Espresso Flow Download
Addison Mauldin
After some research, I decided to use a dark roast for this experiment, as it can provide more crema. In my research, some people recommended not to grind too finely to avoid clogging the valve, while others suggested grinding very finely to get a more espresso-like taste.
I ended the morning already overloaded with caffeine, ready to do more experiments in the coming days, but already extremely satisfied with the new Flow Control Filter Cap. I finally managed to extract espresso-like coffee with the AeroPress! But I also managed to improve on the classic AeroPress experience.
The giggler (sometimes spelled gicleur or gigler) may be missing or otherwise damaged on the refurbed GB5. Check page 22 in the manual linked here. That piece is responsible for regulating flow rate to the grouphead, and not having it could produce the experienced condition.
Pressure drop down a tube can be thought of in much the same way - resistance to flow as the result of friction (i.e. drag)*. The greater the resistance, the greater the pressure drop for a given flowrate. In an espresso machine, it is the pressure drop that determines the backpressure at the pump (i.e. the pump discharge pressure).
@latte911 - interesting info in that guide from La Marzocco. Rather round numbers for the flowrates with the various different gicular sizes. Comparison with (predicted) pressure drop across just the gicular (i.e. excluding the rest of the system) is interesting:
While there are other ways to change grind size while keeping flow rate steady (dosing, tamping etc.), lowering water debit has the obvious advantage of wetting the puck more slowly and thereby enhancing evenness of extraction.
So my conclusion is that the ideal water debit allows for a slow saturation of the puck while maintaining the grind size fine enough to extract the coffee. In the end thats probably what pressure and/or flow profiling is about
My prep/setup includes WDT (with 0.4mm acupuncture needles) and an 18g ridged VST basket. Even when tamping askew to compensate for any potential slope, the shots still flow front of center. I thought it was just my prep for the longest time until my wife bought me a shot mirror for Christmas ?
I have always found it difficult to pull good shots from the machine. My shots are usually always unbalanced with a heavy bitterness no matter the grind size. This leads me to believe I am getting uneven extraction. The mirror is also showing me good flow from the front of the basket, but inconsistent/channeled flow closer to the rear.
In 2021, the Flow coffee telemetry system won the Ancillary Electrical Equipment award at the Melbourne International Coffee Expo (MICE) for its ability to integrate with espresso machines, provide feedback on every shot poured and help baristas improve their performance.
The AeroPress Flow Control Filter Cap's valve doesn't open until users begin pressing, creating a buildup of pressure that brews barista-worthy espresso-style coffee. No expensive espresso machine required!
The AeroPress Flow Control Filter Cap's valve doesn't open until users begin pressing. This creates a buildup of pressure that brews barista-worthy espresso-style coffee. The pressure-sensitive valve stops all drip through so that users can extend their brew times and control their brew.
The AeroPress Flow Control Filter Cap makes an espresso-style concentrate that can be used in lattes, cappuccinos, and other espresso based drinks. While it is quite similar to espresso, it is not real espresso.
Specifically in the DE1, water first enters through the inlet in the grouphead manifold into to the top half of the dispersion block, which has been designed in a way such that water first pools in a reservoir before it reaches the exit holes, at which point water should be exiting each hole at equal flow rate. After this, the bottom half attempts to make water flow in a way such that it covers as wide an area as possible when exiting onto the shower screen.
For espresso enthusiasts, there's nothing quite like watching syrupy coffee being pumped out of the machine. As we marvel at the transformation of our morning coffee into a cup of perfection, it's easy to forget what goes on behind the scenes. In reality, there's a lot that happens in those few short seconds - from the pressure building up inside the machine to the flow of water. To consistently produce perfect shots, it's crucial to understand the science behind pressure and flow. So, let's take a sip and explore exactly how it all works.
Pressure plays a critical role in achieving optimal espresso extraction. The coffee grind, acting as a barrier, can be fine-tuned. By adjusting the water flow using a pump or piston in pump-driven espresso machines, you can increase or decrease pressure.
The pump in espresso machines delivers a maximum flow of water, referred to as water debit. These machines utilize two pump types, vibration and rotary, which yield flow rates of 8mL/s and 30mL/s, respectively.
The question remains: how is the desired 9 bar pressure achieved for optimal espresso extraction?
The pump will provide maximum flow until the system builds pressure and reaches its maximum pressure. An overpressure valve (OPV) is the mechanism that determines the maximum pressure of a system. By reaching a setpoint of maximum pressure, it will cause any additional flow from the pump to be diverted in order to maintain the desired pressure.
For accurate communication of brew pressure, it is essential to know the pressure sensor's location. On a vibratory espresso machine, the pump pressure gauge may display a reading of 9 bars, even if the pressure at the grouphead is lower. This is due to the gauge's placement between the pump and the OPV.
While rotary pumps are powerful, they can lead to inconsistent espresso texture and flavor due to channel formation caused by rapid pressure ramping when flow rates are too high. To ensure consistency, many espresso machine makers set up a flow jet, a small yet crucial tool that regulates pressure ramping without altering maximum pressure. This is inserted into the hydraulic circuit before the grouphead.
A needle valve functions like an adjustable flow jet. You can choose from pre-infusion at 2mL/s and brew setting at 8mL/s. With modern e61 espresso machines, you can now install a fully dynamic needle valve for unparalleled precision in flow profiling.
It is a common misconception that the pressure applied to the puck remains static. In truth, the pressure is influenced by factors such as grind distribution, espresso viscosity, grind setting, burr geometry, and the specific roast profile and origin of the coffee beans.
At the beginning of a brew when the coffee is at its most soluble, the TDS of the resulting liquid will be very high and output a high pressure. As the solubles of the coffee become depleted, the resulting liquid will oftentimes not flow fast enough to hold the OPV set pressure and the group-pressure reading will begin to fall. Note that on machines which can provide a enough flow, the shot will instead speed up drastically in order to hold pressure. This can often result astringency due to the formation of channels.
The pressure gauge's location is crucial as it reads pressure in relation to significant resistance sources, including the OPV, flow jet, and espresso puck. Bernoulli's law dictates that flow restriction in any part of the circuit will cause decreased static pressure readings due to frictional losses or increased fluid kinetic energy. Therefore, understanding the pressure gauge's installation location is vital when determining the brewing pressure.
On an E61 machine, the pump gauge differs from the grouphead gauge due to the overpressure valve (OPV), needle valve, and espresso puck. Pressure inside an espresso puck is not a static reading; it changes because the opening at the bottom is at atmospheric pressure, requiring a pressure drop from the top to the bottom of the puck.
To create the perfect espresso, it's crucial to comprehend the science of pressure and flow during brewing. Optimal 9-bar pressure and regulated flow rates are essential for extracting the coffee's full flavor and texture. Pump types, valves, and puck resistance synergistically contribute to the creation of that delightful, velvety espresso shot.
By appreciating these intricate processes and understanding the significance of pressure gauge placement, espresso enthusiasts can gain a deeper understanding of the factors that shape their morning cup of perfection. So, as you savor your favorite espresso, remember the delicate balance of science and art that goes into each wonderful sip.
Designed by Clive and manufactured by Quick Mill, the LUCCA M58 is a dual boiler espresso machine with rounded panels, blue gauges, joystick controls, and customizable handmade hardwoods. And now with the included LUCCA Flow Control device, you can customize every shot to perfection.
Home espresso is a big investment. We want to make sure that you are 100% in love with your new setup. You have 30 days to return your machine to us without risk. While we can't pay for the shipping on the way back if you change your mind (we absolutely will if there is a problem), we can make the rest of the process as easy as possible.
The LUCCA M58 is a stainless steel dual boiler, rotary pump, E61 espresso machine with a built-in PID and shot timer that can be direct plumbed or run on its built-in reservoir. Built exclusively for Clive by Quick Mill in Italy and customizable with handmade wood panels. This unit includes the LUCCA Flow Control device pre-installed on the group head, providing an easy way to improve your extraction.
The espresso lover who holds aesthetic and delicious espresso to be of equal importance. With a PID and commercial standard 58mm group head, you can pull shots just how the roaster intended or just as easily go off the reservation and experiment with new recipes. You want every shot to be a ritualistic experience. Grinding, tamping, lifting the M58's polished stainless steel brew lever, watching the espresso drip from its included bottomless portafilter. Plus, you need enough steam power for when your milk-with-a-spot-of-coffee friends are over. With the added LUCCA Flow Control gauge, you'll be able to enhance the quality of your espresso and unlock new flavor profiles.
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