La Marzocco Linea Mini changed from 0.8mm to 0.6mm ruby, with 6 bars pressure

#1: Post by **Jacksen** » November 10th, 2017, 3:24 am

Hi , i have read a couple of threads in this forum and read strive for tone articles regarding low pressure and low water debit. However i am a relatively amateur home barista and need help extraction the best flavors of coffee possible. So far after dialing down to 6 bars, the taste has declined in comparison with ( 9 bars, 0.6mm pulling for 33s ). My question is , for those who have played with 6 bars 0.6mm what is your usual brewing ratio and time? To get my 1:2 ratio i am pulling close to 45-48 seconds... with the coffee only starting to drip at 10s. My current water debit is 240ml/30s. i still get underextracted ,slight sour coffee at this timing . I dose 18 grams,10kg Eazytamp pressure+ mythos one grinder. Should i raise the pressure to get 250ml/30s? Also,do we essentially get better flavors running on 6 bars , or do we drop to 6 bars so that we can get the flow rate as close to 250ml/30s?
On another notes, my espresso has good crema and tiger stripping but it has some bubbles( IS this due to the water i am using?)
Thank you in advance for the responses.

#2: Post by **chris_n** » November 10th, 2017, 4:17 am

there really isn't a one-size-fits-all formula for making good espresso. what tastes great at 6bar to someone else (with their choice of coffee, grinder, water) might not taste so great to someone else. etc

the numbers you are listing sound within the ballpark of what i consider to be good tasting espresso, so maybe it comes down to a matter of preference.

edit: i just saw your equipment list. you're using a great grinder that is more than capable of ideal extractions within the numbers you are providing. lastly, what coffee are you using?

if you find that you're enjoying the coffee more at 9 bar, perhaps that is where you should be at for the type of flavors you're after!

#3: Post by **Peppersass** » November 10th, 2017, 3:01 pm

I agree. Not sure where the idea for using 6 BAR came from, but from what I've read that pressure is too low for a proper espresso extraction. I've seen some posts from people who felt 7 BAR was an improvement, but my recollection is that they eventually concluded that their early impression wasn't correct.

I can see experimenting with 8 BAR, but for a constant pressure machine, I wouldn't go lower than that (machines capable of pressure and/or flow profiling are a different matter.) And if 9 BAR tastes good, go with that.

Also, if you haven't measured actual pressure at the group, say with a Scace device, then what your machine's gauge says is 6 BAR could be much lower.

#4: Post by **nuketopia** » November 10th, 2017, 6:58 pm

I will virtually guarantee if the brew pressure gauge reads 6 bar, it is way, way less at the brew head. The only way to set the pressure correctly is with a SCACE fitted. The brew gauge reads pressure at the 4-way cross fitting that leads to the brew boiler. This is the pressure present before the pressure drop created across whatever jet you have fitted in the brew boiler.

I have a SCACE and 0.6mm jet. I experimented with the lower pressure, but I returned to standard 9 bar pressure.

#5: Post by **Simon345** » November 10th, 2017, 7:17 pm

My lmlm is set up with standard hardware and 6 bar at the onboard manometer. At 9 bar I found the machine too fussy with basket prep and would see visible channeling too often on a naked pf. At 6 bar I virtually never see channeling and my shots taste overall better. I get great flavour and great crema. I will never go back to 9 bar on this machine.

#6: Post by **RyanJE** » November 10th, 2017, 7:58 pm

nuketopia wrote:I will virtually guarantee if the brew pressure gauge reads 6 bar, it is way, way less at the brew head. The only way to set the pressure correctly is with a SCACE fitted. The brew gauge reads pressure at the 4-way cross fitting that leads to the brew boiler. This is the pressure present before the pressure drop created across whatever jet you have fitted in the brew boiler.

I have a SCACE and 0.6mm jet. I experimented with the lower pressure, but I returned to standard 9 bar pressure.

How come you think that about the pressure? If you look at Dans scace testing the machine gauge seems to match the scace gauge?
http://www.youtube.com/watch?v=XB7_vApkX9k

#7: Post by **toto_** » November 10th, 2017, 8:14 pm

RyanJE wrote:How come you think that about the pressure? If you look at Dans scace testing the machine gauge seems to match the scace gauge?
http://www.youtube.com/watch?v=XB7_vApkX9k

The gauge reading is correct and calibrated for the 0.8mm gicleur. When switching to a 0.6mm gicleur the pressure is going to be slightly different.

#8: Post by **nuketopia** » November 12th, 2017, 12:13 am

I know because I have a SCACE-II and have measured it myself.

The machine gauge does not accurately reflect brew pressure (as measured with the SCACE-II) with either the 0.8 nor the 0.6mm orifice.

#9: Post by F1 » November 12th, 2017, 1:23 am

toto_ wrote:The gauge reading is correct and calibrated for the 0.8mm gicleur. When switching to a 0.6mm gicleur the pressure is going to be slightly different.

I agree. I have a scace 2 as well. Every machine I have owned(Rocket Giotto V2, Rocket R58, Lucca M58, Profitec 700) has been a near perfect match between my scace reading and the pressure gauge on the machine. Maybe older models or really cheap machines don't give accurate readings. That whole idea that machine mounted gauges are not accurate needs to be revised.

#10: Post by **Simon345** » November 12th, 2017, 4:34 am

My lmlm measured with a scace was within 0.5 bar of the onboard manometer