Do you get any drops using 1 bar pre-infusion?

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GregoryJ
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#1: Post by GregoryJ »

I'm using a Pro 800 spring lever with medium to dark roasted coffees. I usually hold the lever down ~10 seconds before releasing. When I'm at a reasonable grind size, I never see first drops with the lever in the down position (which is boiler pressure, ~1 bar, preinfusion). If I preinfuse for 40-60 seconds, or the grind is way too coarse, then I would see some drops.

For my typical shot, I hold the lever down for 10 seconds. Then I release the lever and gently guide it upwards and start to see drops on its way up, while I'm still holding it back for a little bit. The coffee comes out in ~20-40 seconds after I start raising it. Sometimes, with lighter roasts I will stop the lever on its way up to apply some preinfusion that is >1 bar but <11 bar (I believe that's around the peak for this machine). But, for my typical blends I just gently guide it, which I find is more repeatable and less prone to channeling than if I were to let the spring slam the espresso puck.

I'm not looking for any fix or solution, I'm just curious what others see. If you have a dipper machine or use a similar low pressure for preinfusion, do you see drops during the preinfusion phase?

Splatcat
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Joined: 3 years ago

#2: Post by Splatcat »

I'm set to just over 1.2 bar and I've been leaving my lever down almost a full minute for 1st drops and I'm super happy with the results. I guess longer pre Infusions muddy the flavors, but I love it.

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Mad Scientist
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#3: Post by Mad Scientist »

OP, I'm doing exactly the same as you with my Northbound Solstice, Prana or Trimmer's Delight 15.25 g in 15 g VST basket.
“You haven't lived until you've lived with a cat.” Doris Day

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GregoryJ (original poster)
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#4: Post by GregoryJ (original poster) replying to Mad Scientist »

I'm going through 5 lbs of Northbound Prana right now :)

coyote-1
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#5: Post by coyote-1 »

I'm doing preinfusion on a ViaVenezia. I do it at 2 bar to start. If I've tamped correctly, within a couple seconds the pressure goes up by itself to 4 bar or so as the water gets into the grinds and they bloom. I leave it there unto the first drip emerges. This is usually at around ten seconds (depending on the roast, the grind, and the tamp). At that point I halt the flow, and let the grinds fully bloom for another ten or twenty seconds.

randytsuch
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#6: Post by randytsuch »

Prefusion with a expobar office modified so vibe pump is controlled via what is basically a digital dimmer.

Pump is set to low power and I start the shot. Pressure ramps up to around 2 bars and dripping starts around 15 secs from start of shot.
I record the data too, so this is from a shot I pulled recently.

Randy

Utking
Posts: 59
Joined: 9 months ago

#7: Post by Utking »

I'm seeing the same with my europiccola. Doesn't get any drops when preinfusing unless I do it for a minute or so..

I don't feel like I'm grinding too fine either. It's just the way it is :)

Sugarbeet
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Joined: 4 months ago

#8: Post by Sugarbeet »

I'm doing 10~15s preinfusion (usually 12) with Europiccola and I do usually get a single drop at around 10s mark. If I grind any finer it requires a gorilla pull and takes 60s.

However one drop is not equal another. I'd say I can tell if by the size of that drop and how quickly it emerges weather I've ground too coarsely or not. If the drop is big and falls with 5~6s it's definitely going to be a very weak short pull. With the drop happening around 10~12s mark it's fine. If the drop doesn't happenin at all... Its too fine for me.

I use the standard europiccola basket with 12g (sometimes 12.5g) of coffee. Light to medium roasts, declumped.

I preheat the group.

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baldheadracing
Team HB
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#9: Post by baldheadracing »

GregoryJ wrote:I'm using a Pro 800 spring lever with medium to dark roasted coffees. I usually hold the lever down ~10 seconds before releasing. When I'm at a reasonable grind size, I never see first drops with the lever in the down position (which is boiler pressure, ~1 bar, preinfusion). If I preinfuse for 40-60 seconds, or the grind is way too coarse, then I would see some drops.

For my typical shot, I hold the lever down for 10 seconds. Then I release the lever and gently guide it upwards and start to see drops on its way up, while I'm still holding it back for a little bit. The coffee comes out in ~20-40 seconds after I start raising it. Sometimes, with lighter roasts I will stop the lever on its way up to apply some preinfusion that is >1 bar but <11 bar (I believe that's around the peak for this machine). But, for my typical blends I just gently guide it, which I find is more repeatable and less prone to channeling than if I were to let the spring slam the espresso puck.

I'm not looking for any fix or solution, I'm just curious what others see. If you have a dipper machine or use a similar low pressure for preinfusion, do you see drops during the preinfusion phase?
It depends on how much of the puck you want exposed to water before raising the lever.

The puck is still dry in some parts even when the bottom of the basket has just started weeping across its entire bottom surface. The wetter the puck is, the less resistance it will offer to water when the lever is lifted, so the faster the subsequent extraction, all other things being equal.

One theory is that a few seconds of pre-infusion at low pressure swells the top of the puck enough to minimize puck prep issues - and possibly group water distribution issues. I don't know.

Please note that I am not saying that having the entire puck wetted before lifting the lever is necessary or desirable. Lengthening the lever-down phase is perhaps most useful for increasing shot volume. It can also affect the temperature profile, but that effect is probably ignorable in a commercial group with most shot parameters.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

bgn
Posts: 560
Joined: 17 years ago

#10: Post by bgn »

Glad to hear of other user experience with this. I use a Cimbali M20 dipper lever and a conical grinder (perhaps the biggest factor here). My boiler runs between 1 and 1.2 bar in it's cycle. I lock in and cock the lever then walk away with lever left down. My kettle is across the kitchen where I go and pour water into my cup and walk back. Probably thirty seconds. I rarely see drips on the tray as I slide my cup under except when my coffee is getting old, over two weeks from roast.