Can't get espresso ratio - Page 3

Beginner and pro baristas share tips and tricks.
BaristaBro (original poster)

#21: Post by BaristaBro (original poster) »

Allright, it seems to be me... I went to a local roaster, bought a bag of beans roasted July 19th and had them ground yesterday. Went home straight away and tried pulling a shot: same fast flowing espresso. Used 20 gram, to pull 40 ml of espresso in 20 seconds (not 30 s which is what the recipe with the beans suggests). This is comparable to ground beans from own grinder (Rancilio Rocky).

I'm at a loss. Could still be that I need to modify the grinder or work on the OPV of my Silvia (which I doubt considering the coffee I drank from it in the store). So I'm guessing I'm doing something wrong in preparing the puck. Could really use your help and expertise, maybe you can spot my error(s).

So using the ground coffee, I made a shot with 20.1 grams of coffee, resuling in 40 ml of coffee of 44.3 grams. Took another shot with 21.5 grams for 35 ml in 23 seconds with no bolt imprint before, but a caved-in puck after shot So what I'm thinking now is that the bolt maybe creating a channel that ruins the shot. I tried pulling a 14 g shot, but that was done in 9 seconds (41 ml / 39.7 g). Is there anything that can be done against the significant rise of the puck?

Things I could still try:
  • Replace Silvia shower screen (bolt)
  • Fabricate WDT tool using large cork and some needles
  • Silvia OPV correction, but need manometer first
  • Rocky teflon tape modification
  • I never got the Rocky stepless modification, it already seems to be stepless?
I also tried pulling a 22.7 g shot, it took 31 seconds to get 40 ml at 40.7 g: https://drive.google.com/file/d/1F3OQYu ... sp=sharing, do you have any remarks based on this naked PF video? The espresso was kinda bitter, so I expect (also based on what I think is blonding) I took it too far for the duration of the shot.

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Quirquincho

#22: Post by Quirquincho »

Have you tried to recalibrate the grinder already? Rule this out or you will keep going in circles. Being at the nominal "0" setting and having newer burrs does not guarantee that you currently have the range to grind fine enough.

You mentioned earlier that the store where you bought the machine pulled good shots with your Silvia for you. This suggests that the most likely culprit is the grinder. Moreover, even with the OPV set above 9 bars, a capable grinder should be able to grind fine enough to get into the right time range, if not choke the machine. My stock Gaggia Classic Pro likely operated at 12-13 bars before I modified it to 9 bars and I was able to get decent results with it for over a year.

It was a good idea to get your local shop to grind your coffee, but it tells you very little because it is difficult to know if their grind setting is fine enough for your equipment. A setting that works in one machine does not necessarily work for another even with the same coffee and grinder. If you could ask them to grind some coffee again but way way finer than the first time, you might get more info through the comparison.

Regarding technique, keep your dose low enough that the puck does not touch the screen and/or bolt. When coffee comes in contact with the water, the puck will swell. It needs room to expand. Not touching the bolt or screen when you lock in the pf does not guarantee enough space, hence the nickel/coin test.

In terms of tamping, your videos do suggest that perhaps your tamper is a bit on the smaller side, so you get water forming first a donut in the basket. You could try to ameliorate this by using a nutating technique (challenging to do consistently) or (if yo have the patience) moving the tamper close to the edge of the basket and gently retamping around. Best solution is, of course, to use a tamper appropriate for your basket (e.g. Barista Hustle tamper for a VST basket). I might be wrong, but from your videos it looks like you might have a precision basket, which will be much less forgiving to an undersized tamper than the stock basket.

Last but not least, in more than one of your shot videos, you can see water dripping from the side of the portafilter as you pull the shot. It looks like you need to replace your gasket.

DamianWarS
Supporter ♡

#23: Post by DamianWarS »

BaristaBro wrote:2) the bean quality is too low (have bought cheap supermarket stuff to train, not wasting expensive beans through my inexperience)
I'd have to agree with option 2. old coffee needs to go finer and the shot get's worse as it ages. when my coffee get's old it starts to do weird stuff and I can't seem to go fine enough. fresh coffee has Co2 trapped in it and as the water column pushes down on the puck the Co2 pushes up and gives off backpressure (this is what creates crema). if you have depleted Co2 your puck will be less resistant which means you will have less pressure, since pressure is a product of flow * resistance. So you have to grind finer to compensate but it becomes unsustainable as too fine and there is excess channeling which will make the shot unmanageable. if you want to continue using old coffee and are targetting this 2:1 ratio in about 25-30 seconds you need to increase the resistance of the puck or decrease the pressure (and by that I mean reduce the flow). to decrease the pressure during a shot you can turn your steam wand on and it will effectively split the flow which will have a product of reducing the pressure at the group then you might get this goldilocks ratio/time you're targetting. The coffee won't be good and you will have to compromise on the pressure to accomplish the shot but if you're successful you've learnt the relationship of how flow and resistance contribute to pressure and how to manipulate the pressure on your machine which can be useful skills. however, when it comes to espresso stuff like pressure, time, flow, ratio, etc... are all the methods used to accomplish the resulting espresso and they are all flexible so don't look at them as hard rules. the most important rule is does it taste good?

erik82

#24: Post by erik82 »

Try and rule out somethings first before dong everything at the same time. Do you know someone who has a good grinder where you can bring your machine and pull some shots using your own coffee? That's step 1 that you should do to see if the grinder is the main cause of all your problems (I suspect it is). If someone has a Commandante or Kinu handgrinder that's also good as they are very capable of grinding for espresso.

After that you probably need to change the groupgasket Quirquincho that the leaking along the rim of the portafilter isn't a very good sign but even with this you should still be able to make decent coffee with a good grinder.

Looking at the pour your technique is still way off. I just use a small whisk bought from a cookingsupply store and that works just fine. You can use a wooden satéprikker for WDT (don't know the English word but your dutch so easy) which should do a well enough job for now.

Try these steps first and see what happens.

Edit: The video of the shot you placed in the last link looked pretty good in terms of technique but the grinds are just way too coarse. If those grinds where finer you would have had a really nice espresso.

BaristaBro (original poster)

#25: Post by BaristaBro (original poster) »

Hey everyone, thank you for your replies.

So I just had a friend over has been making espressos a lot longer. Het has a Silvia V5 (newly bought at the time) and a Rocky doserless. He points out that he is grinding at grind setting in the 7-8 range and can get a nice 25-30 seconds extraction consistently. We use the same roaster, maybe different beans, but IMO that doesn't explain why a verified grind setting 0 doesn't simply choke the machine.

He brought a naked PF which we used to test the pressure of the machine. It seemed the pressure was way too high (almost no backflow). We noticed the nut holding the OPV was secured really tightly. We released it a bit to see some overflow and used cc/min backflow to determine the right stance for 10 bar overpressure, so 9 bar on PF. However, it doesn't help the extraction time of the espresso. It still flows way too fast.

Could it be that there's something wrong with the OPV? The shop owner who sold the machine told me he cleaned it, replaced the rubber ring and adjusted it to 10 bar as well (which seems questionable with how tight the nut was secured).

Problem now is that with the loose nut there's water dripping. Seems to indicate that that rubber ring is not doing its job either.

What do you think?

erik82

#26: Post by erik82 »

You still need to grind finer. That's the only way to get a slower extraction. Dropping pressure will help once you grind enough but won't do anything if the grind is still too coarse.

A tight nut on the OPV can also just mean loctite. Where's the water dripping as you're talking about the nut of the OPV but refer to the grouphead gasket.

BaristaBro (original poster)

#27: Post by BaristaBro (original poster) »

And I think you and everyone here was right: I need a different grinder.

Today I switched things around and went to my friends home with my grinder. The exact same problem of fast flow happened with his Silvia V5.

We then tried his grinder, interestingly also a Rancilio Rocky (the doserless), and we were able to get a good shot a couple of times: 20 g of ground beans, approximately 40 g of espresso in more or less 30 seconds. Things deviated within ok margins. The taste was rich and the body full, these were good espressos in my book.

I then used his grinder to grind some beans on the same setting, quickly took it home and took a shot. I can get the same ratio of 1:2 in ~30 seconds. However, the body is definitely not so full. Moreover, the taste is a bit more towards the sour side and couldn't find the same finer taste tones (primarily nuts and sweets) I could over at my friend's place. Maybe something indeed is off with the pressure (being too high) or my temperature is lower (too low maybe even), but at least I can now start finetuning rather than debugging.

All in all it's a start. So now I have can plough through HB to find a good step-up in the grinder game. Thanks to everyone that went along on my journey, for your patience and tips & suggestions!

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cafeIKE
Supporter ★

#28: Post by cafeIKE »

reply started before ^^^^^^^^^^^^^^^^ posted
  • until the grinder is calibrated, all bets are off
  • OPV exactitude is nice by not a killer
  • ground coffee is good for 15 minutes
  • pucks are compost and tell very little
  • why all the googHELL image shares instead of native images?
post a picture of the Rocky adjustment mechanism. If you have discrete steps, return the grinder if your can. If you can't, remove the step lock and get a couple piano tuning wedges [or something similar] to lock the grind in place for a quick and dirty stepless mod

Rocky full steps are 10x useless.
Stepless mod for Rancilio Rocky- a cleaner approach from 2008!

Set PID to 95°C until everything else is resolved.

erik82

#29: Post by erik82 »

BaristaBro wrote:I then used his grinder to grind some beans on the same setting, quickly took it home and took a shot. I can get the same ratio of 1:2 in ~30 seconds. However, the body is definitely not so full. Moreover, the taste is a bit more towards the sour side and couldn't find the same finer taste tones (primarily nuts and sweets) I could over at my friend's place. Maybe something indeed is off with the pressure (being too high) or my temperature is lower (too low maybe even), but at least I can now start finetuning rather than debugging.
Pretty normal behaviour for stale grinds which is 5-10min after it's ground. So this doesn't tell you anything about your machine just that your grinder is crap. So now you've found your problem and should get a decent grinder and start over again. At this point there's nothing you can say about how your machine performs unless you take your machine to that friend and do the same again.

Here are some good (Mignon)/great (K10) grinders that you could try:
https://koffiepraat.nl/forum/viewtopic.php?f=14&t=11500
https://koffiepraat.nl/forum/viewtopic.php?f=14&t=11335