Questions after my first 10 shots

Beginner and pro baristas share tips and tricks.
dsc106

#1: Post by dsc106 »

Gear: ECM Synch, Niche Zero, Decent 18g basket, Bottomless PF

Technique: Pour from NZ into basket via the Decent funnel (not doing the upside down method to avoid compression). Stir using WDT. Tap on counter to settle grounds. OCD v3 to flatten bed. Tamp via Decent Tamper v3 (auto level, 15psi consistent).

Recipe: Starting off, I have been using Clive's free bag of Verve Bronson and their suggested ristretto starter recipe of 1:1.5 brew ratio - 18g in, 30g out, in 25-30 seconds. I have grind setting around 10-12 on the NZ. PID temp at 201/202.

Questions:

1.) I set my plumbed in machine to 2 bar line pressure input. On my first couple shots, after pulling, I noticed the line pressure creep upwards to 4,5,6 bar! Flushed group head and removed PF, then up and up again! I turned down the pressure regulator. Then, the pressure was too low, so I turned the regulator back up. It seems to be stabilized now. Any idea what was going on with this weird pressure issue?

2.) Where should I be pulling shots pressure wise? After adjusting my machine, when I open brew lever I get 9 bar pressure. But when I grind on NZ at fines setting 11, 18g basket with 18g, I was getting close to 10 bar pressure when pulling a shot. Should I be closer to 9? Should I regulate more pressure at the line?

3.) After pulling some shots and emptying the puck via knockbox, I noticed I get stuck leftover grounds compressed around the edges of the basket. Is this normal, or do I need to work on my technique? My more compression on edge of basket?

4.) Is it ok to use a metal spoon to scrape the PF basket out from the compressed grounds, or will this scratch the PF basket? Also, do I need to be careful not to scratch the basket when using WDT?

5.) I noticed when pulling shots, the bottom of my Acaia Lunar scale gets splashed and wet. Is this ok for the scale?

IntrepidQ3

#2: Post by IntrepidQ3 »

1) I don't have a plumbed machine so I can not comment.

2) 9 Bar is the goal, if it wanders and the shot still tastes good don't worry. At the end of the day it's the taste that should be the goal, not meeting the requirements of the guides (ratios, pressure, pull time, ect.). You'll drive your self mad trying to get these were every suggests and if you do have improvements in taste it will not be enough to make it worth it.

3) Don't concern yourself with this either. If there is a issues with luck prep it will show it self from the naked portafilter.

4) The basket can handle the abuse of a spoon and WTD. The bottom of mine has scratches from WTD. For cleaning though a quick rinse under a faucet will clean anything left over from knocking out the puck. If your not close to a sink, I have seen other have a rinsing container .

5) Yes its ok. Those scales are designed specifically for that type of abuse.

Remember the goal is a tasty shot and not being successful at hitting defined parameters! Those parameters are just guides to get you close to what you like. Every coffee is different and will need to be handled slightly different. I am currently enjoying a brazil from my LCS at 17g in, 26 out in 35 to 38 sec.. none of this is in the golden rules, but it sure wows me! It tastes terrible as a 18g in, 36 out, in 28 sec... :lol:
"As you know, an explorer's temperament requires two basic qualities: optimism in attempt, criticism in work."-Freud

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JohnB.
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#3: Post by JohnB. »

dsc106 wrote:

1.) I set my plumbed in machine to 2 bar line pressure input. On my first couple shots, after pulling, I noticed the line pressure creep upwards to 4,5,6 bar! Flushed group head and removed PF, then up and up again! I turned down the pressure regulator. Then, the pressure was too low, so I turned the regulator back up. It seems to be stabilized now. Any idea what was going on with this weird pressure issue?
Where were you seeing this? On the regulator gauge or the machines brew boiler gauge?
LMWDP 267

Jeff

#4: Post by Jeff »

On (2), extraction pressure, that is driven by the pump, so changing the upstream line pressure shouldn't make a difference. On a rotary pump machine it is typically set at the pump.

9 bar is typical. Some people find the flavor profile of a slightly lower pressure is preferable. Lever machines often run in the 6-8 bar range. Much over 9 bar and you're getting further into the range where the flow through the puck declines with increasing pressure and many consider the espresso to be inferior in flavor.

dsc106

#5: Post by dsc106 »

Sorry, just checked back in here.

When I saw the pressure creeping up it was on the machine itself, going up from 2,3,4,5,6. It was mirroed on the regulator underneath the sink. I have not experienced this again since, I suspect it is the houses line pressure flux and that I first set it up when things were low, and it was peaking too high? I have set it lower and now the pressure regulator @ filter tends to read between 15 psi and 35 psi depending on time of day and conditions. The machine itself tends to hold showing 1-2 bars pressure on the pump when its just sitting there idle.

Is that normal?

Second, regarding the brew pressure when pulling a shot. I wonder if it is my elevation? Clive Coffee benched it in the valley, but I am up in the hills at 700 ft elevation. Perhaps this is why I tend to be @ around 10 bars when I pull shots, just a little less. So, that's 10 bar at the pump, but I am confused by what people mean when they suggest 9 bar. Because 10 bar @ the pump (where the gauge reads) would be perhaps 9 bar at the brew head... right?

So do I want to set the machine so that the gauge reads 9 bar? That would be at the pump, yeah? And equate to perhaps 8 bar at the brew head?

I do wonder if I have been pulling my shots with too much pressure.

dsc106

#6: Post by dsc106 »

I will also add two more little questions, maybe silly:

(A) Is it bad to leave equipment on the warming tray, such as spare portafilters, basket, tamper, etc? It gets hot to the touch and I am just wondering about leaving the stainless steel equipment up there for weeks/months on end with lots of heat during the day.

(B) Should I worry much about scratching the basket during WDT with a sharp tool, or no worries on scratching the basket? I am using a nice Decent Espresso 18g and 20g basket.

DamianWarS

#7: Post by DamianWarS »

dsc106 wrote:2.) Where should I be pulling shots pressure wise? After adjusting my machine, when I open brew lever I get 9 bar pressure. But when I grind on NZ at fines setting 11, 18g basket with 18g, I was getting close to 10 bar pressure when pulling a shot. Should I be closer to 9? Should I regulate more pressure at the line?
the pressure at the pump is different than the pressure at the group. In another post you mentioned that you thought 10 bar at the pump would be about 9 bar at the group and that's probably correct but it's assuming that 9 bar at the group is the best pressure. as water flows through piping with an opening at the end there will be a pressure drop until it reaches atmosphic pressue (0 bar) but things like the coffee bed is not exactly an opening and has impact on the pressure itself. the tighter, finer and more compacted the coffee bed the more resistence it will have and the pressure will go up until it's maxed out based on your machine. At a certain point it actually creates a counter-effect where the greater the pressue the more it compresses the bed and slows the flow not speeds it up as you would think. the ideal pressure is the pressure that allows the fastest flow and incidently in most cases that's about 9 bar at the pump (each machines varies of course) 9 bar at the pump is going to be closer to 8 bar at the group. but every machine isn't the same so it varies and I think a better goal is to not to worry so much about the pressure and worry about what the shot is like. If you want to reduce the pressure using the resistence of coffee alone you'll have to make the coffee bed more permiable which means dosing down or grinding coarser or you can try things like better puck prep. one sort of "hack" way of improving the flow is adding a paper filter to the bottom of the PF under the bed and to the top over the bed (like an aeropress filter) as explained here or here or a HB discussion on it here. The idea is the bottom prevents fines from clogging up the basket holes and the top prevents errsion of the puck together increases the flow as the flow is more consistent. because the flow is increased it means the coffee is more permiable and it may help you find that sweet spot in pressure.