My current preferred brew profile is based on how I used to make espresso on my Flair. A slow ramping preinfusion, a low pressure soak for a medium bloom. Then the pressure ramps up until it hits a slow syrupy flow, declining in pressure to hold 1.5g/s. Like a Londinium shot, but set to ease in or move linearly like my push lever would. Shorter soaks allow for higher pressures and less acidity depending on preference. Sometimes a bit of channeling isn't always the enemy of balanced flavor. Soaking seems to reduce channeling and pressure, drawing soluble flavors out and then flushing them into the cup with the high pressure transition. These shots have such nice texture, too.
Having a graph makes dialing in shots trivial, like equalizing a set of headphones. Flow too high? Grind finer. Pressure wobbling or rising too quickly? Coarser. Flavors too sharp? Reduce temps, or increase the yield. Not enough texture? Reduce the yield or change the pressure profile. Not enough fruity flavors? Soak longer. It's not always that simple, but usually it is.
That little dip in the flow that matches the hump implies that I slightly overly compacted my puck with the pressure peak. The bump implies a re-expansion as the pressure declined, leveling to 1.5g/s as intended. I could slow down my ease-in to level this off, or drop my maximum pressure; likewise I could coarsen my grind slightly. These small bumps imply slight channeling, but the result is so good already that I choose to leave it be.
Having a graph makes dialing in shots trivial, like equalizing a set of headphones. Flow too high? Grind finer. Pressure wobbling or rising too quickly? Coarser. Flavors too sharp? Reduce temps, or increase the yield. Not enough texture? Reduce the yield or change the pressure profile. Not enough fruity flavors? Soak longer. It's not always that simple, but usually it is.
That little dip in the flow that matches the hump implies that I slightly overly compacted my puck with the pressure peak. The bump implies a re-expansion as the pressure declined, leveling to 1.5g/s as intended. I could slow down my ease-in to level this off, or drop my maximum pressure; likewise I could coarsen my grind slightly. These small bumps imply slight channeling, but the result is so good already that I choose to leave it be.