More than just curious: How does changing a Flow Rate setting in a profile (say the Default profile) affect actual machine operations. Does it actually control the flow rate through a valve, or does it control flow by reducing pressure.

Today, I had a shot using the Default profile which was 18.0 to 36.0 at 13.0 on the Niche Z. Even though I set pre-infusion at 40 seconds, it ran 11 seconds pre-infusion and 12 seconds pour, for a total of 23 seconds. It flowed at 4 ml declining to 2 mil per second, following the flow settings of the Default profile. BAR rose rose gradually to 9 and then held. I had thought that the shot would have run longer, due to the longer pre-infusion setting. Also curious what triggers the shift to Rise and Hold.

Here is a picture of the profile:

I’ll add a Visualizer link in a moment.

https://visualizer.coffee/shots/79be1717-1969-4358-a907-f65dc34e8f70

    JHCCoffee If you look at the left-most step which controls how you want pre-infusion to progress, you have set it to preinfuse at a flow rate of 4ml/s until either it has preinfused for 40 seconds (the limiter on time is set to <40) or the pressure reaches 4 bar (the pressure limiter is set to <4). From your visualiser shot you can see that the latter condition is triggering first and causing preinfusion to end, thereby causing the profile to move to the rise & hold phase.

    If you want to extend preinfusion, select a slower flow rate in the preinfusion phase. The duration of preinfusion is directly related to this rate of flow.

    I’d suggest posting this sort of query on Diaspora as you know that everyone there has a DE1 and is used to working with the same graphs as you are. Depending on who designed the profile you’re currently running, you can often get feedback from them directly. They can tell you exactly how the profile works and the sort of beans/roast level/parameters it works best with. It’s a nice perk of having a DE1.

    Decent DE1 • Mazzer Philos

        JammyDodger

        Most appreciated, @JammyDodger . Your answer is most helpful. Have also just posted on Diaspora as you suggested.

        Any thoughts on the first part of my post:

        How does changing a Flow Rate setting in a profile (say the Default profile) affect actual machine operations. Does it actually control the flow rate through a valve, or does it control flow by reducing pressure.

            JHCCoffee How does changing a Flow Rate setting in a profile (say the Default profile) affect actual machine operations. Does it actually control the flow rate through a valve, or does it control flow by reducing pressure.

            Diaspora’s good eh! As Luca mentioned in his reply to you, you are using a simple pressure-based profile, not a flow-based profile. In a profile that uses pressure as its main parameter you can set target flow (which the DE1 will maintain by varying the stroke rate of the pumps) but the profile won’t use flow as a limiter, it will use pressure. You’re therefore not running a flow-based profile, you’re still pressure profiling. To flow-profile you need to select to use a flow profile, not a basic pressure profile like the one you are currently using.

            Decent DE1 • Mazzer Philos