Where are we with pressure profiling?

November 14th, 2010

David Schomer’s comments on pressure profiling this week haven’t been particularly well received it seems.

This is quite frustrating – he’s raising an interesting point, but has done so in a way that allows it to be torn apart due to his presentation. You could say he’s unable to back it up, he’s making such sweeping statements topped up with a self confidence easily labelled as arrogance. 1

My experience with pressure profiling is also fairly limited. Back in August ’08 I had a rather wonderful custom built profiler leant to me for a while, incredibly generously I should add, by John Ermacoff (who – despite not being a coffee industry person – has one of the most interesitng flickr accounts ever!).

People who knew about my experiments with that profiler have often asked why I haven’t really posted much about it online. In fact there is very little posted anywhere about pressure profiling, apart from many people being excited about its possibilities and about how various manufacturers are bringing machines to market to fulfill people’s interest.

Tim Wendelboe’s post has probably been my favourite on it, as I identified with a lot of what he said. If you haven’t read it then I’d suggest going there now.

My own experience’s with profiling could easily be summed up with a sentence stolen from that particular post:

It is also very easy to make really bad tasting shots.

Pressure profiling is immensely frustrating. You change a profile and you change the flavour, there is no denying the impact of changing pressure during the shot on the taste in the cup. Please note that this doesn’t mean the cup is improved, only different to before. Most of the time it is worse. What starts to break your head is wondering if it is worse because the profile is wrong, or because you got the dose/grind/brew weight wrong for that particular profile. Extraction analysis would help a little bit, but you’ll get lost incredibly fast.

Dialling in with tasting is also very difficult. Shot variance is often confusing when it comes to trying to diagnose problems via acidity/astringency/body/bitterness/balance/etc, and espresso palate fatigue was a major issue for me. I’d just start to feel like I was making some headway when I would hit the tasting wall.

What is worth noting is that despite the number of machines out there that can now profile to some extent, we still lack a coherence on even the basics of creating a profile for a certain coffee. I’d be willing to guess that most baristas using them are having a similar experience to me. I’d also hazard a guess that those using them in commercial environments (rather than lab/roastery/training room ones) are using very, very simple profiles so that they stand a chance of dialling in and repeating.

La Marzocco Profiling Chart: Interesting to note that the suggested profiles make no correlation with flavour, only suggestions to make notes on flavour - something you could say about varying dose or brew time.

Does this mean I think we should write off pressure profiling? Should it be dismissed in a Schomer-esque sweeping statement?

No. I think there is, somewhere in it, some mileage and benefit. However, to get at it will require a bit of cohesive work from the industry. A little crowdsourcing would be very useful here. I don’t know where would be a good hub, or what format that should be (forum/messageboard etc).

All of this is a long rambling answer to a barely asked question earlier in the post: Why didn’t I post anything about pressure profiling and my experiences with it?

I’ll be honest and admit that having near infinite control over the profile (which John’s machine offered, along with automation too) left me confused and intimidated. I hope that I’ve learned a little about espresso in the last two years (I certainly feel like I have), and I hope that I could now come back to it with a little more structure and forethought when it comes to experiments. However – at the time I felt I had nothing to say. I had found no repeatable trends, I had no theories, I’d played with a bunch of other people’s profiles (Andy Schecter and Greg Scace have both done way more work on this than me – and I was grateful for their input). I am curious whether other people out there are having a similar experience?

If we don’t make some headway, as a group, then we’ll probably end up abandoning it – too much work, too hard to replicate, too difficult to implement into a busy bar – and we might have missed something potentially very useful. So I will end this with a plea to those who are experimenting to share more – even if all they are sharing is a feeling of confusion and frustration – as all stand to benefit from a little shared experience.

  1. What actually annoys me more is the pseudo science is his writing. ” the preservation of these unstable molecular structures that constitute coffee flavor/aroma” being an example. Ah yes – these unnamed, mystery structures of wonder, so unstable that they’ve somehow survived temperatures in excess of 400F during roasting, but still so unstable that 1F variance in water temp ruins all!  I should also add that in person he’s been nothing but friendly to me, so I feel a little mean writing this.  ↩︎

Comment Policy

There are no longer comments on new posts. If you'd like to respond you can find me on twitter.