Newbie Question: Why Adjust Boiler and Brew Pressure?

[mateo]

OK All, Please forgive the newbie question but I hear people talking about adjusting their brew and/or boiler pressure settings.
Can someone please explain why and or when this should be done. Can someone explain the advantages/disadvantages to adjusting either of these settings higher or lower?

I'm a new Anita owner and I haven't messed with Chris' factory settings, but I'm wondering if I should. Is there something I'm missing out on? In other words, could I be pulling a better shot if I adjusted either one of these settings?

[HB]

Is there something I'm missing out on?

No.

See the section entitled What is the "right" boiler pressure setting? in How I Stopped Worrying and Learned to Love HXs. Briefly, the boiler pressure setting is a tradeoff of the desired brew temperature, steam quality, recovery time between shots, flush amount, and flush frequency. I recommend a boiler pressure setting of 1.2 bar for your Anita, measured from the top of the heating cycle.

The brew pressure should have been regulated prior to shipment. You may wish to experiment with it, varying the pressure from 8 bar to 10 bar; I recommend starting with ~8.5 bar. See Andreja Premium & Anita: Adjust brew pressure in Chris' Coffee FAQs for instructions.

[CyclingCraig]

Hey Mateo;

I just received my Anita from Chris' Coffee Yesterday!! My Thread here: http://www.home-barista.com/forum...ng-pics-t2739.html

What is happening when you brew your shot, what is your brew pressure, I think mine shoots up to high?

For me, I grind, tamp, lock and load.

Then when I lift the Lever to brew, Pressure starts around 4 bar then ramps up to 10.1 bar, but my shots are taking less than 25 seconds. I figured with that high a pressure I would be on the long side rather than the short side time wise??

What is your experience so far?

-Craig

[miKe mcKoffee]

Hey Mateo;

I just received my Anita from Chris' Coffee Yesterday!! My Thread here: http://www.home-barista.com/forum...ng-pics-t2739.html

What is happening when you brew your shot, what is your brew pressure, I think mine shoots up to high?

For me, I grind, tamp, lock and load.

Then when I lift the Lever to brew, Pressure starts around 4 bar then ramps up to 10.1 bar, but my shots are taking less than 25 seconds. I figured with that high a pressure I would be on the long side rather than the short side time wise??

What is your experience so far?

-Craig

10.1bar during shot a bit high but still can pull a shot in 25sec range no problem, even totally stall the shot. On my old Silvia was way up 16.5bar no flow (prior to OPV mod) and with grind, dose, distribution, tamp etc. just right could even pull no spray nekkid shots in proper timing. However the shots will be more harsh/metallic than with better shot pressure. That said PF build off the slightest and too high pressure more easily leads to channeling which also leads to faster shot for a given shot volume. Not to mention taste gone south...

[timo888]

I figured with that high a pressure I would be on the long side rather than the short side time wise??

Although excess pressure can reduce or even stall the flow, flow rate is not in a simple inversely proportional relationship to the pressure.

Apart from setting the brew pressure, you optimize flow by changing the things that determine cake porosity:

--dose and headroom
--coarseness|fineness of grind
--preinfusion, or the comparable effect of a flow-restrictor in brew water path, which permits puck to be gradually saturated under lower brew pressure
--weight of tamp

--selecting single or double basket: single basket's smaller effective egress results in a more restricted flow relative to the double basket, although at 58mm diameter you might get channeling which would seem to produce the opposite effect, so the usual advice is to avoid the single basket until you've nailed the double

Freshness and depth of roast are factors that should be considered when you decide on on dose, grind, and tamp.

Regards
Timo

[BradleyB]

No.

See the section entitled What is the "right" boiler pressure setting? in How I Stopped Worrying and Learned to Love HXs. Briefly, the boiler pressure setting is a tradeoff of the desired brew temperature, steam quality, recovery time between shots, flush amount, and flush frequency. I recommend a boiler pressure setting of 1.2 bar for your Anita, measured from the top of the heating cycle.

The brew pressure should have been regulated prior to shipment. You may wish to experiment with it, varying the pressure from 8 bar to 10 bar; I recommend starting with ~8.5 bar. See Andreja Premium & Anita: Adjust brew pressure in Chris' Coffee FAQs for instructions.

I'm trying to sort out the wisdom gleaned here and recommendations from Jason, a tech at Chris's.

When asking him about adjusting brew pressure, Jason recommended leaving it at the shop setting of 10 bar measured with the blank portafilter, to account for the pressure inconsistencies inherent with a vibe pump. Inquiring further, Jason advised that standard behavior ( 2 oz shot) would be to grind fine enough to bring the brew pressure straight up to the max setting and for it to stay there for the duration of the shot.

Here, in a post from Dan regarding setting vibe pump brew pressure, he notes that the OPV setting only comes into play when pulling ristrettos. This caught my attention because following Jason's advice, I have essentially been pulling ristrettos.

So, my question as I pursue decent 2 oz shots on my new Anita, should I be working toward a grinding, dosing, and packing consistency such that the resistance of the puck itself determines the brew pressure more so than the OPV setting? (I've dropped the brew pressure setting to 9 bar, which has improved the depth and body of the ristrettos.)

Regarding boiler pressure, my Anita came set up to peak at 1.1 bar and bottom at .95 bar, which I haven't played with yet. One at a time.

Thanks,

Brad

[cannonfodder]

Yes. If your shot is fast, grind a little finer, or dose a little more volume, or tamp a little harder. Keeping things consistent are one of the keys to good espresso, and the thing that takes the longest to learn.

I would concentrate on getting your dose and tamp consistent, then vary your grind to get the proper extraction time and taste. Once you have the consistency down, then you can play with things like brew pressure, and dose for different blends. Espresso takes time and patience to master so do not get frustrated. It normally takes a new user a month to get decent shots, six months to get consistently good shots and a year to get consistently excellent shots. Practice, practice, practice.

Leave the boiler setting where it is for now. Once you can produce consistent shots, then you can start to think about changing other variables. One thing at a time.

[BradleyB]

Yes. If your shot is fast, grind a little finer, or dose a little more volume, or tamp a little harder. Keeping things consistent are one of the keys to good espresso, and the thing that takes the longest to learn.

Hey, thanks for responding. Just to underline this in my head: Your "yes" is also to say "Yes, the puck resistance and not the OPV setting should be the determinant of peak brew pressure during the shot." Yes? So I should be working toward a grind, dose and tamp that gets me to that golden rule (without blonding) but without the brew pressure maxing out the OPV for the duration of the shot?

Thanks, Brad

[HB]

So I should be working toward a grind, dose and tamp that gets me to that golden rule (without blonding) but without the brew pressure maxing out the OPV for the duration of the shot?

Well, technically it doesn't matter what the OPV is doing for the duration of the shot since it can only determine the maximum pressure. If you want the long answer, see Recommendations for pressure setting on OPV requested.

Regulate the brew pressure against a blind basket to 9 bar. The actual pressure during a shot will be slightly less than the no flow reading, but 9 bar is a good starting point

[BradleyB]

Well, technically it doesn't matter what the OPV is doing for the duration of the shot since it can only determine the maximum pressure. If you want the long answer, see Recommendations for pressure setting on OPV requested.

Regulate the brew pressure against a blind basket to 9 bar. The actual pressure during a shot will be slightly less than the no flow reading, but 9 bar is a good starting point

That link has the detail I was looking for. Thank you, Dan.

[CyclingCraig]

Mateo

I am also a new anita owner, little over a week now.

Like yours my Brew pressure was set at about 10.1 bar and JUST on Wednesday I dropped it to about 9.3 bar. The shot timing seemed about the same to me, but the flavor was better, as well as the consistency of the espresso (Good mouth feel). I think the blonding is happening later now, but I am still having blonding issues, but pulling OK shots.

Now it seems I am having all kinds of channeling issues though?? Also when I pull the PF, the top of the puck doesn't look intact, as in it was disturbed and muddy in spots?

What is the best way to get some feed back, should I video (Only have a crappy point and shoot digital for video) with bottomless PF? or Reg PF? or just maybe pics?

What would really like is someone in my area to taste it, to see if I am close/getting there?

-Craig

[jesawdy]

Craig-

Crappy point and shoot digi = good for video on HB! I think the trick is getting it lit well enough.

Channeling is MOST likely from inconsistency (not the grinder, not brew pressure).... Work work work. Time time time. You get the idea.

Tamp and Dose digest is your friend in the above. Although I think it needs a bit more in the way of contributors (hint to you veterans out there ). I'd like to see some other videos shot to show other techniques. Also, watch the "Art of the Bean" video (in Barista Tips forum), there is a little gem in that video where the guy does a modified Stockfleths, it's slick, fast and seems to help prevent too much updosing (for me at least).

Consider updating your profile to include your nearest metropolis... I hope you can find someone nearby, it will help.

[cannonfodder]

Now it seems I am having all kinds of channeling issues though?? Also when I pull the PF, the top of the puck doesn't look intact, as in it was disturbed and muddy in spots?

That is interesting. I find that a high brew pressure tends to produce more channeling than a lower pressure. You may want to revisit your dosing and tamp technique, that is most likely the culprit.

You could try up dosing a gram or two to see what happens as well. Too much, or too little headspace can cause premature blonding and channeling as well. My machines work best when the puck has a slight imprint of the shower screen on its surface after the shot has finished. If you have no imprint, try up dosing a hair, if you have a heavy imprint and the puck surface is scraped from excessive pressure, then down dose a little. A wet puck is usually too fine a grind or to low a dose, but not necessarily a problem. As long as it tastes good, it is ok.

As to the OPV setting. When I set my vibe pump machine, I go half a bar higher with the blank basket than what I want in the cup. So at 9 bar with a blank, I get around 8.5 bar during the shot. That is a very general guide, different machines have different plumbing and pumps so it will vary, but that is usually very close.

Videos are always a good diagnostic tool. Seeing is much easier than describing.

[CyclingCraig]

OK!! I think I was TOTALLY Over dosing!!

I was probably like 17.5 or 18.5 grams.. I dropped my dosing and things got MUCH better this morning.

Timing was better, as was color and time to blonding.

I am trying to only change one thing at a time, but I think now that I am lowering the dose size I am much better off. Now I can work on my distribution and tamping.

This morning there was NO BITTER or harshness.. Just coffee flavor, but the flavor was a little on the light side. I will continue to work on it.

I am going to try to post a video later with a bottomless PF and maybe you guys could give me some more critiques.

Thanks
-Craig