I’ve seemed to notice a trend recently. My bar is equipped with a K30 Vario and an old Aurelia that probably hasn’t been serviced in a while. We serve heart coffee and have high volume weekends. About 4-5 hours of baring during a busy day, my shots start to pull faster and faster, and I continuously adjust the grind size until I’m under the first increment. This happens during about half of my shifts, which are 8 hours. The shop is only open for 8 hours.
Additional info: The espresso machine has its own external filtered water tank (not sure how large), but I’ve never emptied the tank like I have with the second tank connected to a Fetco machine and water spigot. When empty, it takes all night to refill. We may be looking to replace the Aurelia with a Linea classic, however I’ve heard that they aren’t great for high volume shops.
Some things that I’ve thought it could be related to:
There seems to be quite a few variables. Let me know what you think and if you have any espresso machine recommendations.