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.

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

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.

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.

Hello, The way I understand it, the new B 111R should utilize a water solenoid with the pump/motor so that water will not flow thru unless the pump is switched on. I have not confirmed this with WLL, though.
This would be a safety feature to prevent floods from different users and their practices.
Arpi, in the past, some Brewtus owners reported their mid lever position allowed water to flow thru, and some reported nada. Todd responded about a part inside the grouphead that is longer on some machines, not allowing the flow thru. If your unit is one of those, the part can be replaced with the piece that works.
On my B1, I converted to external pump/motor with plumb in and plumb out. Mine is converted "suicide style" with constant line pressure, and offers the manual preinfusion feature.
I have been reminded that our E-61 semi-auto lever boxes offer the best preinfusion feature compared to full-auto models. That is a plus. - Dennis

ps - Arpi, how's your back doing? Mine has been acting up for two months, now!

By converting an E61 lever into the same configuration as Dennis' (with one small addition), it allows you to experiment with "Paddle/Slayer" style pressure profiling.

So you want to make sure that:

1. Your E61 lever is hook up to an plumbed-in rotary pump (with built-in bypass valve).
2. No inlet (safety) solenoid is in the chain so that you are seeing line pressure at the group head.
3. Add an needle valve just up stream of the brew head

The needle valve allows you to tune your water debit. If you do not change the gicleur, the rotary pump ramps up to full pressure in about 2 seconds. By decreasing the water debit, you can tune your machine to have that "stock" gentle ramp up (~6.5 seconds) of an vibe-pump E61.

I also recommend putting a pressure regulator at the inlet of the rotary pump - this allows you to tune your line pressure.

When the lever is at off position, the group is closed and the 3 way is open. Turning the lever about 50~70 degrees (right before it engages the microswitch), the group opens, closing the 3-way, and allowing water to flow thru and ramp to line pressure. Engaging the lever fully (depressing the microswitch), the pump kicks in and it ramps from that line pressure to the set pump pressure. This allows for several possibilities in pre-infusions.

Toward the end of the shot, you can move the lever from 90 degrees back to about 80 degrees such that the microswitch is allowed to come to the off position. This kills the pump and the pressure will ramp down (~2 seconds) and hold at slightly above line pressure (approx 6~7 bar). This is similar to what Slayer is doing w/ their machine thought their ramp might be a bit more gentle/longer due to the smaller orifice in their "pre-infusion" position.

While this does not exactly offer full control over pressure profile, this simple/cheap setup does allowed for some play potentials. I have yet to have any conclusion on the reduced pressure toward the end of the shot or the extended pre-infusion at the beginning of the shot.

I checked with WLL tech support (cathy), and she indicated they did not use a water solenoid to control water fl0w thru with the lever in mid position.
Some time ago, I remenber Todd stating when a plumb in was applied, he would choose a solenoid for it.
Instead, WLL stated they instruct owners to adjust water line pressure to below 12 lbs so it doesn't push it's way thru the grouphead. - Dennis

I've been tinkering around with pre-infusion and my Silvia. What I do is leave the steam wand open, and then hit the brew switch. The pump ramps up and the steam wand acts as a pressure relief valve. Then by feel on the knob, I can tell how much pressure is in the system and fine-tune the relief valve nearly closed - i.e. pinch off the relief flow, which sends more flow to the grouphead. After about 10s, I close the valve fully and the extraction begins.

Rancilio Silvia Preinfusion Technique

--don

Hi Arpi, Have you tried boosting the line-in pressure? You will have to readjust the pumps bypass valve to your brew pressure. You should get faster preinfusion in mid lever position. Some folks go 25-35 lbs. inlet pressure. -Dennis