Breville Barista Pro - Inconsistent output with a standard process?

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#1: Post by jcmonty »

Hi there,

New to the board here.. I did a few searches, but I could not find much regarding the "issue" I am having with my setup. I apologize for the length, but it's driving me a bit crazy! In sum, I seem to get very different shot weights and times between pulls in my normal process, and I am wondering if it's technique or inherently limitations with my setup.

Espresso Machine: Breville Barista Pro (about 2-3 months old now with a few hundred shots pulled)
Grinder: built-in one on the BBP. Internal Burr Setting at 6 (stock)
Tamper: MATOW Depth set at 7mm

Process: (I generally followed this YT setup as my process to eliminate variables: )
I have been using Revolution Roasters beans consistently for the last few weeks 1-2 weeks old for the bag. Kept in a sealed container

- Run a water shot through the system to warm the group head and PF
- Clear out the grinder to ensure there is no residual ground coffee from the previous day (there usually isn't anything detectable).
- Weigh 18gram (17.99-18.01) of recent beans with a gram scale.
- Grind at setting 5 (sometimes 6). I have a 3D printed attachment as to not lose any grinds
- Level coffee Tamp with the distributor
- Tamp coffee consistently with the depth set at 7mm
- Pull shot and weigh

... At this point is where things get inconsistent. I am aiming for 30-35 seconds and a 2:1 ratio (36 grams). I have manually set the volume in the past on the machine for a few shots that fell in this range I have been logging the the outputs for the past few weeks to see if I can see a pattern. Here are the past handful of shots (all settings, coffee, process the same as above):

Grind setting -- Time ( seconds measured by the built-in timer) -- Weight (g)
6 -- 29 -- 43.6
6 -- 25 -- 36.1
6 -- 27 -- 43.9
6 -- 22 -- 42.8
5 -- 31 -- 34.8
5 -- 31 -- 40.8
5 -- 42 -- 16.3
5 -- 28 -- 34.5
5 -- 26 -- 37.8
5 -- 43 -- 20.0
5 -- 30 -- 31.7

As you can see, it seems that every few shots there is an outlier that almost seems "choked". The examples above are actually fairly more consistent than I have seen in the past few weeks. I am not sure what the issue is with the "outlier" shots, but they seem to be the first real shot of the day - so perhaps the system isn't fully warmed up? I just can't imagine that causing such a disparity.

Besides the outliers, I am not able to get as consistent as I would like in terms of time and weight output. Adjustments to the grind usually seems to be too large of an adjustment either way.

Questions that I have:

1) If I adjust the internal burr setting to a "finer" setting, does that give me a tighter gap between external grind settings? OR does it simply shift the limits one way or the other? Everything I have read about the internal burr adjustment points to adjusting if you are at either extreme on the external grind. I am on the finer end, but I don't ever reach an extreme (i.e. "1").

2) Is this just a limitation of the system as a whole? Primarily a Espresso machine limitation or Grinder limitation? I feel like I should be able to get within 1-2 seconds and 2-3 grams output.

3) For the "choked" shots - what should I look for that could be causing that scenario given that no variables are being changed between shot pulls?

Maybe I am expecting too much with this setup? The shots generally taste good, but I am still hunting for that "great" consistency. I would like to max out my setup and process options prior to investing a lot of $$$ into other equipment. Appreciate any help or insight! Or just tell me I am crazy :)

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#2: Post by baldheadracing »

I can't speak to your issues, but on my friend's 870 - which I struggled with last week :evil: - the only way to get a nice grind distribution was to keep the hopper full. All the time, as in top-up the hopper after every couple shots.

I'm pretty sure that the grinder is the same in your newer model. Tre Spade burrs (or clones) like a constant downwards pressure on the burrs (when turning above hand grinder rpm's).

Also, 18g seems like a lot. I could only get decent headspace with the usual (14g-16g) doses.

Good luck!
What I'm interested in is my worst espresso being fantastic - James Hoffmann

jcmonty (original poster)

#3: Post by jcmonty (original poster) »

Thank you for the feedback. Interesting, at first I did keep beans in the hopper and just ground a specific timed amount (before weighing). I may need to try weighing after pulling it sounds like. I will give that a go as a suggestion.

I went with 18g based on the 2:1 ratio for a double shot. I actually thought 18g was on the low side, but am definitely happy to use less coffee if it works out!

Team HB

#4: Post by Jeff »

Welcome to H-B!

It sounds like you've done a great job controlling what you can with your current gear.

Let me start with some general things before getting into some things I might try.

For me, with several years of experience and a relatively high-end setup, I'm happy to have an output (such as time to weight in cup) within about 10% repeatable. More than 10%, I associate with my technique, but only because I know my gear should be more repeatable than 10% (ore on that later). If, for example, you're stopping the shot by weight and your "normal" time is 30 seconds, hitting 27-33 seconds is probably pretty good.

Timed flow tends to be very inaccurate. The time to fully wet the puck will change with grind, humidity, and probably the phase of the moon. There's a couple seconds of variance right there. The flow rate through the puck is related to the applied pressure, the dose and grind, the kind of coffee and its roast, and how the puck "erodes" (dissolves) with time, as you make espresso. There's probably a few that I've missed as well, but that is a long enough list for me to "ignore" timed dispensing.

Flowmeters aren't a lot better. They have some quirks so that the affordable ones are in the 10-20% accuracy range.

Gravimetric machines or machines that can connect to a scale are the ones that I'd "trust", but they start around $3,000 and go up from there. A $15-class scale under the cup and a finger on the button is pretty much just as effective for a home user.

Where can the variations be coming from?

Coffee -- generally not an issue in the same bag over a couple days, but there is "aging" that goes on that causes the character of the extraction fo change slightly as the bag gets older. There is definitely non-uniformity in coffee, but generally it isn't a big issue shot to shot on the same day.

Grinder -- Changes in grind can definitely impact extraction. As you're single dosing, the weight of beans in the hopper isn't a major factor.

Dose -- If you're weighing the output to within 0.1 g, you're probably as close as anyone can reasonably get. When my scale reads 17.0 g, that is somewhere between 16.95 g and 17.05 g

Prep -- How uniform are the grounds in the basket before you tamp. Not just level, but uniform in density and without any furrows, or internal gaps that could later lead to uneven extraction or channeling. (I had originally blurred this into "tamp")

Tamp -- This is believed to primarily impact wetting of the puck (time taken) and, if not well done, uneven extraction under pressure. If the puck channels, the flow rate will generally increase.

Machine -- Many variables here. Are the internal tubes filled? How evenly does the machine wet the puck? Is the temperature consistent? How repeatable is the pump/OPV combination? How uniform and repeatable is the basket in the way it extracts coffee?

Barista Judgement -- Is that shot blonding now? Now? Shoot, it was then.

One of the biggest differences in moving from an entry-level grinder or machine to a mid-range one should be better repeatability.

Some no-/low-cost ideas:

I didn't see that you were stirring or using WDT on the grinds. I'd suggest any of the very fine (0.4 mm or less), straight tools. I like the LeverCraft one (~$40 delivered), but some acupuncture needles in a cork work very well and are under $10. If you want some links, post back and we can dig some up for you. A funnel that sits on the rim of the basket makes this cleaner. Some funnels are available for under $20, but a cut-down yogurt cup can work as well.This one from Amazon was pointed out to me, though I have not tried it myself.

I'm not a big fan of distributor tools and even less of set-depth tamping for home users. I think you can get great results with careful use of a $25-class, plain tamper. For me, comfort and the ability to feel the edge of the basket when I tamp (to confirm I tamped square to the basket) are more important than worrying about tenths of a mm in diameter.

The square-to-basket tampers are easy to use, but the good ones are expensive (over $150). I have seen a link to a moderately priced, square-to-basket tamper on Amazon. I have not tried this one. The reviews point out that it is not "calibrated" (which I don't think is a big loss) as the spring force is against the basket, as well as it potentially having problems with robustness. I did quite well with a vintage tamper for years and years, a "58", by letting my fingertips on the basket rim reinforce that I was tamping square to the basket. Getting ahead of myself, I'd spend $200 toward a better grinder over a fancy tamper.

If not, then what?

Guessing, based on what I've read of Breville's typical all-in-one grinders, that would be the first thing I'd consider upgrading. From what I've read, the built-in grinders can be a challenge to get to grind fine enough, repeatedly, and with small enough steps to adjust the grind. There are some good, espresso-proven hand grinders that start a bit under $200 and can range up to around $300 or so.

Give a bit of time to try out using a WDT tool, leveling the grounds by hand by "raking" with that tool, a moderately firm, square-to-basket tamp, and cutting the shot either by blonding or weight in the cup. Hopefully that will at least get you reliably tasty espresso without big expenditures.


#5: Post by Mack21 »

I was suffering something similar with my barista pro and found that a bit of WDT helped enormously. The grinder can be limiting so clumping can sometimes lead to inconsistent results

Another thing which helped was to forget about the volumetric single and double shot buttons and just use manual extraction (ie hold the 2 cup button for desired pre-infusion time and then release to start shot, press again to stop). Weigh the output as you go and stop it yourself at 36g.

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#6: Post by baldheadracing »

jcmonty wrote:Thank you for the feedback. Interesting, at first I did keep beans in the hopper and just ground a specific timed amount (before weighing). I may need to try weighing after pulling it sounds like. I will give that a go as a suggestion.

I went with 18g based on the 2:1 ratio for a double shot. I actually thought 18g was on the low side, but am definitely happy to use less coffee if it works out!
I ended up calibrating the single button on the grinder side to 7.5g. Load the portafilter once; get 7.5g; tap to level the grounds a bit. Load the portafilter again to fill up to 15g; tap to level the grounds a bit more, and then Stockfleth's; then tamp. You want to get enough coffee into the basket so the tamper doesn't get hung up on the sides of the basket where the basket's sides starts to narrow. The actual weight of grounds to accomplish this will vary depending on the coffee.

Mind you, now people don't know how to do Stockfleth's, but tapping should be good enough. Also keep in mind that the current standard is to use straight-sided baskets with smaller holes (e.g., VST's, 'precision' baskets, etc.); these types of baskets demand careful prep and a putting-green level bed before tamping. However, the Breville comes with a slope-sided basket with larger holes; so we actually want a bit more coffee in the middle to get a consistent density in the puck (or <gasp> use a convex tamper).

(I didn't use WDT because there's no way my friend would do that regularly. WDT can't hurt.)

All that to say that the grinder's not the best; its main shortcomings are variability in taste (some shots are just going to taste better than others, and most will pale in comparison to a "better" grinder), and needing careful and continual adjustment of grind size as the coffee ages (bigger espresso-centric burrs are more forgiving; needing less adjustment over time to produce an acceptable result).
What I'm interested in is my worst espresso being fantastic - James Hoffmann

jcmonty (original poster)

#7: Post by jcmonty (original poster) »

WDT and Stockfleths.. awesome! Learned some new things to read up on today. Looks like I have some experimentation to try.

I did run another shot today incorporating some of the advice (not WDT or Stockfleths though):

Tapped the PF to try and help distribution
Manual shot pull vs. automatic

Result was fairly tasty 18g in -- 41.8g out -- 28 seconds (includes pre-fusion time). lets see if i can stay consistent!

Ultimately - i do think my journey will end up with getting a better grinder, but I want to exhaust some of these options first. Thank you for all the help!

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#8: Post by baldheadracing »

I should clarify - if you do WDT, then there is no benefit to the double-dosing trick I mentioned.

... and I do recommend that you do WDT. I almost always do it.
What I'm interested in is my worst espresso being fantastic - James Hoffmann

jcmonty (original poster)

#9: Post by jcmonty (original poster) »

I am going to give WDT a go, and see how that works. Seems like the obvious next step. I may get a bottomless PF too to be better able to diagnose the shot pull.

jcmonty (original poster)

#10: Post by jcmonty (original poster) »

Thought I would provide a bit of an update for those curious..

I have added WDT (homemade tool) to my routine. I have also started to pull manual shots vs. the pre-set or custom volumetric setting. These two tweaks have allowed me to control my ratio a lot more closely, though I am still seeing inconsistencies in shot times as I will discuss below. I have also been trying different coffees (mostly because family bought me coffee for my birthday :) ).

The WDT definitely seems to improve the consistency of the grounds before the shot pull. Statistically, I would say it's show more consistent results as well, though that is impacted by the manual shot pull as well.

I experimented with longer pre-infusion vs. the 7 sec pre-programmed , and have settled on 8s to be consistent. Not sure if I saw any benefit from going longer at this point.

The big "inconsistency" that still remains is shot time. For example this morning:

Coffee - Andytown Short Strand (Ethopia & Guat. blend with notes of syrupy sweet, toffee, milk chocolate)
Grinder - stock BBP at 5 internal, 4 external
1st shot - 18.01g in - 36.4g out - 34s - Taste slightly sour, smooth, and a bit lukewarm (not terrible, but not great)
2nd shot - 18.01g in -36.4g out - 47s 1- Stronger, a bit more acidic, hotter (better shot IMO)

(note on the timer - that's from start of pre-infusion. First drip is always later on the second shot as well, but I don't always catch the exact time)
Before the first shot, I pull a blind shot into the cup to warm it. Same cup was used for the second shot and was ~ 5 mins after. Grouphead, PF, were noticeably warmer after the second shot than before the first. This scenario is fairly similar to most mornings - with the first shot being faster by about 8-12 seconds with all other variables the same.

From what I have read about this machine, the PIDs control to a lower temp when there is less pressure on the system (i.e blindshot). There is no real way to "pre-heat" given the way that the thermojet system works. Is what I am experiencing consistent with a machine that's not fully heat-soaked or warmed up? It would be a shame if the 1st shot of the day or upon machine start was always significantly poorer given that I only pull 3-4 shots per day. Any recommendations on how to get things warmer or where else to look?

I am still not thrilled with this grinder. As mentioned, I am single dosing, and when I pull the hopper, I will usually find some loose grinds and a few beans. I am hoping to get a Niche in the coming months (fingers crossed) as my next big move.