A More Considered Approach to E61 Flow Control

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

I'll start by saying that in the 11 months since I bought my Profitec 600 with Flow Control it has mainly stayed in a position providing me with roughly a 7.5ml/sec water debit. I haven't really actively used it more than a handful of times. It seemed like each time I did start moving it I encountered a problem where flow would either be greatly restricted or stop completely no matter which position I put it in. Some of these issues were described here:

Profitec Pro 600 - No Pressure/Water from Group

Once I cleaned out the original debris everything seemed to work very well as long as I set the FC to 1-1/4 turns open and just left it alone. Each time I would try experimenting with it it would give me issues and then after a good wide open flush it would stabilize again.

Then a few weeks ago I saw a video from Bella Barista in reference to setting the flow control position on a Lelit Bianca:
In it there is mention of not setting the paddle in a position where the flow can be completely stopped. The reasoning given is that in order to do so the needle needs to be seated so tightly in the hole that mechanical damage can occur.

This got me thinking about the issues I had each time I used the FC on my E61, which I had set so the flow could be completely shut off. Remembering back, every time I started using it the first thing I would do would be to rotate it completely closed. I ran an experiment where I did exactly that. The flow immedatly became heavily restricted at all settings. After a minute of flushing with the FC in the fully open position things returned to normal whereby the 1-1/4 turn position was 7.5ml/sec.




I then tried closing the FC but NOT all the way. Stopping between the 1/4 and 1/2 turn positions. This gives me a flow rate of about 3ml/sec. I could then freely alternate between these two positions as many times as I wanted with no further slow down in flow.

Even though I haven't been using flow control I've been thinking about it and paying attention to discussions regarding it's use. Quite a few of these come out of the Decent machine and community. I was reminded about a comment in a video John from Decent made about the ideal low flow rate to saturate a puck as evenly and QUICKLY as possible.
The reasoning given is that if you do this too slowly you are wetting the puck more gently but you are also creating a gradient of how much time the grounds at the top of the puck vs the bottom of the puck spend in contact with the water thereby creating another kind of uneven extraction. He stated that the ideal flow rate for gently saturating the puck in the shortest amount of time was between 3-4 ml/sec.

It then occurred to me that I could possibly combine a few things together. By setting the FC to a postion where I got 3ml/sec (just short of 1/2 turn open on my machine) and then loosening the knob I could let it seat itself against the top of the mushroom thereby both preventing the valve from closing completely and giving me an easy, repeatable position to use for pre-infusion.




If I want 4ml/sec instead of 3ml/sec I just start at the half turn position.

I tried a few shots like this today as I currently have a coffee I'm finding a bit bright. I think the pre-infusion improved the coffee and I found it quite easy to accurately alternate between the two flow rates shot after shot. I did retest the water debit at both positions when I was done and it was exactly the same as when I started.

I do acknowledge that this does NOT allow for long blooming phases in shots but that may be a problem for another day.

I'd be interested to hear thoughts about this approach from other people who own and use E61 machines with flow control. In particular the ECM/Profitec style control.
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cgibsong002

#2: Post by cgibsong002 »

Great post, thanks! Curious to hear more feedback as it seems so much of this profiling data is limited to Decent users and so little info from E61 flow control users. Strange considering how popular the Bianca is.

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PIXIllate (original poster)
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#3: Post by PIXIllate (original poster) »

I wonder how many people with manual flow controls actually use them for a majority of their shots. I guess I'll have to see if this new setup leads me to tinker more often.

boren

#4: Post by boren »

For shots where you don't use the flow control and just leave it in one position, doesn't that mean that you give up pre-infusion? If so, isn't that likely to produce worse espresso than without this control insalled, given that E61 grouphead have built-in pre-infusion?

PIXIllate (original poster)
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#5: Post by PIXIllate (original poster) »

I did not replace the bottom spring on my machine so I have the exact same e61 preinfusion as a stock machine at the expense of a little less control over a faster ramp up time on some VERY specific profiles that may call for this.

walr00s
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#6: Post by walr00s »

PIXIllate wrote:
In it there is mention of not setting the paddle in a position where the flow can be completely stopped. The reasoning given is that in order to do so the needle needs to be seated so tightly in the hole that mechanical damage can occur.

This got me thinking about the issues I had each time I used the FC on my E61, which I had set so the flow could be completely shut off. Remembering back, every time I started using it the first thing I would do would be to rotate it completely closed. I ran an experiment where I did exactly that. The flow immedatly became heavily restricted at all settings. After a minute of flushing with the FC in the fully open position things returned to normal whereby the 1-1/4 turn position was 7.5ml/sec.
I literally completely close my flow control every shot, sometimes twice (during PI and near end of shot). Haven't experienced anything like what you describe regarding flow rate yet, nor any perceptible damage.

Auctor
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#7: Post by Auctor »

I definitely think that the way the Bianca implements flow control is different than ECM. In this video, WLL claims that there's no damage caused by restricting flow to zero for a longer period of time, while admitting they didn't leave it off for minutes and minutes. While the Bianca may have some problems, this doesn't appear to be the case with the ECM implementation.

http://www.youtube.com/watch?v=Djx2C8yXYb4

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PIXIllate (original poster)
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#8: Post by PIXIllate (original poster) »

I'm certainly not ruling out that my flow control is damaged vs others but I highly doubt the needle valves are very different between manufacturers. Other than the knob/paddle that is connected to the top of them I'm not sure there are mechanical differences with the needle valve itself.

As the title says I'm trying to consider how to use the e61 flow control. Regardless of the issue of potential damage to the hardware the idea got me to think about how I might set it up so it could be more functional and repeatable. Both a Slayer and a GS3 have two main water debit positions that can quickly and reliably be selected almost mindlessly. My idea was that by setting a physical stop at a measured ideal pre-infusion flow rate it may make the feature more repeatable and therefore more functional.

From what I understand pre-infusion of the puck at a lower, slower flow rate promotes even extractions, higher yeilds and can facilitate better results with light roast coffees that require finer grinds to fully extract as espresso. This is based on water contact time, particle size and solubility. It would seem that the ideal flow rate for this has been figured out by Buckman's giant espresso calculator so why not take this information and adapt it to the control available to me?

In an attempt to keep this thread focused on how manual flow control can be used to make better tasting coffee, how do you guys use yours day to day? Do you dial in without it or dial in while looking for drips or a certain amount in the cup in a given time? I know that John Buckman and Scott Rao talk about ending pre-infusion based on pressure rising to 3-4 bar whether you see drips or not. This phenomenon is easily visable to me on my group pressure gauge and has given me the best results I have been able to achieve so far with the flow control.

Eiern

#9: Post by Eiern »

I use the paddle on my Bianca for every shot, but I keep it repeatable: paddle straight at me for the first ~15 seconds until max pressure is reached (I've set it to 6 bars for my unimodal/brew ssp burrs and filter roast) and when the pressure shows signs of going down again after a second or so I slowly (3-4 seconds) open the valve fully to maintain the max pressure until it starts going down again. Flow is roughly 3ml/sec in the middle position an ~6 ml/sec open. I get very clean, fully extracted balanced shots with this preinfusion, usually 24-26% (filtered measurement) 1:3 shots. I have tried many different preinfusions including and blooming profiles, but this one has been the best tasting so far and the most repeatable too.

PIXIllate (original poster)
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#10: Post by PIXIllate (original poster) » replying to Eiern »

This seems like a fairly reasonable routine. What roast level of coffees do you normally use? Do you vary the procedure for different coffees?

Here are some other threads where Bianca users are showing how their flow controls broke due to closing the needle valve completely.
Again, I can't imagine Lelit and ECM/Profitec are each manufacturing their own separate but nearly identical parts.

Lelit Bianca - Flow Control Hardware Issues
Lelit Bianca User Experience