@JHCCoffee
mate there are some old videos from John explaining profiles and what you need depending on what beans you use.
In big lines for developed beans medium to dark, you want a tighter ratio, a super low flow (1-1.5g/s out max) and a long time. Like 20g in-30g out in 40-50sec with a 15-20 sec pi.
For super light roasts- filter roasts-modern-nordic style-tart-acidic-sour roasts you want the opposite. High flow 2-5g/s out in a super short time 15-25 sec max and a bit longer ratio. like 20g in-40/50g out.
Beside that the temp will be a bit different - take into account a coffee puck loses more temp in a slow flow 50 sec shot vs a 20 sec shot with a lot more hot water pumped into the puck to keep it heated. So the theory that light roasts need always super high temps is not always true, it depends on the water you pump at what flow as the water will give heat to the puck. Water can’t exchange heat fast with a low flow.
Beside temp, the pressure is also important, in a test made by the decent community it was shown the extraction goes up on that machine at lower pressures. My point as you can see is that if you know what works for med to dark roasts the opposite will work on light roasts, and if you didnt know Jake is a fan of light roasts.
low flow/high pressure/tight ratio= end up to low extractions, something you want on more developed beans to pull out the caramels/sweetness and less of the roasty notes.
high ratio/high flow/low pressure= more extraction, this is desired for light roasts or else you drink acidic sour shots.
There is nothing special in all this, has been already discussed and presented a lot on many youtube channels or even on discord. Have fun.
