Light roast espresso with the Niche Zero - Page 4

Beginner and pro baristas share tips and tricks for making espresso.
Cranked
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#31: Post by Cranked »

I'll try changing the pressure.

Lagom mini does look appealing, not sure if I can handle the listed grind times for espresso...

I'm certainly not looking for extreme clarity or flavor separation, I just want to get a balanced shot with all the flavors there.

Blaine
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#32: Post by Blaine »

Hey there, I wanted to chime in with my thoughts. I have had my Niche Zero for over a year now and have consistently been able to pull great shots with light to medium roasts by pulling shots between 7 to 8 bars of pressure and adjusting the water temperature between 198-203 Fahrenheit.

I use the barista version of the Cafelat Robot for espresso and usually preheat with a pressurized basket for 2 minutes while I am prepping and then use the professional basket to pull my shots (using Cafek T-92 bottom paper filter cutout below the grounds at the bottom of the basket). I do WDT on all shots and live at ~6000ft above sea level.

For the recent Prodigal release of the Franco Castillo Geisha (Columbia, Washed), I used:
•Roasted 5/21, pulled between 5/31-6/4 after 10 days min of resting
•203 degree F water
•Preheat for 2 minutes
•17 grind size on NZ
•16.1 gram dose
•31.8 gram extraction
•31 seconds total shot time, of which 10 seconds were pre-infusion
•7-8 bars of pressure

When I used this profile, the resulting shots were incredibly sweet and fruity with no astringency or bitterness.

Another recipe I recently used was for a coffee roasted by Corvus Coffee Roasters, which was their Hacienda La Papaya offering:
•Roasted 5/2, pulled between 5/15-5/23
•198 degree F water
•Preheated for 2 minutes
•~20.4 grind size on NZ
•16.1 gram dose
•33.3 gram extraction
•31 seconds total shot time, of which 8 seconds were pre-infusion
•8 bars of pressure

Again, the resulting shots from this profile were sweet with no astringency or bitterness.

FineGrinder (original poster)
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#33: Post by FineGrinder (original poster) replying to Blaine »

Thanks for your detailed recommendations. I also have found the lower doses (15-16g) work best along with hotter temperatures and the use of paper filters makes a significant difference.

What is the rationale behind lowering pressure from 9 bars? Is it because it's reducing channeling with lighter roasts?

Blaine
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#34: Post by Blaine »

Gladly, I hope they help!

I run 7-8 bars of pressure (usually) for a few reasons.

Firstly, Paul Pratt (the Robot maker) recommends a lower pressure profile between 6-7 bars for the Cafelat Robot. While I never pull at 6 bars, I regularly pull at 7.

Secondly, in my testing, shots that I pull between 7 and 8 bars are generally better tasting than those of higher pressures for all levels of roasts. The closer to 9 bars I get with traditional shots, the more astringency there is in the cup. Sprometheus found similar results favoring 7-8 bars in his video titled "Espresso Anatomy - Exploring Brew Pressure."

Thirdly, I experience less channeling at reduced pressure with traditional shots. However, pre-infusing shots mostly negates visible channeling (as does WDT). Notabky, I enjoy pulling blooming shots with lighter roasts where I will pre-infuse at 2 bars for 20 seconds, followed by no pressure for the next 20 seconds, and ramp up to 9 bars for the final 15-20 seconds.

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Jeff
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#35: Post by Jeff »

"9 bars" is an outdated decision based on 1950s coffee and pump-driven machines.

Even for cafe-style espresso, there has been a realization that lower pressures can result in more enjoyable espresso.

My observations, for medium and lighter roasts, have been that peak pressures over around 8 bars or so can be "flat" to bringing out cardboard flavors. Most of my shots are pulled in the 4-6 bar range, in the basket.

Some of this may be related to what some call "secondary compression". Somewhere around 8 bars the bed starts to behave in an unexpected way. More pressure results in less flow. This suggests that the way the water and then coffee moves between the particles change. Staying out of a hypothesized "congested flow" region is believed by many to improve the espresso, especially for lighter roasts.

Blaine
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#36: Post by Blaine »

Jeff

Thanks for that insight, it likely explains why 9 bars sometimes feels more difficult to pull on the Robot and why there is less flow than 7-8 bar shots. The resistance must be coming from this congested flow zone, which i feel is noticeable on a lever machine. Always glad to learn something new and further explains why I naturally gravitated to less pressure and is possibly why Paul suggests it.

FineGrinder (original poster)
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#37: Post by FineGrinder (original poster) »

I'm going to give that video a watch and definitely tinker around with lower pressures.

I tried pulling a shot at 8 bars (keeping all other variables the same) and to my surprise, it flowed much faster and ended much quicker. It actually tasted better than my 9 bar shot with the longer contact time so I'm going to play around with lowering pressure even further and fine-tuning grind to compensate for changes in flow next.

It does appear that higher pressures may be increasing compression of the puck, inhibiting flow, and increasing the likelihood of channeling.
Blaine wrote:Gladly, I hope they help!

I run 7-8 bars of pressure (usually) for a few reasons.

Firstly, Paul Pratt (the Robot maker) recommends a lower pressure profile between 6-7 bars for the Cafelat Robot. While I never pull at 6 bars, I regularly pull at 7.

Secondly, in my testing, shots that I pull between 7 and 8 bars are generally better tasting than those of higher pressures for all levels of roasts. The closer to 9 bars I get with traditional shots, the more astringency there is in the cup. Sprometheus found similar results favoring 7-8 bars in his video titled "Espresso Anatomy - Exploring Brew Pressure."

Thirdly, I experience less channeling at reduced pressure with traditional shots. However, pre-infusing shots mostly negates visible channeling (as does WDT). Notabky, I enjoy pulling blooming shots with lighter roasts where I will pre-infuse at 2 bars for 20 seconds, followed by no pressure for the next 20 seconds, and ramp up to 9 bars for the final 15-20 seconds.

FineGrinder (original poster)
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Joined: 1 year ago

#38: Post by FineGrinder (original poster) »

Thanks for the insight. I am going to play around with lowering pressure, especially for lighter roasts and see how that affects flavour. Maybe it's not coincidental that I've had some of my best light roast shots as 6 bar turbo shots with a low dose using the Niche.

Do you feel 9 bars still has value for darker roasts considering it was historically used for that style of coffee?
Jeff wrote:"9 bars" is an outdated decision based on 1950s coffee and pump-driven machines.

Even for cafe-style espresso, there has been a realization that lower pressures can result in more enjoyable espresso.

My observations, for medium and lighter roasts, have been that peak pressures over around 8 bars or so can be "flat" to bringing out cardboard flavors. Most of my shots are pulled in the 4-6 bar range, in the basket.

Some of this may be related to what some call "secondary compression". Somewhere around 8 bars the bed starts to behave in an unexpected way. More pressure results in less flow. This suggests that the way the water and then coffee moves between the particles change. Staying out of a hypothesized "congested flow" region is believed by many to improve the espresso, especially for lighter roasts.

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doug
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#39: Post by doug »

DE1XL & NZ for a long time, though I've switched to a DF83 this year. I prefer light to medium light espresso too, and especially anything complex with multiple flavors in the cup.

I did not have to go with a lower dose or filter paper, and just always use 17g (WDT, level, tamp, puck screen), but I continue to tweak the flow rate for the beans I'm on to get a very long preinfusion phase with just a few drips before jumping to a long 8bar declining pressure / flow profile to keep the flow out the bottom fairly slow and uniform for 28-32s to make 36ml. Or that's my goal, but with each different roast I normally have to change the profile shape a little, and sometimes cut it off a bit earlier. And I vary the temperature to find the flavors I want, but have not tried a declining temperature profile.

Even with the Niche, I had no problems getting peach, jasmine, and a couple other flavors out of a good Ethiopian like the Atomic Kochere, or blueberry, cacao, baking spice notes out of some central American espressos. My only gripe with the Niche was that the shots had plenty of body and I was hoping for more clarity to pick up even more complex flavors. The DF83 did add some clarity, even though it still has a lot of fines, but that particular grinder is a bit more inconsistent when trying to dial it in. It also has some often discussed exit chute issues. So perhaps the 78S you preordered will provide good flat burr clarity while keeping the simple workflow of the Niche when you get it in August or September.

FineGrinder (original poster)
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#40: Post by FineGrinder (original poster) replying to doug »

Thanks for sharing your experience.

How did you tweak your flow rate during pre-infusion? I normally have 4ml/s until it hits 4 bars of pressure and then goes into the main extraction phase, which is how the default profile is programmed I think. That usually gives me about ~7s of pre-infusion. Do you extend it by dropping it down to 3ml/s or lower or by setting a higher exit pressure?

I do find the lack of clarity with the Niche is not really to my preference but I cancelled my 078s pledge. There were mixed early reviews with some even saying it's not particularly clarity-forward so I've decided to hold out and may end up going with a Niche Duo, which at least gives me a range of SSP burr options, or possibly some other flat burr grinder.