About 5 years ago I started writing stuff on this blog, and in less than a month an invoice will come to renew the domain registration and to pay for another year of hosting, which I will be declining to pay.

The blog has served its purpose, but it no longer has a purpose.

In the 5 years since I began writing I have transitioned from being a heckling coffee hobbyist, to someone who works not in the coffee industry, but in a closely related industry, and with a company for whom coffee is a core focus. In some way, oddly, this blog has helped facilitate that. It gave my loud mouth an undeserved soapbox, it introduced me to a whole world of people, many now friends.

I can’t say that I look back fondly on all that I have written.

As a collective (coffee geeks/specialty industry talking heads / starfuckers and starfuckees) we lend too much credence to unbridled theorists. The positive reinforcement from comments, retweets, attention perpetuates this kind of malignant behaviour. It becomes self-fueling, and unfortunately (or fortunately depending on your point of view) it can be rewarding in a roundabout way.

Thought is cheap though. Developing a compelling, yet ultimately shallow narrative is also cheap, and easy (see most TED talks). Action, work, making something, creating change is much more difficult and often less heralded. I hope to do more of the latter and less of the former.

The eulogy probably deserves a more positive conclusion, so I will leave it to the videos embedded below to elevate the gaiety.



Fergus tells it like it is from David Walsh on Vimeo.

Requiem for Atlanta (VacPot of Glory) from David Walsh on Vimeo.

2009 Irish Barista Championship from David Walsh on Vimeo.


Taste Preference Study Data

I have been remiss at publishing this data in a timely manner.

As promised, for anyone interested the data is available here.

The data was presented in a digested form at the Nordic Barista Cup last year, see here.

The slides from that presentation can be downloaded here – DW-NBC12b.

Thanks again to everyone who participated, and to those who helped.


phase 2


For a little over 2 months participants in this study have been making and rating coffee beverages, measuring TDS and submitting data online. In that time a couple of hundred samples have been collected. Samples are still being submitted, albeit at a much slower rate than in the beginning.

Participation has until now been limited to individuals with access to a coffee refractometer. In a way this is what makes that study so beautiful, my job is merely to compile the data at the end. The collection is self-sufficient, the only exertion is on the part of the particpants.

That said, owners, or frequent users of refractometers are hardly an unbiased group. They are undoubtedly an interesting group, but they may have preconceived ideas based on their familiarity with measuring/tasting based on extraction and strength. With that in mind, I want to introduce the second phase of this research series. Here’s how it will work:

  • Initially 50 participants can take part (on a first come first served basis).
  • Participants will receive via post a sample kit, containing 6 coffee sample tubes, 2 syringes, 6 syringe filters, 1 brew water sample tube, written instructions, and a paper form.
  • Participants will be asked to record ground coffee weight, final beverage weight, and taste score for 6 separate brews within a 7 day period (this will require a scale with a minimum 1gram resolution).
  • A 15ml sample from each brew will have to be prepared (instructions below).
  • Participants will be required enter the recorded values in an online form.
  • Participants will be required to return the 6 coffee samples, and 1 brew water sample to one of 5 measuring locations.
  • Participants will receive the results of their samples after they have been measured.

Based on the success of the initial 50/pilot, this study may be expanded in the future. The incentive for participants here is that they get a chance to get some reference points for extraction using their own equipment. I would therefore encourage participants to use their 6 samples wisely and to vary their grind setting, coffee/water ratio, and/or contact time. In that way the results they receive back will be of more value (it is also of more value to the study to have a wider spread of data).

If you wish to participate please fill in the form below (PLACES NOW FULL).

Note you must own a scale with at least 1g resolution. You must also commit to promptly return sample tubes by post.

I want to thank VST and Marco for their generous support and contributions to this study. I also want to thank James Hoffmann, Ben Kaminsky and Emily Oak who have kindly offered to accept and measure sample tubes returned to them by post. In addition to those three, sample tubes may also be returned to Vince Fedele and to myself.



paper form for research

Big thanks to Jessica McDonald from Square Mile on this.

I popped into the Square Mile Roastery a couple of weeks ago, and they had a clipboard with this sheet on it to record all their brews to enter into the research thing we’re doing. It’s a blindingly obvious (why didn’t I think of that) kind of thing, so very closely based on their design – here is a form for anyone else to use…

(just have to remember to enter the data online later!)



Random Brew Recipe Generator

[random-number from=”30″ to=”100″ format=”%b”]%d grams coffee / kilogram water (approx g/L)[/random-number]
[random-number from=”1″ to=”6″ format=”%f”]%d minutes[/random-number]

This is intended for use with the coffee brewing research study.

It has been kept as simple as possible, just providing a brew ratio/recipe and a contact time (this can be interpretted as total contact time or pour time – it doesn’t really matter). The intention is to facilitate experimental combinations of brew parameters which participants may not normally make.

It is not necessary to use this when performing this study. Participants may submit whatever brew they wish – but the option is there.

Parameters not covered above (eg temperature, turbulence, grind size) can be at participants discretion.

It is up to the participant to scale the brew ratio to their beverage size. (eg 68g/1kg ration = 20.4g/300g).


disseminating coffee research(ing)

The SCAE Gold Cup Research programme, which I have discussed previously, is a timely piece of work, but also a massive pain in the arse. I applaud the SCAE for undertaking this endeavour, as it is an ungainly, painful operation to run. It has been conducted 4 or 5 times at various locations around Europe now, I’ve been involved with 2 of those, and it’s no easy task. You have limited time to dial in, sometimes with unfamiliar equipment. Not to mention the difficulty in deciding on one coffee which should represent all coffee.

The scope of the research is to determine taste preference across 5 different levels of extraction, with strength being constant. That in itself would be good to know. However, it isn’t designed to cover the entire landscape of coffee brewing. It would be utterly impractical to do so, given the limitations of resources and time afforded to the study.

What if there was an easier way?

This kind of study needs several things, first off data, lots of it. The more data acquired the more powerful the results. It needs sensory evaluation of coffee made to a known recipe and of a known strength (extraction can thus be inferred).

There are thousands of users of VST refractometers around the world. Most probably brew coffee everyday. If each of these users submitted only one measurement to this study we would have a significant, useable sample size. If some of these users submitted multiple measurements over the course of a few months, we could have a huge, powerful sample size.

So, here’s what I am proposing. Anybody with a refractometer can (and should) submit data to this study.

Using a simple form, submit the recipe, the TDS/strength, and a score (your evaluation of the brew).

This approach has its pros and cons.

  • It gets around the need to pick one coffee. Now it is every coffee or any coffee.
  • It potentially allows for a much wider coverage of the brewing chart.
  • It could allow for a large number of samples to be acquired in a short amount of time, with minimal effort.
  • There will be inherent variability between users, in how they brew, and how they measure, and how they score. There will inevitably be some bad data. However, given a large enough sample size you would hope this would even out.

I would envisage this running for about 6 months, at which time the data would be published and freely available for anyone to use/analyse.

The following is the suggested protocol (I thank Vince Fedele for his help on this).

  • Measure (by weight) and record your ground coffee and your brew water.
  • Transfer a small sample (4-5g) from the brewed (& filtered) coffee to a cool glass/cup.
  • Draw sample into pipette/syringe, expelling as much air as possible, leaving the tip submerged in remaining sample. Do not measure at this time.
  • Evaluate coffee over your normal range of drinking temperatures, choose score based on scale below.
  • Remove pipette, discard a few drops, then transfer to sample well and measure as normal.

If anyone has thoughts on improving this experimental design please leave a comment below. The basic intention of the steps here is to allow the participant to taste the coffee without being influenced by the measurement. Therefore it is key to try to prevent erroneous readings due to evaporation over time.

The form can be found here (on this blog) – or here standalone.

I suggest iPhone users follow this guide to add a shotcut to their homescreen for frequent use.

The scale used for evaluation is a 9 point hedonic scale similar to this:


the worst of coffee in 2011

Lists are great. There should be more lists. Here’s one with a negative tone:

1. The silent dishonesty of working in coffee. It is hard (and not very smart) to be publicly critical of friends,  clients, business partners etc. There is certainly a void in the world of progressive coffee for criticism. It is all over the wine world for example. Bad vintages happen all the time. Bad coffee crops, or below expectation coffee crops are never publicly acknowledged (not to mention poor roasts or brews). It is not an infrequent occurrence for a coffee to arrive at a roastery past its best, or for it to quickly diminish and remain in circulation for some time. It would be of benefit to the coffee industry for a one or (preferably) more independent, authoritative, honest critics to emerge. That way, great coffee which is still in the minority is recognised and is not lost in the sea of “everything is great, hooray for coffee” which seems to prevail. The same goes for the equipment end of the industry (although that seems to be more readily criticised).

2. Sumatra – I did not have any interesting coffee from Asia in 2011. I have low expectations for 2012. If I was a roaster I wouldn’t bother (hint: you don’t need to have a Sumatran on your books).

3. Manual brewing. To order, single cup brewing is a good thing in a retail setting. I fully accept that. The way it is commonly done is not (if you value a consistently near-optimal brew).

4. Filtration. Paper filters are still the best, despite still requiring a bucket of rinse water and still only delivering an acceptable but sub-optimal cup. My kingdom for a cloth filter that didn’t get stinky! (related: props to Coava for their efforts on this front – certainly in the direction of where we need to be in the future).

5. Grinders. Shit on a stick for a multitude of reasons, too many to enumerate. They will probably not have improved in a year’s time. The best innovation I saw in grinders this year was Mahlkonig’s RFID tag credit system, but purely for commercial reasons.

6. SCAE. It’s going to be a long haul if it is to turn around. It offers next to nothing to members. If it didn’t have rights of access to the WBC it would die. I will wait to see if the new education curriculum redresses some of the shortcomings. Here’s hoping for a new SCAE in 2012.

7. Quality vs Quantity of extraction. Both are important, it’s not one or the other. Let’s not throw the baby out with the bath-water. Get a mojo, read Scott Rao’s book, use your own brain etc.

Is 7 enough?

Happy New Year.


burrs again

Grinding coffee for non-espresso brewing at home is a pain in the tits. Short of finding space and the budget for a shop grinder your choices are limited and there a lots of concessions. When the Mahlkonig Vario arrived it was lauded as a grinder which could deliver a quality filter grind, and an espresso grind and sing and dance and do everything in between. Its performance grinding for brewed coffee left an awful lot to be desired.

For the past few months, however, on a daily basis I have been brewing filter coffee with a Mahlkonig Vario. The results have been excellent. The difference, notably is that the stock ceramic burrs have been replaced by a set of steel burrs designed specifically to produce a coarse grind.

What are the effects of swapping these burrs:

  • The grinder is rendered useless for espresso (one step from touching will produce a gusher).
  • The grind rate is greatly decreased (to about 1g/s at a filter setting – the old burrs do faster than that at an espresso setting).
  • The grinder is louder.
  • The noise coupled with the extended grinding time is a minor annoyance in a domestic setting, and perhaps a major annoyance in a light commercial setting.
  • The uniformity of the grind produced is comparable to some shop grinders.

This result suggests a few theories and questions.

Burr size is not necessarily the major determinant of grind uniformity. Perhaps small burrs are typically not good at filter grinding, because small burrs are typically not designed for filter grinding.

Why can some grinders not grind fine enough for espresso?

Is the speed reduction a factor in the output quality or a symptom? Does it suggest that the burr has to strike the coffee more times to achieve sufficient size reduction. Does this mean that the comminution is less explosive? … more controlled? Is there a relationship between burr size, grind rate and uniformity?

Even though the burrs are dramatically different looking, it is hard to elucidate the aspects of the burr desing responsible for these changes. The breaking teeth are shallower and there are many more of them. The cutting teeth are deeper and present a less angled face (they are closer to being on the radial axis). All edges are noticeably sharper to touch.

In any case, these burrs are not yet widely promoted, but they should be. Those in the business of selling Chemexes, Harios and the like to end users should want to offer these. The Vario is a solid grinder, and can with these make a very competent filter grinder. Even better perhaps would be a grinder using these burrs with fewer of the Vario’s bells and whistles, similar or better build quality and a somewhat lower price.

It would be nice if domestic grinder manufacturers defocused on espresso. Hopefully a critical mass of end users will emerge who understand the requirement for a better quality grind, to whom dusts and shards is unnaceptable. It requires enough users who don’t give a damn about espresso grind to create the market to drive these products.