How to Increase Sweetness with Cafelat Robot

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by mbroder »


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.


#2: Post by macal425 »

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.


#3: Post by jpender »

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.

mbroder (original poster)

#4: Post by mbroder (original poster) »

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.
You are talking specifically for the Robot you do this? Do you pre-heat the basket and piston? ( I always do).


#5: Post by jedovaty »

+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 :)


#6: Post by jpender »

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.


#7: Post by jedovaty »

Yup, but, doesn't hurt to try and experiment. Worst case, you don't like it and spit it out, move on.

mbroder (original poster)

#8: Post by mbroder (original poster) »

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.


#9: Post by jedovaty »

Honest question, not intended to be rude: what makes you think the coffee you are brewing can be "sweeter"?

mbroder (original poster)

#10: Post by mbroder (original poster) »

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.