I've got an older Gaggia Classic and for some reason, the aroma of the espresso and the taste is sort of "burnt" for lack of another word. I'm currently using Kimbo and I've even experience the same issue using Illy. I've descaled it a couple of times, cleaned out the strainer and any easily accessable parts (not going in to the boiler of pumps) and still has this off flavor taste. I've used white vinegar to descale it and flushed it out at least 3 times (full tank). Any suggestions?

By burnt I assume you mean excessively bitter. This can be caused by high temperatures. Try pulling shots at a lower temp and see if that does it.

An easy test to confirm the cleanliness of your equipment: Draw some water through the group, let the water cool, and then taste it. Since the water was heated, it may taste a little "flat" compared to direct from the tap, but otherwise should have no off flavors.

Dickm wrote:I've got an older Gaggia Classic and for some reason, the aroma of the espresso and the taste is sort of "burnt" for lack of another word. I'm currently using Kimbo and I've even experience the same issue using Illy. I've descaled it a couple of times, cleaned out the strainer and any easily accessable parts (not going in to the boiler of pumps) and still has this off flavor taste. I've used white vinegar to descale it and flushed it out at least 3 times (full tank). Any suggestions?

Source some Citric Acid for descaling. Use 1 Tbs/quart of water. White vinegar isn't really up to the job.

The other thing that may be an issue is the path between the group and the 3-way valve. Try backflushing your machine with a detergent like Cafiza. If you don't backflush the Classic, that pathway gets a buildup of old coffee oils....

pacificmanitou wrote:By burnt I assume you mean excessively bitter. This can be caused by high temperatures. Try pulling shots at a lower temp and see if that does it.

How can you pull the shots at a lower temp? Yes, the flavor is excessively bitter. I know its not the coffee because I've made some using my stove top maker, and it's fine. The manual also mentions using a lower temp, but no instructions on how to do it. I'm pretty much a novice when it comes to using pump espresso makers, but, I got this REAL cheap and couldn't pass it up.

How can you pull the shots at a lower temp?

Not something you can really control on the Gaggia Classic unless you add a PID.
You can try temp surfing, which basically means trying to guess where the temperature is at any given moment along the 30-40 degrees of the brew stat's deadband, but that's .... problematic and I wouldn't be able to tell you how to achieve any success.

Kimbo is usually dark and has a high robusta content and in my experience inherently has burnt/bitter notes. I haven't used illy in a long time so I can't comment on its flavour profile.

I assume you're buying whole beans and grinding them yourself, if not, the pre-ground coffee is the problem.

What he said !!! How did we miss that point????
If you don't have a good espresso grinder and fresh beans then everything else is irrelevant.