A good bag of fresh beans will come in a 12oz bag. Freshness is key as beans age very quickly. Age is a major variable. Your taste preference might range from dark roast to light roasts. The lighter the roast the more demanding it becomes on your grinder, in terms of of pulling a great shot. Darker roasts create more oily residue in your grinder.
I like medium roasts with smaller beans.
I weigh my beans in a dish with a performance espresso scale. 18 grams in with almost no headroom in a bottomless portafilter. The “God shot“ should take about 27 seconds with no fines or spritzing with great crema. The fine control of your grinder setting becomes the all important variable in a system of many variables.
Pulling a bad shot and instantly knowing which way to to go with your grinder setting becomes the proven path to espresso happiness…