Why do my shots pull progressively faster?


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:

-Inconsistent pressure
-Water allocation
-Grinder temperature
-Roast date

There seems to be quite a few variables. Let me know what you think and if you have any espresso machine recommendations.


we’ve got the same thing in our shop, it’s the result of the grinders burrs getting warmer and warmer from the friction created from grinding causing, what i can only assume is, the particle size of your grinds becoming larger, meaning there’s an easier path for the water to flow through!

It’s a wise and potential money saving investment of having a second grinder, reducing the work load on just the one!

hope this helped,


Hi Thomas! :kissing_heart:

I’d credit the problems first to inconsistent pressure and/or the burrs of the grinder heating up. You might want to look into checking the inside of the grinder, cleaning the burrs, and re-calibrating them and see if that changes anything.

If not, then I’d see about looking to getting the espresso machine serviced, but due to the age of the machine and the volume of your shop, a new espresso machine definitely wouldn’t hurt. Besides, if you have all the other variables of water, pressure, and (hopefully) roast accounted for, then any other consistencies will be simple to find and tend to. I’d suggest a Linea PB instead of the classic! You can easily set volumetrics for your standard espresso (is it still Epic?) or go full manual.

Hope that helped a little bit. Hope to see you soon!

  • M

Thanks Nico! That may not be a bad idea at all. I appreciate the help.

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Hi Michelle,

Thanks for the help! Now comes the hard part: convincing a chef that he needs to spend money on coffee equipment.

We actually use Heart’s Stereo Blend for our espresso!

I hope you’re well!


Oh right! I was thinking Stereo but got the name mixed up with 49th’s espresso blend. Hopefully your chef will see the value in upgrading the equipment! Good luck!

@michellerj Inconsistent pressure? How so?

Out of curiosity:

  • Do you store your beans in drums or bags?
  • How often do you clean the grinder?

Hi Tom
the main cause of your problem is in your grinder (heat up!)!
Please check the following:
How many kg of beans did you do with the k30? When over 800kg; please chance the grinder plate (first action)
I guess you did fare over 1500kg (only ceramic plates can do it!)
Then you will have less heat and a much more stable situation (and your boss has only a tiny investment to do!)

Further; before you start to buy a coffee machine the source of your problem needs to be solved; the grinder!