I usually use light or medium roasts for making espresso with good results. Just out of curiosity I bought a pound of a darker-roast blend from my local roaster. The blend is mostly Sumatra, done to a Vienna or light French roast. A little bit of surface oil is visible. This is a blend used in the shop for drinks over 12oz. Sadly, every shot I make is coming out bitter. It was roasted last Wednesday - I got it 2 days post-roast.

I've tried going down to 14g at 196 degrees, but still a lot of bitterness - it's noticeably unpleasant even in a 6oz cappuccino.

I feel like there's some magic lurking in the Sumatra, if I can just find it. Giving up after just a few days feels like a cop-out (but I did buy a bag of my regular lighter-roast blend today, just in case).

Does anyone have any tips for getting good espresso out of dark roasted beans?

I tried a Sulawesi SO that was roasted similarly a couple of months ago. I never got a shot that I considered well-balanced out of it. The best shots from that batch were low dose, normal flow, cut early, low temperature. Like 40-45mL from a 15g dose in 20-22s at around 190°F. (I tend to like most of the coffee I more typically purchase somewhere in the vicinity of 197°-200°F, 17-19g, 50-60mL in 28-35s.) I've recently adopted the habit of weighing my shots, but I wasn't doing that when I had those beans

So maybe try dropping the temperature drastically, running normal flow at a low-ish dose for your equipment and cutting the shot early.

In the end, I decided to stop tormenting these particular beans with my espresso machine and enjoy them in my pour cone. They were much better that way.

There are very few roasters who have successfully roasted coffee to a dark level, that results/resulted in good straight shots of espresso. Alfred Peet, who founded the Peet's Coffee chain, is reputed to have done so, although I never had an espresso in one of his cafes when he was in charge, and the only straight shots I ever had there afterwards were not pleasing to my palate.

Supposedly, one needs to have the knack for selecting beans that can endure such a dark roast, and one also needs to know how to roast that darkly, if the shots are to be "appreciated" straight. If the shots are to be put into a giant milk drink, however, the negative "burnt tasting" aspects are certainly diminished.

As a general rule I would avoid buying darkly roasted beans or roasting them yourself to much beyond the onset of 2nd crack, if the purpose is to enjoy them for use in straight espresso shots.

ken

back when i was roasting for Broad Street Coffee Roasters, .. an old outfit from Durham NC now defunct, we did a great job on the darker roasts but we were using 100 year old Barth Roasters (the ball type) and they produced amazing coffee .. (you have to forgive my passion,i loved those roasters!) .... Dark roasts are tricky, and compared to the 80's and 90's nobody's roasting that dark anymore ... in my humble opinion the trick is to produce a little oil on the bean while its in the roaster but in a commercial roaster you get a sample and if you spot any oil on a single bean you can bet that 10% or more of your roast has that same oil, i cant speak to what it might be on a home set-up ... closest ive come is the old jabez-burns sample roasters and our current pinhalase (sp?) sample roasters and they move through the roast a bit faster!

Mark

One coffee I enjoy at this level roast is Paradise Espresso decaf. I buy the green beans from Paradise - roast in my RK drum just into 2nd crack. It comes out slightly oily. For a non-espresso bean, this level roast probably would not show oil, but the decaf shows a little oil. It just makes a good rich tasting espresso - fine and chocolaty straight or in a latte - I like to draw about 2 1/2 ounces from 18 grams of coffee at 93 degrees Centigrade. (I know - I'm showing off my mini-Vivaldi a little). Actually, this makes a perfectly acceptable (to me) shot in my Gaggia Baby Twin from which I have no idea what the temperature is.