HRC-E.B. wrote:I drink mainly traditional espresso roasts (Monsoon Medley, Malabar Gold, Redbird Espresso, Lusso Lionshare). I prefer straight shots. Wife prefers Americanos. I make a few cappas per week too. I like my espressos thick and syrupy, and for me a "good shot" is one where the sweetness of the coffee can be enjoyed without obvious defects such as biting citric acidity, sourness, or excessive bitterness or ashy aftertaste.
Would that line pressure preinfusion bring any tangible benefits?
We drink the same stuff you do and we like it the same way. Malabar and Redbird were our house blends for a few years, until we discovered Aldo Nicoletti (a 3rd generation roaster in Brooklyn). We've used his espresso blend for about a year now and are very, very happy with it. My wife even grinds it for drip! We don't want fruit or flowers in our coffee either, so I can't imagine any improvement in the cup from a DB or flow profiling or tighter temp control than I get with Eric's thermometer and a simple, consistent work flow.
On the other hand, preinfusion has really made my shots consistent. Although my previous machine was also plumbed, it was a vibe pump and there was no easy way to preinfuse. But our ECM HX is rotary, so I can now use PI. I grind into a pitcher and shake it all around with my hand over the top, then pour it into my PF. After grooming the puck, I lock the PF into the group and lift the brew lever to PI position - then I take out the milk, pour what I want into the steaming pitcher, and put the milk away. This takes about 30 seconds, so PI is done when I'm ready to lift the lever all the way and steam while the shot's brewing.
The consistency of my shots is amazing now - every drink is the same and every one is delicious. Between PI and my shaking routine, my naked PF is very well behaved too. So I think you'd find clear improvement from preinfusion, but I doubt that a DB would make a meaningful difference to you. That's my 2c!