After having tried to explain how I use the flow control on my E61 a few times I finally broke down and shot a video. For the first year I left it set in the default flow position and didn't really use it. Partially because I never found any great tutorials or videos of a good methodical approach to implementing it. After a year of learning a few things emerged.

1) The highest flow rate an espresso puck can absorb water at is about 4ml/sec
2) The goal of pre-infusion is to allow the puck to absorb water under less demanding conditions and to get the top and the bottom of the puck wet as close as possible in time, otherwise you create an uneven extraction gradient.
3) The puck undergoes primary compression around 4bar. After this we are clearly past the pre-infusion point so this is the place to transition to full flow.

The way I've been using my flow control is to start from known flow rate positions (usually 3-4ml/sec) and then watch the bottom of the puck, the group pressure gauge and the scale to judge when and how quickly to increase the flow to a full 7.5ml/sec. In this example I start from a position that gives me ~3ml/sec flow and then wait until the puck reaches 4 bar before turning the flow control to the 7.5ml/sec position.

I should note that this is a fairly light roast Ethiopian coffee from Escape in Montreal and I'm using a Monolith Flat grinder. Both of which are difficulty multipliers. I'm not exactly thrilled with this particular shot as doing all of this with a camera on a tripod and a light stand next to it really makes things awkward. None the less I thought others may find this useful when trying to develop their own flow control techniques.

Thanks for this, I'm currently trying to read/ watch all I can about flow control on an e61, I just ordered a QM Carola with flow control, and hope I'm not trying to learn too much at once.

That is pretty much exactly what I have settled on for the great majority of my light SO drinks.

Darker roasts or blends used for milk drinks have it start at the 7 m/sec and when flow is fully established I gradually decrease the flow rate.

Your video was very instructive for me, as I had never seen an actual video of a shot pulled with a flow control mushroom.

What I did learn is that it confirmed my suspicion/intuition that flow control mushrooms are not for me. That I prefer line level preinfusion with our machine direct plumbed & drained and tweaking the water line preinfusion pressure with the water pressure regulator that's at the output of the water filter.

Your video also clearly illustrates the difference in sound between a vibe & rotary pump.

Thank-you for posting, as I learnt a lot in less than 1-minute!

BaristaBoy E61 wrote: What I did learn is that it confirmed my suspicion/intuition that flow control mushrooms are not for me. That I prefer line level preinfusion with our machine direct plumbed & drained and tweaking the water line preinfusion pressure with the water pressure regulator...

I should point out that this approach does not get you the same controls or feedback as a flow control kit. In order to accurately see when, in real time, the puck reaches that 4bar compression you need a group head mounted pressure gauge. Additionally, a rotary pump will often have a very high flow rate of 10-12ml/sec and without an adjustable needle valve on the mushroom you have no way of bringing that back down to a more puck friendly 7-8ml/sec.

I agree that using a two position flow state gets you a lot of benifit. If you prefer using a control on the line pressure to set 3-4ml/sec that's workable. But you'd still benifit from having the kit installed to get both the accurate and fast acting pressure gauge that's reading where it matters (at the puck) and the ability to limit the maximum flow rate of the pump to a more sensible 7-8ml/sec.

One other thing not illustrated in this video that you can do with a flow control kit is to taper off the flow towards the last third of the shot as the puck erodes and you have a natural increase in flow and potential increase in channeling and the associated uneven extraction.

I should also note that a lot of what I'm implementing here are things we've learned about espresso from people using the Decent espresso machines/calculators. The data they've generated can be implemented by other hardware (at least within limits) with a little thought about what is now known about best practices for puck stability and how it influences even extraction.

Very nice video--thanks for posting!

PIXIllate wrote:I should point out that this approach does not get you the same controls or feedback as a flow control kit. In order to accurately see when, in real time, the puck reaches that 4bar compression you need a group head mounted pressure gauge. Additionally, a rotary pump will often have a very high flow rate of 10-12ml/sec and without an adjustable needle valve on the mushroom you have no way of bringing that back down to a more puck friendly 7-8ml/sec.

I agree that using a two position flow state gets you a lot of benifit. If you prefer using a control on the line pressure to set 3-4ml/sec that's workable. But you'd still benifit from having the kit installed to get both the accurate and fast acting pressure gauge that's reading where it matters (at the puck) and the ability to limit the maximum flow rate of the pump to a more sensible 7-8ml/sec.

One other thing not illustrated in this video that you can do with a flow control kit is to taper off the flow towards the last third of the shot as the puck erodes and you have a natural increase in flow and potential increase in channeling and the associated uneven extraction.

My experience has been such that my 'Tools', being grind, dose, tamp pressure, Stop Watch, Line Pressure Preinfusion and back to Line Pressure 'Post-infusion' or tapering off, along with water line regulation, Naked Portafilter and Shot Mirror are plenty. Gets me to great tasting espresso. The Shot Mirror and Naked Portafilter provide all the feedback needed to determine when to 'Shift Gears' and when to kill the Shot.

More than that, for me, would be either a LM GS3MP or a KvdW Speedster Idromatic.

BaristaBoy E61 wrote: My experience has been such that my 'Tools', being grind, dose, tamp pressure, Stop Watch, Line Pressure Preinfusion and back to Line Pressure 'Post-infusion' or tapering off, along with water line regulation, Naked Portafilter and Shot Mirror are plenty. Gets me to great tasting espresso. The Shot Mirror and Naked Portafilter provide all the feedback needed to determine when to 'Shift Gears' and when to kill the Shot.

More than that, for me, would be either a LM GS3MP or a KvdW Speedster Idromatic.

If you have a routine that works for you and you like the espresso then I guess you're all set. The point of posting this video was to put forth a technique for manual pre-infusion based on the most up to date information about what is ideal for an even espresso extraction and how much of that can be achieved with common E61 machines and a relatively inexpensive flow control kit. I've looked around quite a bit and something like this demonstration does not seem to be out there.

Regarding the GS3MP, I have a friend with one. To be honest I find it to be more touchy and difficult to repeatedly hit pre-defined flow rates than the flow control E61 knob. That machine does offer greater temperature stability but again, the point of this thread was to demonstrate a method for pre-infusion.

BaristaBoy E61 wrote: I prefer line level preinfusion with our machine direct plumbed & drained and tweaking the water line preinfusion pressure with the water pressure regulator that's at the output of the water filter.

Ca you please tell me how you set that up?
On my machine, I put in the blind basket and adjust the OPV to display 9 bars. Do you do the same thing, only opening the valve for pre-infuse only and adjusting your water pressure regulator?
Then, you go back and check brew pressure?

This is my shot on an ECM Synchronika

Pre-infusion at 1/6th turn until pressure starts to build in the head, then 0.9 to 1.0 turns open.

https://streamable.com/8mcebc

18g in, 36g out in 25s (from first drop). MR Guatamala Huehuetenango

I see some unevenness at the start, or am I seeing things that aren't there. Feedback is very welcome.

Puck prep with WDT, leveler and tamp. IMS Basket. And yes, I magnetted the mirror to the hot water spout .

End result was, in my opinion, incredible. But I have not calibrated my taste with somebody more knowledgeable.