I have been using the Quick Mill Silvano with the Baratze Sette 270 for three years .I use a bottomless portafilter with an IMS Compatizione basket. I grind 18 g and pour 36 g espresso. Typically, it takes approximately eight seconds for the first drops to appear, and complete the 36 g in 36 to 38 seconds.

Recently I am getting the following results: it takes 15-20 seconds for the first drops to appear and then the 36 g rushes out and about 10 seconds. In the cup results are not great. Adjusting the grind coarser and finer does not let me zero in. I cleaned the Sette 270 so I don't think it's contributing to the problem. Any suggestions?

Your roasts or commercial?

I get home roast samples from friends that behave identically.

Home roast 80 gms with a Fresh Roast 500 to medium darkness. Single origin Costa Rica Leon Cortes Tarrazu, 5-10 days old. I will switch to Guatemala beans and see if it makes a difference.