Hi everyone,

After many years of doing things largely by the seat of my pants I have returned recently to this great forum and revisited my technique.

This has also coincided with my purchasing a Vesuvius and beginning to experiment with pressure profiling. One of the areas I am exploring with the Vesuvius's ability to extract using profiles of variable pressure for defined periods of time is the effect of very long pre-infusion. My most used profile at the moment is effectively giving me very low pressure for the first 16 seconds (2-3 bar), then ramps up to 8 bars for the main extraction phase and heads gently down. All my profiles end with an overly long period of quite low pressure so that I can end the extractions manually when I hit my desired brew ratio which is most often 50%.

I'm able to grind very fine using my HG One with this profile. Dwell time is typically about 22 seconds and my best shots are running about 45-50 seconds until I hit my desired brew ratio of 50% (with 18g in a VST basket). So the pressure profiling enabling this loooong pre-infusion has kind of thrown the traditional 25-27 second extraction out the window for me, and I am not complaining. Shots are tasting great on the whole.

Nevertheless, I have revisited quite a bit of advice given here on dialling in blends, SOs etc. etc. and have what is somewhat embarrassingly a fairly simple question. The received wisdom captured by Jim in his must read Espresso 101 is:

To make an extraction less acidic: Keep dose, grind finer for slower flow (more ristretto)
To make an extraction less bitter: Keep dose, grind coarser for faster flow (more lungo)

It seems to me by his referring to making the shot more ristretto or more lungo that he is implicitly stating that the brew ratio should change. Am I correct on this? If so my take is that if I have the following situation:

18g of ground coffee extracting over 50 seconds (once again, I know this is long by most standards but "normal" in my pressure profiling situation) to give me a 36g normale (e.g. 50% brew ratio) that I find good in terms of intensity of flavour but needs to have the acidity brought down somewhat then I should:

1. Maintain my dose at 18g but grind finer
2. Extract at the same pressure profile, but to a brew ratio that is higher than 50%....say 60%, meaning a 30g beverage weight that would extract (because of the finer grind) at something greater than 50 seconds...perhaps 60 seconds or so.

Is this correct? I believe so but have a doubt because so much of what has been written in terms of dialling in has been predicated on either hitting a desired shot time of 25-27 seconds or cutting off a shot when blonding occurs etc. Neither of those apply to me - I am going by brew ratio instead of blonding and my extraction times are considerably longer owing to my long pre-infusions.

Best,

Dave M

Hi Dave,

Check out these threads on the Vesuvius, if you haven't already. Lots of info in there from current Vesuvius owners. Hopefully, some of them will chime in on your questions. Otherwise, perhaps try contacting some of them directly since there aren't many Vesuvius machines in the wild, and people are still experimenting with its profiling ability.

Also, put "Vesuvius" in the subject line of your thread. That will grab attention from people who know the Vesuvius.
Vesuvius has landed

Vesuvius: shot profiling potentials and pitfalls

Hi what coffee you are using ?

canuckcoffeeguy wrote:Hi Dave,

Also, put "Vesuvius" in the subject line of your thread. That will grab attention from people who know the Vesuvius.
Vesuvius has landed

Vesuvius: shot profiling potentials and pitfalls

Thanks Ryan.....I have read those Vesuvius threads and taken your suggestion and added the V word into this topic title.

Thing is, I think apart from the fact that in my situation a 50 second extraction is "normal", my question would still apply if I was using any kind of espresso machine. I may not have phrased it very well (and I just gave the Vesuvius info as context to explain why I am not fixated on a 25-27 second shot time), but basically all I am trying to confirm is if the guidance for dialling down acidity or bitterness (which involves altering the grind to give a slower or faster flow) is also advising one to alter the brew ratio. Per se, my question has nothing to do with whether I am using a pressure profiling machine, a lever machine or a DB E61.

I just have seen this guidance and "think" it is also saying to go to a higher (to control acidity) or lower (to control bitterness) brew ratio but as that was not said specifically in Jim's espresso 101 I just wanted to make sure.

Mrboots2u wrote:Hi what coffee you are using ?

Hello Martin. I am just coming to the end of my Sweet Maria's New Classic Blend. I know the blend very well and can quite reliably take it to FC+ where I find it ticks most of my boxes.

Having gone to the HG One at about the same time as the Vesuvius I am now going to go back to making my own blends, as the single dose grind regimen of the HG One means I can roast beans separately and combine them at the grind stage. Ergo my interest in being sure I have understood correctly the guidance around acidity/bitterness tweaks and whether these require brew ratio changes or not.

I. You're Over Complicating -- Return to First Principles
Over extracted -> Bitter.
Under extracted -> Sour.

Adjust grind, dose, pressure, flow rate, and/or temp to move the pull in whatever direction is necessary for a balanced extraction.

II. Rookie Mistake
Never cut the shot by weight. Brew ratio is only useful definitionally, to tell you the name of the shot you pulled; or aspirationally, as the goal for pulling a particular type of shot.

Each shot presents a number of variables and contingencies. People with incredibly consistent technique and grinders, e.g., Matt Perger, rely on the volumetric (water volume in) controls of their machines to stop the shot and achieve even greater consistency and "deliciousness" than by using visual cues.

Mere mortals like us should cut at the desired extraction level, as shown by the blond point or the arc of the stream from a spouted pf.

Rich

dave_in_gva wrote:Ergo my interest in being sure I have understood correctly the guidance around acidity/bitterness tweaks and whether these require brew ratio changes or not.

Brew ratio doesn't have anything to do with acidity/bitterness. It's a measure of strength -- i.e., the ratio of coffee to water. Changing the brew ratio will only amplify or mute the level of acidity or bitterness that's in the cup. It won't change the acid/bitter balance.

The acid/bitter balance is determined by the extraction yield. Research has shown that most people prefer an extraction yield in the range of 18% - 22%. Below that range, most people will find the cup sour. Above that range, most people will find the cup bitter. The exact point of balance varies with the coffee and, I would contend, with the taster.

Caveat: If you change the brew ratio without changing other parameters to achieve the same flow rate, you will change the extraction yield. That's the only sense in which brew ratio is related to extraction yield and acid/bitter balance.

Wait... so brew ratio will affect extraction yield...

Lots of things affect extraction yield. On a bad coffee (like a moldy, or grassy, or sharp astringent, burnt tar like batch), that would just amplify that defect right? Even if in theory a higher brew ratio (more lungo) should produce a more bitter or caramel-ly shot, this can sometimes turn out wrong if it ends up accentuating a roast defect...

Would one coffee, brewed with two different pressure profiles, PID temperature settings, brew ratios, and grind size, yet having the same extraction yield taste the same in the cup? Sorry, i'm still new to this refractometer thing

FireBurnDread wrote:Wait... so brew ratio will affect extraction yield...

No. It affects strength. I said that brew ratio can indirectly affect extraction yield if you change it without changing other parameters. For example, start with a given dose, grind and shot time that gives you 20% extraction yield. if you then decrease the dose, which decreases the brew ratio, but you don't grind finer, the shot will run faster. If you cut it at the same time, then the extraction yield probably won't be the same. It's not really the change in the brew ratio that affects the extraction yield. It's the relationship of dose, grind and time (and temperature and pressure, to a lesser extent.)

FireBurnDread wrote: Lots of things affect extraction yield. On a bad coffee (like a moldy, or grassy, or sharp astringent, burnt tar like batch), that would just amplify that defect right? Even if in theory a higher brew ratio (more lungo) should produce a more bitter or caramel-ly shot, this can sometimes turn out wrong if it ends up accentuating a roast defect...

The things you cite don't necessarily affect extraction yield, but they do affect the flavor, which is not the same thing. Typically, a lungo shot is more likely to conceal defects because it's weaker. A lower brew ratio will accentuate defects because of the higher concentration (strength) of the drink.

FireBurnDread wrote:Would one coffee, brewed with two different pressure profiles, PID temperature settings, brew ratios, and grind size, yet having the same extraction yield taste the same in the cup? Sorry, i'm still new to this refractometer thing

The extraction yield could be the same, but the taste probably won't be the same. You're confusing extraction yield with taste. They're not synonymous, and I think this is where people get into confusion and arguments about refractometers and extraction yield.

All the extraction yield tells you is where you stand relative to a preferred range of extraction yield, which research has shown is 18% - 22% for most coffees and most people. That range is where it's most likely that the acid and bitter components of the coffee will be in balance or close to it, which is what most people prefer. In my opinion, there are two reasons people prefer a balanced cup or one that's close to balanced:

1. The acid and bitter tastes can be very unpleasant for most people. Some people are sensitive enough that even a little too much sourness or a little too much bitterness makes the cup taste bad to them.

2. The acid and bitter flavors can be quite prominent when they're out of balance, and they tend to mask more subtle flavors present in the coffee.

For most coffees, once you get the extraction yield into the 18% - 22% range, the cup will be balanced enough for you to have the best chance of tasting the inherent flavors -- i.e., the acid and bitter will get out of the way. But the exact extraction yield that gives you the best flavor could be anywhere in that range, so you have to keep dialing in by taste to find it. Once you do, you can reproduce the cup (or close to it) by shooting for the same extraction yield.

Also note that some coffees balance better below or above the preferred range, so it's not an exact scale.

Further note that different people prefer different levels of strength for a given coffee, so you have to experiment with the brew ratio, too.

Temperature can have a significant effect on flavor, but it usually doesn't impact the extraction yield very much unless you make a really drastic change. In my opinion, this is because different levels of heat pull different compounds out of the coffee or pull them in different ratios, but the impact of temperature on overall extraction yield is small compared to the impact of dose, grind and shot time. The extraction yield measurement won't change much as you change temperature, but it's still important because if the acid/bitter components are out of balance you may not be able to taste the difference from changing temperature.

It seems that pressure profiling does affect extraction yield, but I think we're early in that game and don't have a complete understanding of it.