What is Flow Profiling?
After falling down the rabbit hole of YouTube, Reddit, and various espresso forums, you may still be confused about flow profiling. More importantly (and rightfully), ask yourself: Do I actually need it? The short answer is yes, you surely do. Because why not? Life is too short not to drink great espresso.
Flow profiling sounds complicated, but here's the good news: It’s not convoluted in the slightest.
If you’ve ever looked at a paddle on top of an espresso machine and thought, What does that even do? You’re not alone. What's that extra gauge for? Which gauge am I supposed to monitor? Why are they giving different readings? Flow profiling might sound like something you’d need an engineering degree to understand, but once you strip away the jargon, it’s a straightforward and powerful way to refine your espresso routine, tinker with different recipes, and experiment with various roast levels and coffee origins.
Let’s explore the basics of flow profiling, how it works, and why it has serious potential to be the secret weapon your espresso routine has been missing.
Pressure vs. Flow: Two Sides of the Same Coin
We often hear about “pressure profiling” and “flow profiling” as if they’re different techniques, but, at their core, they're really two ways of executing the same process.
To keep it simple: pressure and flow are connected, albeit indirectly. Pressure and flow aren’t two different levers you can control independently; they’re fundamentally connected. A formula can sum up the relationship between the two, which is essentially a fluid analogy of Ohm’s Law for electricity:
Flow rate = (ΔPressure / Resistance)
You don’t need to memorize the formula, but it helps lend a basic understanding of what’s percolating in the machine. Here’s the espresso version of the formula:
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Flow rate is how fast liquid espresso comes out of the portafilter. In this case, the volume of espresso per second.
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Pressure is the force generated by your machine’s pump. Delta pressure is the difference between atmospheric pressure (1 bar) and the pressure produced by the machine's pump (usually 9 bar).
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Resistance is your coffee puck. A finer grind or higher dose means more resistance; a coarser grind or lower dose means less.
On a standard espresso machine without a flow control system, the pump will produce a constant water flow rate when no coffee puck is adding resistance. Once we add resistance with coffee, both the flow rate and pressure are entirely dependent on the resistance provided by the puck. This is why grind size is so crucial in brewing consistent espresso, and it also means that once we’ve started the shot, there’s nothing we can do to change the equation.
NOTE: The typical flow rate on most espresso machines is around 250 milliliters in 25 seconds. This flow rate can vary depending on whether your machine has a rotary or vibratory pump; the latter requires resistance to push water through, which is regulated by the expansion valve (OPV).
So, is it Flow Profiling or Pressure Profiling?
This depends on what kind of espresso machine you have. Machines with a flow control device, like those equipped with a paddle (primarily mechanical E61 flow control) or needle valve (La Marzocco GS3 MP), let you control the amount of water flowing to the puck during the shot. When you restrict flow, you also reduce pressure. When you increase flow, pressure increases (assuming the puck stays the same).
This is why, to some extent, “flow profiling” and “pressure profiling” are used interchangeably. They’re just two different ways of engaging with the same process. Adjusting the flow also gives you indirect control over pressure. With flow profiling, you’re no longer just watching the shot; you’re an active participant in impacting your extraction in real time, lending a level of control and experimentation that non-profiling machines cannot offer.
Crucially, adding resistance via the coffee puck creates a pressure differential. As the pressure builds in the group head with added resistance from the espresso puck, the pressure differential lessens between the pump and the group head, which means you do not have direct control over flow at all times. For instance, even if you keep the flow control paddle halfway open for the entire extraction, the brew chamber will eventually get 9-10 bar pressure. The ability to accomplish a specific flow rate at a particular pressure profile requires a machine with a brain (computer) that can alter its pump pressure at any given point during espresso extraction, for example, a machine that has a modified gear pump like the Sanremo YOU.
Why Flow Profiling Matters
Let’s examine a few of the real-world benefits that flow profiling has to offer:
- Pre-Infusion: Flow profiling allows you to create a gentle pre-infusion phase at the beginning of your shot. That means slowly saturating the puck to help reduce channeling, increase extraction consistency, and bring more clarity to your cup.
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Post-Infusion: Controlling the flow lets you smooth out how the puck is being hit as the shot progresses. This can minimize over-extraction and help maintain sweetness and balance in the cup, especially toward the end of a shot. As the puck degrades during the extraction, you can taper down the pressure toward the end of your shot to account for the degradation.
- Tailored Shot Styles: Flow profiling is a favorite tool for dialing in “turbo shots” (shorter, faster shots that are still surprisingly sweet) or low-pressure extractions that favor lighter roasts and subtle flavor notes. It allows for the precision of exploring new flavor profiles.
Is Flow Control Worth It?
Absolutely! If you like tinkering, learning, and dialing in your espresso down to the finest detail, flow profiling gives you a level of control that’s hard to beat. It’s not a magic wand, but it’s an incredible tool for having fun and pulling tasty shots.
Ready to take control of your shots? Check out our flow-control espresso machines and start making each shot uniquely yours. As always, we aim to be your guide in all things espresso; please contact us if you want to discuss flow profiling and how to use it effectively or if you want to chat about coffee.
We're looking forward to talking espresso with you!