Something to play around.

The paddle GS3 CG discussion got me thinking. Apparently they got good results by using a low pressure long preinfusion thanks to the paddle lever. So I did something similar this morning.

My expobar brewtus has a very smooth water output but I don't know if this would work with all machines. I turn the pump on for 1 second and turn it off. Wait 8 seconds to soak the grounds. Then I pull the shot (~27 seconds). I know I didn't over do the preinfusion because flush water doesn't come out .

The flavor is different and if my mind doesn't do me a trick, I think it is sweeter.

I am not claiming that I get the same results as a GS3 or anything like that. Just playing.

Cheers

Interesting that you got anything drinkable from that. Simply pulsing the pump will open the 3 way valve and dump what water you did get in the group right out the valve. The rapid decompression from brew to off will also suck the puck up and destroy your coffee cake.

Your are simulating the pre infusion that the GS3 uses which is quite different than a paddle group. It pulses the pump for a couple of seconds then goes into standby while the puck saturates. Difference there, they keep the 3 way valve closed, then the pump kicks in for the full extraction. To do that on your machine, you would need to put a bypass switch on the 3 way valve so you can turn turn it off, then pulse the pump, then run the shot and turn the bypass back off so you get the pressure dump at the end of shot.

No, it doesn't dump all water. I can even pull the portafilter out and watch how the remaining water soaks up the puck (~30 seconds). The water comes out very gentle from the screen, and does not destroy the coffee cake at all. It never reaches high compression because I only do it for one second. And as I said, I don't see water being flush out.

Perhaps I get that because I never fill the basket over the line. Anyway, the flavor is good.

Cheers

PS: not sure it it would help. But maybe trying a double dose in a triple basket may give you a greater time clearance for preinfusion

cannonfodder wrote:Interesting that you got anything drinkable from that. Simply pulsing the pump will open the 3 way valve and dump what water you did get in the group right out the valve. The rapid decompression from brew to off will also suck the puck up and destroy your coffee cake.

Dave, the control lever of the Brewtus allows three positions, the middle position neither activates the pump nor the three way valve, so this is possible without disturbing the shot.

Hello, What is the feature of the paddle grouphead vs other styles? All I know is the "saturated head" mounts on the boiler. - Dennis

Hi Dennis.

Take a look here: http://www.coffeegeek.com/forums/espres ... nes/426628

If anybody has problems with preinfusion you can try this improvised dirty trick (never actually tried). On the shot glass pour some water from the water wand. Then carefully put some of this water on your loaded portafilter and wait a few seconds till some of it soaks up the puck. Then lock the portafilter in place. You may not get exact preinfusion temp but it may help to discover the effect of preinfusion for those that cannot otherwise do it.

Cheers

danetrainer wrote:Dave, the control lever of the Brewtus allows three positions, the middle position neither activates the pump nor the three way valve, so this is possible without disturbing the shot.

Thats right, I was thinking electronic for some reason, sorry about that.

The preinfusion you get from a paddle is actually more like a lever machine with a gentle pressure ramp, if you gently slide the paddle from one side to the other. The E61 group with a vibe pump has a very gentle pressure ramp unlike most rotary machines which hit full pressure in one or two seconds. The machine essentially has a paddle group pressure profile to start with. But there is nothing wrong with playing with parameters. If you like the coffee, that is all that matters.

Arpi,

You have a rotary pump, don't you? Are you using a water line or a tank? If you're hooked up to line pressure, you shouldn't need to activate the pump to soak the grinds. You should be able to hold the lever in the middle/slightly up position such that it opens the 3-way valve on the grinds but doesn't engage the pump, allowing water in at line pressure. That will give you super-gentle, moderately adjustable preinfusion. Pulsing the pump is probably safe, but certainly an added risk. On my T1 (which has no gicleur chamber for gentle preinfusion) I have a delay-timer on the pump so that the 3-way valve opens prior to the pump going. Similar thing. I haven't played with long preinfusion, but a modest amount certainly makes it easy to pull more consistent shots without having any negative impact on the shot that I can tell.

This reminds me of something I posted in an old thread, The Secret Life of Ristrettos:

HB wrote:As a rule of thumb, ten seconds of (extra) preinfusion equals a grinder adjustment of two millimeters coarser on the Mazzer Mini, or a reduction of coffee equal to approximately 1.5 grams (*). Running the mega-sized preinfusion "softens" the puck and opens a wider window for good extractions. My results so far for ristrettos are improved, though the opposite occurred for regular doubles, where the flavors became muddy and flatter.

To distinguish this from Rafael's on/off approach, I refer to them as preinfusion (some pressure) and prewetting (no pressure). My guess is that the worse the grouphead's initial water diffusion and the worse the barista's technique, the greater the benefit of the "enhancement" offered by manual preinfusion/prewetting. Why designers/baristas choose to focus on correcting the problem after it's already happened rather than preventing it in the first place is another question.

PS: For those who are wondering about E61 prewetting/preinfusion possibilities but aren't following the discussion points above, see Is there a purpose for the E61 middle brew lever position? for details.

shadowfax wrote:Arpi,

You have a rotary pump, don't you? Are you using a water line or a tank? If you're hooked up to line pressure, you shouldn't need to activate the pump to soak the grinds. You should be able to hold the lever in the middle/slightly up position such

The problem with that is that in the middle position I don't have any feedback and I don't know if water is coming out or not. There is no indication on the lever and cannot tell by feeling either. That location is not that obvious to get and it is very close to activating the pump. I would not be able to control the soak time unless I put my ear very close to the group head and listen to water noises. It can be done but it is harder for me.

The little added pressure of the on/off trick seems to help me more and I get a sweeter effect. I tried this morning the trick about adding water from the water wand but I think I didn't let it soak long enough and it wasn't like the others.

Cheers