Others, more experienced, will likely chime in.

Regarding the process, you are preinfusing dark beans for 30s plus running a shot in normal parameters and you find the taste balanced, so it reads like you are extracting well, maybe even way too much, hah.

I have yet to try this, but have you attempted to use the paper filters that come with the robot? Those might help you as well. I'm staying away from them myself until I can get things consistent.

Meantime, some words for you to consider: Looking at your profile, you are new to espresso.

You need time for your palate to acclimate and ultimately calibrate. It may take weeks or months.

Regarding sweetness, in the words of Inigo Montoya, I do not think this word means what you think it does. Or quite likely it's me who doesn't know what it means. In the 2012-2018 period when I was most active with coffee, it meant balanced, not actually sugar. Back then we concerned ourselves with identifying the different acids in the coffee, like malic, phosphoric, citric, etc, and when balanced, you had a perception of a "sweet" coffee, but again, not really like sugar, more of a machination of it. I'm still catching up with today's scene and this word is thrown around a lot, not unlike "unctuous" in the foodie world. If you want your coffee a little sweeter, nothing wrong with adding a little sugar or some lactose free milk Of course, while learning, probably a good idea to hold off and explore these later. And finally, you may have prior experience with brewed coffee and learned to identify this word, or maybe the more experienced on this forum will point out the error in my ways, tbd.

Consider ignoring the literal meaning of the bag descriptions for now, just use those to help you gauge the coffee until you are consistent. If you want to tune your palate and learn the vocabulary, best to calibrate with others - find some friends locally to drink, triangle taste tests, or do the online thing and compare coffees with the folks here or on other forums. Some roasters will hold cupping sessions or similar events which can be fun.

Sorry for the long post, hopefully some is helpful.

jedovaty wrote:
Regarding sweetness, in the words of Inigo Montoya, I do not think this word means what you think it does. Or quite likely it's me who doesn't know what it means. In the 2012-2018 period when I was most active with coffee, it meant balanced, not actually sugar. Back then we concerned ourselves with identifying the different acids in the coffee, like malic, phosphoric, citric, etc, and when balanced, you had a perception of a "sweet" coffee, but again, not really like sugar, more of a machination of it. I'm still catching up with today's scene and this word is thrown around a lot, not unlike "unctuous" in the foodie world. If you want your coffee a little sweeter, nothing wrong with adding a little sugar or some lactose free milk Of course, while learning, probably a good idea to hold off and explore these later. And finally, you may have prior experience with brewed coffee and learned to identify this word, or maybe the more experienced on this forum will point out the error in my ways, tbd.
.

This is the best explanation of sweetness in coffee I have read. Thank you!

Some people do not perceive intense sweetness in coffee. Others say it's there. Who can argue with another person's perception? You can point to a list of the compounds in roasted coffee and say, "look, there's no appreciable quantity of sweet tasting molecules". But then another person says, "it tastes syrupy sweet to me". You can't argue with that. It's someone else's experience.

Human taste perception varies due to both genetic and environmental effects. Some people are very sensitive to bitterness while others are relatively tolerant. I think I'm in the latter camp. I find carrots and onions very sweet. They do have sugars in them but my wife thinks it's funny that I consider those vegetables sweet and prefer them to ice cream. Some of that is probably just how I am but it's also likely due to dietary choices.

I have had the experience of intense sweetness in coffee. The most recent time was two weeks ago. I had visited a small cafe in a tiny, tiny town in Australia, a place I had been to in the past. I knew they made good coffee but this time, with my first sip, I thought: "Did they put sugar in my coffee?" I knew there was no way they would do that. But it was unbelievably sweet. When I went to order a second cup I asked them about the beans, thinking I might go and buy some. Unfortunately they ordered them from another part of Australia, a good 2500km away.

They obviously weren't pulling shots with a Robot. That's not the point. They had dialed in the coffee well. And they had excellent beans. Sometimes at home with a particular bag of beans I get sweet shots easily. Other times it seems impossible. Occasionally I can coax it out of certain beans. But for me that sort of sweetness is an exceptional experience. Most of the time it's a more subtle thing that I am perceiving. But in my experience, with my limited set of equipment and skills, I find the bean matters the most. Along with grind, dose, ratio, temperature, etc., the beans (greens, roast, age) are probably the most important set of variables.

The coffee I'm drinking right now I brought home with me from Australia from a roaster there that I am familiar with. While there, using my Aeropress, I had gone through all but 50g of a small bag of a certain blend from that roaster without getting a really good cup. I left the remains of it in the trash of our hotel. But the espresso blend I brought home is quite good. It just hasn't been sweet... until this morning. I finally got a sweet cup. Not crazy sweet, but noticeably better. I up dosed and ground coarser and also lowered the temperature a bit. I've got a kilo of beans so I'll have plenty of time to try and make further improvements.

Interestingly, that second cup of coffee I ordered from the little cafe in Australia wasn't really very sweet. Had they pulled it less optimally? Or had my palate shifted? Who knows. But the first cup was truly wonderful!

Very Interesting and very helpful. Thank you both.

Truth is I don't know what a "good" or "sweet" espresso tastes like because I have yet to have one. I am chasing an idea of what I want it to taste like which may or may not even be possible. I am also very very hard on myself, because the shots I am pulling are way better than any shop, but I just have this feeling I can make it better by making it sweeter.

At this point I am thinking it's time to try another bean and see what I can do with it, as well as experiment with the Turbo Shot concept.