I have a Breville Infuser espresso machine as well as a Breville Smart Grinder Pro. The espresso machine comes with two types of filters (for singles and doubles), and can dispense a pre-programmed volume of water corresponding to a single or double dose through its two front buttons (the machine also allows programming these volumes, if desired.)
Thus there are 4 combinations of coffee I could produce:
- Using a single filter, and dispensing water corresponding to a single dose (~30 ml, as I understand).
- Using a double filter, and dispensing water corresponding to a single dose.
- Using a single filter, and dispensing water corresponding to a double dose (~60 ml, as I understand).
- Using a double filter, and dispensing water corresponding to a double dose.
Are any of these 4 cases not usual or "recommended"? Particularly I never brew the combination corresponding to case 3.
What is the expected flavor profile of the espresso produced in each of these cases (more/less acid, sour, sweet, etc.)?
Which of these could be called a ristretto, normale, or lungo?
What parameters should I aim for in each of these cases, in terms of: mass of grounds in the filter before brewing (in g), shot volume (in ml) or mass (in g) in the cup, and extraction time (in s)? I have heard extraction times should be always 25 s regardless of the coffee dose and the volume of water, so 25 s for all combinations above.
This machine has a pressure gauge, indicating water pressure during extraction. Should I watch for a particular value in this gauge, or ignore it and just watch the extraction time? Currently my procedure for adjusting the grind is to make it coarser when pressure is in the upper 2/3rds of the gauge range, and finer when pressure is in the lower 1/3rd of the gauge range. I do not regularly monitor extraction time for adjusting the grind. Using combination 4, and adjusting the grind such that the pressure gauge stays close to the midpoint, extraction times are in the range of 25-30 s. However, using the same grind settings but dosing enough water for a single (combination 2), extraction times are closer to 15 s. To get closer to 25 s I would have to let the pressure gauge reach values way into the upper range.
In closing: although I enjoy the taste of combination 2, it appears most of the water stays in the coffee puck, and the volume actually dispensed in the cup is very small (about 15-20 ml). Perhaps I should reprogram the water volume to get something closer to, say, 30 ml? Would this help me get an extraction time closer to 25 s for this dose (assuming this is the "ideal" extraction time)?