duckman Senior Member Joined: 30 Oct 2004 Posts: 95 Location: Las Vegas, NV Expertise: I love coffee
Espresso: Gaggia Carezza Grinder: Solis Maestro Plus Drip: Bodum Brazil, Kenya, and... Roaster: Wear-Ever PopcornPumper
Posted Thu May 5, 2005, 3:57pm Subject: Bitter scent different when caused by temperature vs. over extraction?
It is said that bitterness has many causes with two of them being 1) too high of a brewing temperature, and 2) overextraction. If the other causes (beans, machine cleanliness, time, volume, etc...) are known to be fine is it possible to single out the cause of the bitterness? If possible, I would think it would be hard to single out the cause if both are a factor.
Example: The puck was not packed correctly and therefore part was over extracted, and the temperature was too high. However, lets say the brew temperature is spot on and the cause of the bitterness is over extraction. Can we tell if the cause was due to over extraction and not due to a high temperature?
Basically what I am wondering is if the smell of a shot can be fine but be bitter on the tongue, or does bitterness always come out the same in the cup (via the scent) no matter the cause? Or, are these factors so intertwined (too high a temp is a form of over extraction?) that it is impossible to tell without trial and error?
Maybe that is why getting an excellent shot is so exciting. You know many things came in sync to form something so great! :)
jim_schulman Senior Member Joined: 19 Dec 2001 Posts: 3,772 Location: Chicago Expertise: I live coffee
Posted Thu May 5, 2005, 4:57pm Subject: Re: Bitter scent different when caused by temperature vs. over extraction?
If you get a taste of instant coffee, it's over extracted and you ned to grind coarser and make longer shots. I get this sometimes when I go over-ristretto (or is it under-ristretto).
Really high temperature bitterness is slightly burnt and accompanied by very dark to black crema. Every once in a while, I forget to flush the Tea before a shot, and bingo, an object lesson in this.
Normal tasting bitter flavors, but not properly balanced by others, means the temperature, while in proper espresso range, is a little too high for the blend.
If you suspect packing problems, there's now a perfect answer -- get a naked PF and make sure your levelling and tamping are up to snuff. In general, bad channeling will cause a whole host of problems -- odd looking pours even with a spout, too fast a pour, thinness, poor crema, and both over and underextracted tastes. The little spritz type channeling early in the shot that's obvious with a naked pf, and invisible with a regular one, just degrades the shot's taste without creating any eggregious flaws. This is where the naked pf is most useful, since it's virtually impossible to catch this flaw any other way.
duckman Senior Member Joined: 30 Oct 2004 Posts: 95 Location: Las Vegas, NV Expertise: I love coffee
Espresso: Gaggia Carezza Grinder: Solis Maestro Plus Drip: Bodum Brazil, Kenya, and... Roaster: Wear-Ever PopcornPumper
Posted Tue May 17, 2005, 2:33pm Subject: Re: Bitter scent different when caused by temperature vs. over extraction?
What I am getting is bitterness on the nose as well as the tongue, but I don't think it smells of instant coffee. My shots are of mid-range brown rather than a very dark crema. Every once in awhile I get a great shot but I haven't been able to get one consistently. Now that I'm thinking about it I get more liquid in one shot glass vs. the other which makes me think my tamping is really off. The other day I read something about not doing a pressure twisting polish (as it tears the surface?) so I have been trying that out.
Buying a 58mm tamper has really improved things from using the plastic one that came with my Gaggia. However, there still seems to be a small (about 1mm?) gap between the tamper and the edges of the pf.
It looks like the best thing to do is get naked pf and at least diagnose my tamping! :)
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