How to Increase Sweetness with Cafelat Robot
Hi,
After many sub-optimal shots with Medium and Dark Roasts I finally figured out that a long pre-infusion (30 seconds) made the cup a lot clearer and reduced this harshness I was getting (probably a mix of under and over extraction due to channeling). I am now pulling shots that are pretty good, but I would not characterize them as having any sweetness.
Right now the recipe is
-Niche Grind Setting 15
-Water temp 211 degrees F
-17 grams in 35 grams in the cup
-2 bar pre-infusion and hold once I see a drip, 30 seconds later a very slow ramp to 6 bars
Any tips on how to bring out sweetness would be greatly appreciated.
After many sub-optimal shots with Medium and Dark Roasts I finally figured out that a long pre-infusion (30 seconds) made the cup a lot clearer and reduced this harshness I was getting (probably a mix of under and over extraction due to channeling). I am now pulling shots that are pretty good, but I would not characterize them as having any sweetness.
Right now the recipe is
-Niche Grind Setting 15
-Water temp 211 degrees F
-17 grams in 35 grams in the cup
-2 bar pre-infusion and hold once I see a drip, 30 seconds later a very slow ramp to 6 bars
Any tips on how to bring out sweetness would be greatly appreciated.
You could try lowering the temperature. I go down as low as 188 for a darker roast. 211 seems very high for a medium/dark roast. They usually do better with lower temperatures.
In a Robot that hasn't been preheated in some way the temperature of the water declines very quickly after pouring it into the basket. Water at 212°F in the kettle will drop to 200° or less before you even get started with preinfusion. Thirty seconds later it might be at 180°.
I'm not saying that starting with a lower temperature couldn't have a positive effect, just that the temperature profile of an unheated Robot is already shifted lower and has a relatively steep decline built in.
I'm not saying that starting with a lower temperature couldn't have a positive effect, just that the temperature profile of an unheated Robot is already shifted lower and has a relatively steep decline built in.
You are talking specifically for the Robot you do this? Do you pre-heat the basket and piston? ( I always do).macal425 wrote:You could try lowering the temperature. I go down as low as 188 for a darker roast. 211 seems very high for a medium/dark roast. They usually do better with lower temperatures.
+1 on trying lower temperature.
I have had a robot for a couple weeks, and been working on trying to dial in a darker roast. I don't generally care for darker roasts, being sensitive to the "roasty" flavor, but, it's been recommended to try since they are supposed to be easier to dial in. Earlier this week I finally had some success. Each shot had a strong, pith-like bitter taste at the finish. Then, on accident, I poured in water that was 200-203F range, resulting in a surprisingly delicious shot. This result has been repeatable for last few days. It was surprising to see how 5-10F made such a difference.
Despite what many are saying about using full boiling water and the temperature drop off with the robot, maybe do give a try for something between 200-205, see if it helps you, and please report back
I have had a robot for a couple weeks, and been working on trying to dial in a darker roast. I don't generally care for darker roasts, being sensitive to the "roasty" flavor, but, it's been recommended to try since they are supposed to be easier to dial in. Earlier this week I finally had some success. Each shot had a strong, pith-like bitter taste at the finish. Then, on accident, I poured in water that was 200-203F range, resulting in a surprisingly delicious shot. This result has been repeatable for last few days. It was surprising to see how 5-10F made such a difference.
Despite what many are saying about using full boiling water and the temperature drop off with the robot, maybe do give a try for something between 200-205, see if it helps you, and please report back

The OP mentioned medium as well as dark roasts.
Depending on the specific coffee I have sometimes noticed improvement by lowering the temperature of the water and sometimes by increasing it via preheating. Other times I have found that adjusting the temperature didn't really have much of an impact.
In general with darker roasts you want to use a lower temperature and extract faster. Maybe do a very short preinfusion or none at all. But not all dark roasts are the same.
Depending on the specific coffee I have sometimes noticed improvement by lowering the temperature of the water and sometimes by increasing it via preheating. Other times I have found that adjusting the temperature didn't really have much of an impact.
In general with darker roasts you want to use a lower temperature and extract faster. Maybe do a very short preinfusion or none at all. But not all dark roasts are the same.
Yup, but, doesn't hurt to try and experiment. Worst case, you don't like it and spit it out, move on.
Upped does to 18 grams in 36 grams out.
Dropping the temp to 200 definitely helped enhance the positive flavors, but still no sweetness.
I am certain my puck prep is not the issue (btw I find spraying the puck with water helped a lot just a few days ago)
What I have discovered with these beans is that a shorter or no pre-infusion caused either sourness or a mix of sour and bitter under various methods (meaning various grind setting, pressure profiling...any variation I could think of) I am thinking this was primarily caused by channeling which is why pre-infusion helped so much.
I concluded this after seeing how a long pre-infusion of 30 sec would give me such a big leap in taking out the negative flavors, something I avoided as I was concerned about overextraction. With the long pre-infusion it tastes...good... except no sweetness at all. I wouldn't say bitter, just rich and complex but lacking this sweetness that I am aiming for.
I did a very slow ramp up from the pre-infusion to 6 bar. At this point I will experiment with a lower dose and longer pre-infusion and various pressure profiles but I have a feeling I'm not gonna make any progress in search of sweetness. I also plan on working with a different bean (haven't even started playing with light roasts yet) but I feel like switching beans is analogous to throwing in the towel.
I wont share all the data and results but it is bountiful and meticulous ( over the last 2 weeks I have filled a whole notebook with notes and data working with two different beans). I am very new to this but I have done A LOT of research and reading. Maybe 50 hours of study (between reading articles and watching vids). Maybe 100 cups of experimentation. I realize now this is a life-long discipline that mixes chemistry with martial arts and ballet.
Dropping the temp to 200 definitely helped enhance the positive flavors, but still no sweetness.
I am certain my puck prep is not the issue (btw I find spraying the puck with water helped a lot just a few days ago)
What I have discovered with these beans is that a shorter or no pre-infusion caused either sourness or a mix of sour and bitter under various methods (meaning various grind setting, pressure profiling...any variation I could think of) I am thinking this was primarily caused by channeling which is why pre-infusion helped so much.
I concluded this after seeing how a long pre-infusion of 30 sec would give me such a big leap in taking out the negative flavors, something I avoided as I was concerned about overextraction. With the long pre-infusion it tastes...good... except no sweetness at all. I wouldn't say bitter, just rich and complex but lacking this sweetness that I am aiming for.
I did a very slow ramp up from the pre-infusion to 6 bar. At this point I will experiment with a lower dose and longer pre-infusion and various pressure profiles but I have a feeling I'm not gonna make any progress in search of sweetness. I also plan on working with a different bean (haven't even started playing with light roasts yet) but I feel like switching beans is analogous to throwing in the towel.
I wont share all the data and results but it is bountiful and meticulous ( over the last 2 weeks I have filled a whole notebook with notes and data working with two different beans). I am very new to this but I have done A LOT of research and reading. Maybe 50 hours of study (between reading articles and watching vids). Maybe 100 cups of experimentation. I realize now this is a life-long discipline that mixes chemistry with martial arts and ballet.
Honest question, not intended to be rude: what makes you think the coffee you are brewing can be "sweeter"?
No worries at all.
One bean says hints of berries, chocolate, and citrus, which is how it tastes. The other says Vanilla, Cocoa powder, and Cinnamin.
I assumed all coffees have more or less the ability for sweetness? Is that not correct?
Perhaps this coffee cannot be sweeter. I mean it tastes better than the espresso at the shop I bought it from. I cant seem to find any shops that make a good cup ( I live in Maryland close to Washington DC). I assumed this is because the time and care needed to make a good cup doesn't translate when it comes to the volume needed to thrive in a commercial setting.
One bean says hints of berries, chocolate, and citrus, which is how it tastes. The other says Vanilla, Cocoa powder, and Cinnamin.
I assumed all coffees have more or less the ability for sweetness? Is that not correct?
Perhaps this coffee cannot be sweeter. I mean it tastes better than the espresso at the shop I bought it from. I cant seem to find any shops that make a good cup ( I live in Maryland close to Washington DC). I assumed this is because the time and care needed to make a good cup doesn't translate when it comes to the volume needed to thrive in a commercial setting.