taste, which becomes much clearer when the cup has cooled for a while. I really enjoy this coffee myself, but was very unsure of how to get this coffee right. I have got a feeling that I have nailed the roast on this one now, although it probably is too light for alot of people. When I cup the coffee the fruitiness is very clear, but I was afraid I did something wrong when brewing it. The roast is a very fast one, with alot of heat all the way. Time from first crack til drop the roast was 3.05 min, the drop temp was 392 f. First crack started at 374 f.

Thanks jim for taking time to analyze my light roast brewing problems. I have read very much of what you have written one the homeroasting forum, its very generous of you to share your knowledge like you do.

Regards from Norway.

Yep, sounds like a real good light roast. Perhaps it's the wrong season for it; I tend to roast for caramels and spices this time of year (although the occasional clementine coffee is nice too)