Tfili wrote:I've been adjusting the water debit / flow rate (without a portafilter in) on my Pro 800, getting better success reducing it from the 80ml/sec I had initially, but very curious what other users have theirs set at?

Thank you!

Have your shots improved with the lower flow rate? I played with the flow adjustment on my Bosco but really didn't notice any change in my shots so I set it back to the factory setting. What boiler pressure do you normally run?

I feel Im missing something... your shots are bitter and you add more time of extraction (by reducing the water flow) ? The solution wont be the opposite?

Regarding temp management I set my unit to 1 bar since I dont steam at sll. Using temp sticker from flair I didnt noticed the temp ramp other users saw

The way I read it, the scope was to lower the temperature of the water (by decreasing the flow rate though the group head).

Dan - thank you for that video, I haven't seen that before, I'm going to play with that.

John - Yes, I think I've improved my shots by lowering the flow rate. Most of the ashy flavors have disappeared. I'm still getting some once and a while still, so I'm trying to figure out why. I have my PID set at 246 which is about .9 boiler pressure.

Felipe - I'm thinking that by slowing down the boiler water (temp set at 246F) to the group, it has more time to cool to target temp (197-200F). At 20ml/sec, the flow rate is still high compared to a pump machine, so extraction time isn't changing that much. I haven't thought about this too much before so I appreciate the comment. I assume though that the group chamber fills and builds pressure within 3-4 seconds, while before at 80ml/sec it happened in about 1 second. I could be very wrong about all of this, I appreciate any feedback.

At this point I don't know what the "factory" setting is as I played around with this before measuring. I would still appreciate any answers to the original question of what other users flow rate is.

I would think that in this case the extraction time is affected only by the preinfusion which is going to happen at a lower pressure. After you lift the lever the flow stops and the remaining of the extraction is performed by the spring tension, correct?

I may play with this, thank you for this thread. My Pro arrived yesterday and I could not avoid to notice that the first shot after warming up is the best one. It happened yesterday, this morning and after lunch.

It may also help in using less water, since we make only single shots. If I reduce the flow rate and reduce the idle time to zero I may get less water in the chamber. Maybe.

My valve at the moment is as I received it.

Moka 1 Cup wrote:I would think that in this case the extraction time is affected only by the preinfusion which is going to happen at a lower pressure. After you lift the lever the flow stops and the remaining of the extraction is performed by the spring tension, correct?

Yes Monte, this sounds correct from my understanding.

Thank you for your photo, it looks near wide open so your flow is probably close to my original 80ml/sec I measured. Thanks!!

You are welcome.
I have yet to try with the screw fully down, I'll try later hoping it is ok to do it.

There are three tests I have just carried out. I pulled the lever down and raised it immediately. No idle time. I collected all the water until last drop.
All three times I used a regolar dose of coffee.


Factory




Halfway down




About one turn from zero

Moka 1 Cup wrote:You are welcome.
I have yet to try with the screw fully down, I'll try later hoping it is ok to do it.

There are three tests I have just carried out. I pulled the lever down and raised it immediately. No idle time. I collected all the water until last drop.
All three times I used a regolar dose of coffee.

Fantastic post, saved me time doing the same thing. Cheers.