In my never-ending quest to get just a little more crema out of every shot, I've been experimenting with some advice I received from a barista - allow the puck to warm a bit in the porta filter on the group head prior to pre-infusing and pulling.
I have tried this, and I'm still skeptical - I don't really see a difference in the amount of crema that I get. I've tried a few different beans with this experiment:
While I do get a tad more pressure, I'm not getting any more crema than I usually do. His logic was pretty simple, pre-warming at around the 90 degrees Celsius that the head / portafilter tend to be results in more of the oils in the extraction, hence crema.
I've let it pre-heat for up to a few minutes with no real change in the pulled shot, with and without pre-infusing.
Is this just a tall tale? Am I not letting it get hot enough or for long enough? Is Arabica just too gentle of a bean for this to work? The reason I'm trying to get more crema is for a few new deserts I'd like to make, the coffee is still delicious, I just hoped that the experiment would yield more.
Brewing using a Breville Barista Express (manual mode), if it makes any difference.