Inconsistent shots "back to back" shots- 2nd shot much faster.

Mmkelly789 · 2025-02-27T07:31:54+00:00

Hi all,

Looking for some advice before going down another rabbit hole……

I’ve never really taken notice before, however I’ve noticed that I’m getting inconsistent “back to back” shots on my Bianca V3- I knew there was some difference previously but the more I delve in, the more I’ve noticed how quickly the 2nd shot pulls compared to the first.

I’m using a Niche zero and have low flow activated on the Bianca.

I’m flushing between shots and when I say “back to back” I mean there is a good few minutes before pulling the second shot. The machine is fully warmed up before the first shot.

My puck prep is identical, I think, but was the first variable I thought of to look at. I’ve also swapped the second shot for the first as mentioned on other forums as well as here.

I’ve seen some previous discussions around this area before, but I couldn’t find a definite answer. Any ideas/suggestions are welcomed :)

TTal · 2025-02-27T08:39:12+00:00

I have the same with my Cherub, but I put it down to the water in the heater exchanger getting very hot when idling. So I now flush before my first shot and it’s reduced the variation.

I don’t have PID control though like you do with your Bianca, so unsure if this applies to a dual boiler setup.

I guess the main thing is to isolate whether it’s your machine or grinder.

Mmkelly789 · 2025-02-27T08:44:20+00:00

Tal I still flush between each shot, even if the PID should be reducing the variation (i hope).

Isolation of the variable(s) is exactly my mission- Thank you for the feedback on the Cherub!

Adrianmsmith · 2025-03-01T09:31:22+00:00

mkelly789

I would say

Disable low flow , you dont know what the machine thinks is good pre infusion and if it is a set program.

Are you playing with that paddle thingy at all.

Obviously you cant if you are trying to compare back to back shots.

Find out where you need to be with the paddle to get stock e61 flow then do no touch (ever again!!)

Turn off low flow (im suggesting this is the inconsistent variable) every time someone reinvents the wheel it ends up with more corners on it 💥

Try a few more shots and report back.

What weights are you using in and out and what time

Cuprajake · 2025-03-01T09:34:17+00:00

do 3 shots in a row, any difference

Adrianmsmith · 2025-03-01T10:20:54+00:00

Cuprajake would you expect shot time variations with low start selected.

Did you use that feature or stay “traditional” with yours.

Cuprajake · 2025-03-01T10:26:36+00:00

always used low flow to start, with a fully open paddle,

however i would be using two different grinders and two different shot sytles, mine and the mrs,

im wondering if retained grinds are an issuse from first shot to second which should be gone by the third.

Cuprajake · 2025-03-01T10:28:32+00:00

sorry didnt see the bit about swapping the shots round, rules out grinder then,

i never flushed between shots, not really needed imo, id flush to clean once done.

Mmkelly789 · 2025-03-02T07:23:37+00:00

Thanks both- so i did indeed turn off low flow for my first port of call just after posting this :). That being said, if its programable to a set time., i would assume it “knows” to set a low flow regardless as its delivering the same flow/volume each time, to answer @Adrianmsmith

Paddle has always been fully opened.

I’ve done shots back to back, both with coffee and no portafilter, to see if there is a difference in water volume variance with and without coffee/portafilter.

Volume wise, trying to keep it simple with a 1:2 with 18g in around 25-27 seconds.