Achieving Optimal Brew/Pump Pressure

Beginner and pro baristas share tips and tricks.
Grant

#1: Post by Grant »

I guess I have a couple questions in this area.....

How do you know if your pump pressure during brewing is set too high, and perhaps more importantly or applicably to my situation, too low. Too high I think I am familiar with from my history with Silvia. She was very unforgiving of a poor distribution/tamp, and the higher factory pressure would cause easy channeling etc. I did the copper washer pressure mod to Silvia, so have a little experience in the change to a lower pressure and the results. So, I am guessing that having a bit too high of pressure perhaps is not a taste disaster, as good technique somewhat compensates, and as long as you are high, but "close" it would not throw taste off a huge amount.

But, what happens, or what are the symptoms of too *low* of pressure. Having a (previously owned) Bricoletta now with rotary pump, and reading about input pressure effecting output pressure etc., has me wondering if I should be trying to measure what my pump pressure is, and how to do it (cheaply/easily). Now, my technique has not changed that I am aware of, but the one thing I have noticed with the Bric, is that I almost NEVER get channeling or fast pours....even if I have a noticeable bad tamp (angled etc.) I do not have a bottomless PF, but this is just from watching flow color from the spouts.

I am having some taste issues which I cannot nail down (espresso seems harsh, bitter etc), but I have ran through numerous temperature profiles and tried everything I can think of to no avail...extra long cooling flushes, reducing boiler pressure etc. I was thinking temperature was the problem. The first small amount of espresso from the spouts always seems very dark, not oily...almost cloudy/thick dark and black. This dark espresso has a horrible taste.

So, I started to think about what would happen if the temperature was too low? Is that even possible with a rotary pump machine? It is plumbed in, with pressure regulator set to a static 25psi when the pump is off, and the pressure reg shows the pressure drops to about 16psi when the pump is running (cooling flush - no load).

Any thoughts on this...is there a simple (i.e. cheap) way to measure approximate pump pressure, and would pressure have any relation to the harsh taste issues?

Grant

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malachi

#2: Post by malachi »

Yes there is an easy way - buy a portafilter-fitted pressure gauge (available from most if not all of the vendors who support this site).

That being said, I have some feedback to some of your points and one piece of advice for you overall.

Advice... I really doubt that the flavour problem in your espresso is a result of brew pressure. There are so many factors that are more likely to be problems (the beans, the grinder, barista technique, brew temp, water, dirty machine, etc). I would suggest looking at the other factors first as they are far, far more likely. If you can scientifically eliminate all of them then, yes, you want to consider brew pressure.

Some feedback...

1 - Applying lessons learned from the Silvia to the Bricc is problematic. They are very different machines and you cannot assume that what worked (and didn't) on the Silvia will apply, and cannot assume that results and diagnostics from the Silvia are directly applicable either.

2 - Changes in brew pressure of 0.5BAR are generally considered easy to taste. Some people (myself included) claim that changes as little as 0.1BAR are in fact discernible.

3 - The easiest way to identify problems with your pressure tends to be through mouthfeel rather than flavour.

4 - Without a naked portafilter, you cannot know that you do not have distribution problems, uneven extraction, etc. Believe me, a lot of very confident people (myself included) have learned this the hard way.




Finally... it would be helpful if you could describe the "taste issues" you're experiencing in more detail.
You say it tastes "harsh" and "bitter". Does it also taste thin? Does it taste a bit ashy? Oily? Do you get both bitter and sour notes? Is the "harsh" note a bitter harsh? A metallic harsh? What is the aftertaste like?
What coffee are you using?
"Taste is the only morality." -- John Ruskin

Grant (original poster)

#3: Post by Grant (original poster) »

Wow...quick reply Malachi ....thanks! I'll address what I can now...and have to go home later to re-connect my machine to do some more taste tests to respond to some others. We just had new counters installed, so the machine has been out of action for a week.

Grinder is a doserless Rocky. Burrs are very new and razor sharp - less than 10lbs through the burrs. Grinder is cleaned regularly and there is little residual inside. Same beans/grinder makes incredible shots on the Silvia (but Silvia has not been used in a month or so and has been sold, so I can't go back to do some comparisons). Even my wife (who has lousy taste buds) has noticed the drop in quality from Silvia to the Bricoletta.

Bricoletta is spotless clean. I have done numerous thorough cleanings, detergent backflushes and clean water flushes. I have tasted the water running through the machine numerous times, and it tastes good, clean.

Water entering the Bric is softened and filtered through a 20 micron carbon filter. Again, have tasted it and is clean and crisp.

Beans are fresh roasted, I have my own roasted with my i-Roast (medium milk chocolate in color, just into 2nd crack), and also purchased some other from a local roaster (his are much darker and oilier). Actually this is interesting because out of frustration, I even picked up some starbucks espresso beans to try, and while the crema was no where near as thick or dark or plentiful (actually, it was very pale and thin), the "harsh" tastes I will expand upon later when I do some more taste tests were greatly diminished. i.e. I am perhaps overextracting somehow from the fresh beans, but the older, weaker starbucks beans to a lesser degree if that makes any sense.

Last night, I did a roast of "Espresso Choco" beans from the Green Beanery where I get my beans from....here is their description...."You'll do a double take on this rich blend of superb beans from Yemen and Guatemala, added to a quality Brazilian base. No, we haven't added Lady Godiva chocolate to the brew, just the best beans going. Roasting recommendation : Avoid very dark roasts, to maintain the nuance in this blend."

These have always made a great espresso on the Silvia I have been unable to reproduce on the Bricoletta. I will try some again tonight to taste test.

I have tried various lengths of cooling flushes to try the coffee over a range of temperature settings. Nothing seems to help in the temperature department, so while I am thinking this is not a temperature problem, I may be totally out of whack. I have reduced my boiler temp to bounce between about .95 - 1.15 or so. as I was getting a huge amount of hissing and steaming during cooling flushes (7-8oz's needed). After about 4oz now it settles down at the lower boiler pressure.

I think I will try to convert my single PF to a bottomless and see what I can see from there. I am pretty handy with a dremel, so that should keep my costs down in that department.

In general taste summary, I want to say that the taste seems to have an acrid, combination sour and bitterness. Just horrible tasting. Not really burnt, but I guess the term "ashy" you used might be a good description. Even in milk, the "harshness" still comes through. I will post back more taste notes later.

Grant

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malachi

#4: Post by malachi »

I'm going out on a limb here, but my first guess is going to be that this is caused by a combination of brew temp and barista technique.

Some suggestions:

1 - in order to give us a chance to better diagnose the problems, it would be really helpful if you could get a little bit of a commercial blend that we're familiar with. I know it's going to be a pain, but this would eliminate one chunk of guesswork on our part. Maybe Brad from Wicked in Vancouver could set you up with a little Black Cat? If you were able to work with a coffee we've all used, we can not only eliminate this guesswork but give you practical advice for that blend.

2 - if you'd be willing to try the "flush and go" technique to see what the taste result would be, that would really help. I'd suggest, given your machine, that you try building your shot and once tamped etc do as follows: flush until water stops sputtering, count "5 mississippi" (don't rush it), insert portafilter, immediately extract. Taste and record. Repeat with a "4 mississippi" and a "6 mississippi" and then let us know what you get from all of these.

3 - it would also be great if you could describe your shot pulling methodology (sequence of events, measurements including time and volume, etc.).


The naked portafilter conversion is going to be really helpful for diagnosing issues with technique. Let us know what you get.

Finally... I know some people here (Dan) think I'm crazy, but I don't like the stock Bricoletta portafilters at all. If you can source a Marzocco portafilter it is worth doing. I doubt this is in any way related to your issues - but it's something I consider worthwhile in any event.
"Taste is the only morality." -- John Ruskin

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HB
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#5: Post by HB »

malachi wrote:Finally... I know some people here (Dan) think I'm crazy, but I don't like the stock Bricoletta portafilters at all.
To put some context around Chris' comment from Pro's Perspective:
The stock basket is fine, but there may be something not right about the stock portafilter. Now, to be fair, I cannot guarantee that most people would care or even notice the difference. And without testing a few other Bricoletta portafilters, it's not clear if this is a design issue or just something about this particular portafilter.
As an editor, I felt his original text about the portafilter speaking to him at night would introduce credibility issues. The paragraph above was our compromise. OK, joking aside... can I assume chopping the stock Bricoletta portafilter to bottomless would excise the demons reported above? Or is the stock basket also suspect?
Dan Kehn

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malachi

#6: Post by malachi »

basket is totally fine (tested it in other portafilters).
"Taste is the only morality." -- John Ruskin

Grant (original poster)

#7: Post by Grant (original poster) »

malachi wrote:I'm going out on a limb here, but my first guess is going to be that this is caused by a combination of brew temp and barista technique.
Stretching it a bit classing me as a barista....but thanks.
malachi wrote:Some suggestions:

1 - in order to give us a chance to better diagnose the problems, it would be really helpful if you could get a little bit of a commercial blend that we're familiar with. I know it's going to be a pain, but this would eliminate one chunk of guesswork on our part. Maybe Brad from Wicked in Vancouver could set you up with a little Black Cat? If you were able to work with a coffee we've all used, we can not only eliminate this guesswork but give you practical advice for that blend.
I'll see what I can do here...I will see if I can figure out how to get in touch with Brad. Anyone have an e-mail address?
malachi wrote:2 - if you'd be willing to try the "flush and go" technique to see what the taste result would be, that would really help. I'd suggest, given your machine, that you try building your shot and once tamped etc do as follows: flush until water stops sputtering, count "5 mississippi" (don't rush it), insert portafilter, immediately extract. Taste and record. Repeat with a "4 mississippi" and a "6 mississippi" and then let us know what you get from all of these.
This is the technique I use now....I will document some exact wait times and taste results. I read the Bricoletta review on site here about a dozen times before I made the purchase, and I believe that was the recommended.
malachi wrote:3 - it would also be great if you could describe your shot pulling methodology (sequence of events, measurements including time and volume, etc.).
Easy to describe....I do the exact same every time.

- Grab one level "scoop" of beans from container (works out to roughly 17g) and dump into Rocky.
- Remove PF from machine and dry basket with towel.
- Grind 1/2 the beans into basket/PF, distribute around a bit, grind remainder of beans in basket/PF including using air tight lid on the Rocky to push through any residual grounds (so there are a minimal amount in there for next time).
- Distribute evenly in basket and level off, and then apply 1 solid/even tamp (Reg Barber 58mm flat bottom steel tamper) to 30lbs (or so) - damn digital bathroom scale.
- Push cooling flush programmed button (about 4.5 oz right now I think)
- Blow/brush remainder of grinds from lip of basket - I usually don't worry about the few loose grounds on inside edge of basket.
- Insert PF, and push "double" button - programmed to extract 2oz including crema. This would be about 4 seconds or so after previous step.
- Watch for color and volume out of spouts, but if I do not interrupt it early, the controller stops at 2oz.
malachi wrote:The naked portafilter conversion is going to be really helpful for diagnosing issues with technique. Let us know what you get.

Finally... I know some people here (Dan) think I'm crazy, but I don't like the stock Bricoletta portafilters at all. If you can source a Marzocco portafilter it is worth doing. I doubt this is in any way related to your issues - but it's something I consider worthwhile in any event.
Like I believe is mentioned, I think I will try a bottomless first, which should eliminate any issue with PF I hope, and I can do it myself for free. I never use the single spout anyways except to house my blind basket for cleaning.

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malachi

#8: Post by malachi »

OK
I was not aware you were using an auto version of the machine. More clarity here now...

Two things.

1 - flushing by volume is less effective than flushing by time. If you could do me a favor.... after the machine has sat idle, hit flush and time from the end of the water sputtering. Note that time. Repeat when you've pulled a shot or two. Let us know what those two times are. From the time and your boiler pressure setting, we can probably make a reasonable guess on brew temp.

2 - your 2oz extraction... what is the total extraction time on those shots?


I'm going to predict that you're going to see some issues when you use the naked portafilter. You'll probably be able to remedy these by switching from grinding by weight to dosing by volume and by working on distribution. Speaking of which... how do you distribute? Are you using a technique like the Schomer quadrant distribution or the Stockfleths Move or are you doing something less regimented? Also, you'll probably want to experiment with a two-stage tamp (light tamp to preserve distribution, hard tamp with no-weight polish to finish).
"Taste is the only morality." -- John Ruskin

Grant (original poster)

#9: Post by Grant (original poster) »

First off Malachi....thanks for taking the time to work with me on this....I really appreciate your time and expertise in this.
malachi wrote:OK
I was not aware you were using an auto version of the machine. More clarity here now...

Two things.

1 - flushing by volume is less effective than flushing by time. If you could do me a favor.... after the machine has sat idle, hit flush and time from the end of the water sputtering. Note that time. Repeat when you've pulled a shot or two. Let us know what those two times are. From the time and your boiler pressure setting, we can probably make a reasonable guess on brew temp.
I am not completely sure what you mean here. I have programmed my flush volume to end just as the sputtering stops after a long idle time at my current boiler pressure setting - it is currently progammed to flush about 4.5 oz. I have tried lower boiler settings, and then I would also just re-program the button to flush less (for example).

So is what you are asking is for me to do the following?:

- Let machine idle for some time....(let's say 20 minutes)
- Prepare the shot and hit flush button.
- Time from end of water sputtering until flush stops (but this will be zero as I have programmed the button to end right when sputtering stops).
- Prepare another shot, and then when ready hit the flush button.
- Since Hx will not be as overheated as before, the flush will be longer than needed, so record the time from when sputtering stops until flush ends?
- Repeat a couple times and document?

So, is what you are after the time that a programmed flush (in this case, 4.5oz or so), extends past the point where the sputtering stops? Or did I totally not understand your note?

What happened last night after getting things set up again (with my 30 hour old beans), was prepare my shot (machine had idled for a long time), hit the flush button (water dance just settles as the flush ends), counted "5 mississippi", and then pulled my shot. The shot was quite good actually, for the first time in a long time....not great, but good. I still have had better on my Silvia. But lots of rich thick crema and was quite drinkable. No "harsh" or acrid tones that have been common. But a short time later (about 2-3 minutes) I pulled another double to make my wife a cappa, and the horrible taste was back. That time, I manually flushed using the "*" button until the sputtering just stopped, counted "5 missisippi" and then pulled. Shot "looked" OK by appearance, but taste was very off.
malachi wrote:2 - your 2oz extraction... what is the total extraction time on those shots?
With my Rocky set to about "8 clicks" above the burr touching point, the 2 oz shot comes out at about 20-25 seconds. If I move my grinder up one notch, it decreases to about 15 seconds or even less if i keep my tamp constant. One tighter on the grinder, and it stalls if I keep my tamp constant. (Yeah I know...time to upgrade grinders for more control).
malachi wrote:I'm going to predict that you're going to see some issues when you use the naked portafilter. You'll probably be able to remedy these by switching from grinding by weight to dosing by volume and by working on distribution. Speaking of which... how do you distribute? Are you using a technique like the Schomer quadrant distribution or the Stockfleths Move or are you doing something less regimented? Also, you'll probably want to experiment with a two-stage tamp (light tamp to preserve distribution, hard tamp with no-weight polish to finish).
My son is a real video hound, so I will get him to record some of my shots, and I will post them to my WEB server so you can watch the results. I hope to convert the single spout PF to bottomless this weekend.

I am using a slightly less regimented routine, but more a combination of both I think. I push grinds into the emptier areas near the edges...roughly quadrant based, and then use a circular levelling. I will try some two level tamping as well and see what difference it makes.

Grant

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malachi

#10: Post by malachi »

OK.

You need to flush longer.
If you're only flushing until the water stops sputtering, you're probably brewing at a very high temp. The sputtering is from water at or above boiling temp.

Example...

On the Bricc as I had it set up (1.1BAR) - if I were to flush for a full "5 mississippi" count after the water stopped sputtering, I would be at a brew temp of 200F. In general, almost all espressos are best brewed somewhere between 196F and 203F. Based on what you've said, I would guess that your brew temp is in the 205F-208F range.

In other words... you don't flush until the water stops sputtering, stop the flush and then count "5 mississippi" but rather flush for a "5 mississippi" count after the water stops sputtering.

Does that make sense?
"Taste is the only morality." -- John Ruskin