Thursday, 28 June 2012

AeroPress, Hario Mini Mill Grinder, and Gold Cup Extraction

At the time of writing this, the most-read post on here is one I wrote quite early in this self-education process. It covered my early attempts to find the best grind setting with my Hario Mini Mill when brewing with the AeroPress.  I think it's a really important combination of brewing equipment, since the AeroPress is touted as such a simple way to get a clean cup without an expensive pouring kettle... and also because low cost hand grinders are possibly the best way to get more people drinking fresh coffee in their own home.
When I wrote my previous post confounding factors got in the way, such as:
  1. my inexperience with the AeroPress
  2. being new to the grinder
  3. having only a basic understanding of brewing (chemistry etc)
  4. and the biggest problem - having no frame of reference other than repetition, trial and error to guide my tasting towards an end result that seemed perhaps acceptable.
So I'm now a little older, and (perhaps) a little wiser in the ways of coffee, and for some time I've had a nagging desire to go back to the AeroPress/hand grinder combo and try again.  Then the other day someone asked my to give them some advice regarding using the AeroPress and a Porlex, which seemed like too good an opportunity to ignore.  I'm also planning to have the AeroPress as a brewing method in my forthcoming cafe, and to help customers learn how to use their own brewer to make tasty coffees back in their own home, with a hand grinder.  So an updated blog post is probably warranted.

VST LAB refractometer

The great thing is that I have a refractometer now, which is a massive help with overcoming problem #4 from above.  I can experiment until I find the grind setting, temperature, steep time, degree of agitation etc etc that gets me into the Gold Cup zone, and from there start refining based on taste.

My starting technique was:
14g coffee
Mini Mill setting of 5 clicks back from the 'fully closed' position
230g water at 80 degrees C
Fill, agitate gently at 30, 60 and 90 secs, then plunge slowly.

My first three attempts... changing grind setting from 5 to 6 and back to 5 again, agitating more, raising water temperature a little... were all under-extracted, coming in at a concentration strength (TDS) of 1.03%, 0.97% and 1.10% (I'm aiming for 1.30% TDS, giving an extraction yield of 19%). This was really surprising as the grind setting is really as fine as you would ever want it for the AeroPress and any finer would just clog the filter.

Perhaps the grind quality from the Hario Mini Mill isn't helping the extraction process take place effectively.

So anyway, I needed to raise the TDS without changing the brewing ratio.

A degree of success
I raised the water temperature to 90C (1 min 20 from boil with the kettle lid opened).
Half fill, swirl.
Fill to 230g.
At 30s sink crust. At 1 min stir left, right, left, right. 1m30s repeat. 2min lid on and plunge. 2m30s done.

The TDS of this brew came in at 1.25%, with an extraction yield of 18.26%. Statistically a good extraction, within the Gold Cup range.
It tasted ok... rounded, balanced, inoffensive and quite enjoyable. But very little in terms of aroma and flavour. I expect more from this fantastic coffee... Nicaragua Finca San Jose... so something is still not right and again I suspect that this grinder is part of the problem.

Perhaps if I grind coarser and increase steep time and agitation further...? But this isn't the direction I particularly want to take as I don't want to turn the AeroPress into primarily an immersion system, which is what would happen if the grinds are so course that there is very little resistance when plunging. Nonetheless, let's try it...

Interlude: Spot the 'deliberate' mistake...
At 7:30am today I tried to make a coffee. In my bleary, tired state this happened. I suspect it's something that most people have done at some point... at least I hope it isn't just me!!

Reaching the limit
Keeping the grind the same (5 on the Mini Mill) I increased temperature to around 95C, just a few moments off the boil.  I extended the steep time to 3:30 minutes, with a further 30 seconds for plunging (total brew time 4 mins).
Well the taste was better. More rounded, more complex, more acidity. Still a little lacking in depth of aroma though.  Damn! TDS = 1.26%, giving an extraction yield of 18.41%.  So close to my target, but I'm amazed that almost doubling the steep time only increased the concentration of the coffee by one hundredth of a percent!
Something else is at play here. It must be.  And when that happens then the first place I always look is Water. I'm using bottled water - Highland Spring. What could there be about this water that might inhibit the extraction process?
Having read the SCAA Water Quality Handbook I have no real issues with any of these figures except one: "Bicarbonate 150mg/L". This is a measure of Total Alkilinity. The SCAA Standards for this are 40mg/L (ideal), with an acceptable range of 10-100mg/L.

Why does this matter? Because the higher levels of alkilinity in the water does two things. First the alkilinity neutralizes the acidity inherent within the coffee, reducing flavours and making it taste 'flat'. Secondly (according to the Handbook) it makes the coffee particles expand more, which slows down the movement of water in the brewing process, increasing the steep time. (This second statement is open to interpretation though. Personally I take it to mean that more time is needed to achieve a target extraction, but I could be wrong.)

So I do believe the Highland Spring water, despite being better for coffee brewing than most bottled waters, is limiting how well I can brew with the AeroPress... or indeed with any brew method.
In a bid to check this I changed to my Mahlkoenig Guatemala grinder and made a brew with the AeroPress, attempting to use a similar size grind. I ended up using a slightly coarser grind, which will have reduced the TDS of the final brew, but the results seemed to confirm my thoughts regarding the water. Using the same method as above, with a total brew time of 4 mins.  TDS came in at 1.18%, giving an extraction yield of 17.23% ... outside the Gold Cup range. It actually tasted better than the Mini Mill brews that WERE in the Gold Cup range, but clearly there is something hindering extraction other than the grinder, grind size, water temperature, and other typical brew parameters... water.

**Update** a few days later I found a water source with an identical TDS and a calcium hardness level of 61mg/L - statistically very good from a hardness persepctive. It has a pH of around 8mg/L... a little too high... and a sodium content of around 11mg/L, almost double the Highland Spring, but close to the SCAA target.  I haven't yet established the alkilinity levels. Anyway, this different water, with the an almost identical TDS but differences in OTHER water characteristics, had a profoundly different effect upon the extraction process. The result was a BIG difference to both the extraction stats and the tastes and flavours.  TDS went up to 1.37%, and extraction yield to 20.04%.  The flavours were more pronounced, which is great, and it was ok to drink. Unfortunately it now tasted slightly over-extracted to me. There were hints of (perhaps) acids that didn't enhance the flavour.  I had now left it to brew for too long!

So I guess here's one way to get a fairly good Gold Cup extraction from the AeroPress using a Mini Mill. I'm sure there are others, and if you find a good approach please let me know :)

Extraction Yield 18.41 %
TDS 1.26 %
Dose Weight 14.0 g
Brew Water Weight 230 g

Coffee Details
Brew Water Start Temp 95°C
Brew Time I think this is a critical factor defined by your water chemistry. See comments below.
Roaster Name
Roast Style
Grinder Hario Mini Mill
Grind Setting 5 Clicks

14g coffee
Minimill setting 5. Quite Fine.
230g Water 95C, just off boil.
Inverted AeroPress.
Insert grinds. Half fill with water. Stir well to ensure pre-infusion. Fill to 230g (to the rim).
Stir left, right, left, right at 30secs, 1min, 2min, 3min. Fit the filter. NB - Steep Time could range anywhere from 1 minute to up to 4 minutes.  I suggest a 2 minute brew time and then a 30 second plunge, and on subsequent brews either increase or decrease the time if it tastes too weak or too strong.  

At the 2012 Nordic Barista Cup event Vince Fedele of VST Inc, who designed and manufacture the VST Coffee Refractometer, made in important announcement regarding coffee brewing using Gold Cup standards. The announcement directly affects brewing with the AeroPress. When you use infusion/immersion brewing methods (as I am using the AeroPress above) and then filter it, part of the coffee liquor is retained in the grinds. This skews how the resulting extraction yield is presented. So what we may have previously thought was an 18.5% extraction is actually over 20%! To compensate for this it is necessary to increase the dose of coffee used in the brewing process. So looking back at the figures in my summary, the theory goes that I should actually have used a dose of 16g rather than 14g if I wanted to achieve an extraction of around 18.5%. That 2g will have a huge impact upon flavour, and it might help explain why throughout all the above brews, none of them tasted any better than merely 'good'.

Monday, 25 June 2012

Coffee prices in the UK

I've read a few blogs, had a few conversations, and caught a few tweets lately that were unconnected but all seemed to stem from to one common concept... the notion of referring to "the UK coffee market" as a discrete, singular entity; something that can be generalised about.  Here's an example relating to a fairly common debate :

My own humble opinion is that the UK public, if I had to generalise, is not convinced that coffee prices are too low or that despite the ongoing economic problems an increase in their daily coffee spending would be an acceptable hit because man, that coffee is just so worth it.  Granted, if you break down the UK into regions then in some areas there is greater understanding of speciality coffee coupled with greater affluence, and the micro-market (of consumers) in those areas would quite probably accept higher coffee prices. I'm talking about areas of London primarily, which over the past 5 years or so has developed a thriving speciality coffee scene. But London is London and nothing more... it is not the entire UK and is certainly not representative of other regions. It is infact the minority.  The majority of the UK coffee market... the "public" if we are generalising... aren't there yet. Very often people who passionately devote their lives to working in speciality coffee lose the ability to see the world from a non-devotee's perspective. 

You cannot just increase price. Whether the price of something rises or falls is due to 'demand and supply'. People often use that phrase but have never had the most important part explained... the equilibrium price. We all know that as the number of people who want to buy a product increases (table 1), the price rises.  Conversely if lots of suppliers enter the high street selling the same thing, then the price will tend to fall (table 2).  If you put the demand curve and the supply curve together then there is a point at which the meet. At that point the demand for the thing being sold (eg speciality coffee) matches the amount available from shops/suppliers, and the result is basically a price at which everyone is happy.

Table 1
Table 3
Table 2

I agree that baristas deserve to be paid more. I also agree that as the quality of coffee increases, and farmers adopt better production methods, this should be reflected in the price they are paid. This in turn does need to be passed on to consumers. But simply increasing price will not work. Before a price increase will be tolerated, much more work is needed to increase public understanding of the distinction between commodity coffee and speciality coffee, and the value of that distinction.  Without this, an increase in price will result in a decrease in demand for speciality coffee. The market will stall, and good shops will not survive because customers will not perceive any reason to pay more what they think is 'just coffee'.

I haven't yet visited Colonna & Smalls in Bath, but it is clear from everything they do that communication is first and foremost. For a classic example see this post from their blog. Their communication is what enables them to distinguish their speciality coffee in the eyes of the public. In turn it will, I have no doubt, allow them to quite rightly charge more for what is a higher quality product. They do not simply increase price. 

The extent to which those in the speciality coffee industry need to invest time and money on effective communication depends upon how mature the market is in the region their business serves. In the part of Scotland where I live the phrases "single origin", "pourover" or "varietal" mean nothing to the coffee drinking public. The perception is that high street chains surely do it better than anyone (even though there isn't one within an hour's drive!), men of a certain age will demand a white coffee & refuse to order a latte because using fancy names makes them uncomfortable, and the average salary is around 40% lower than that of their London counterparts (1).  Things are changing, of course. Scotland is experiencing its own coffee revolution, fueled by entrepreneurial people in the main cities of Edinburgh and Glasgow. But again, Edinburgh is Edinburgh and nothing more. It has its own demographic groups. There is no 'UK' speciality coffee market - just a collection of small and distinct markets that are not yet joined up.  It will take time. Let's not get ahead of ourselves please, and for God's sake let's stop referring to London as the UK.


Tuesday, 12 June 2012

UK Barista Championships - Epilogue (The Finale)

This is the last post of my UK Barista Championships sextilogy.  The main aim of this final post is to summarise some of my key reflections and suggestions as to how the event could be improved from one competitors perspective.  I think it's unlikely that anything will come of it though, for two reasons:
(a) so far the stock response from the UKBC organisers tends to contain the words "we aren't allowed...".  Granted, but progress comes from suggesting change, not from accepting the status quo. If you keep doing what you've always done, you'll keep getting what you always got.  The rest of the world is moving forward. I'd hate to see the UKBC left behind.
(b) there is an enormous feeling of defensiveness amongst the UKBC organisers.  Attempts to question the way things are done or provide constructive input are often taken as just another person being a hater, and therefore ignored.  Perhaps several years of viscious criticism from many quarters has made the organisers cynical. If so, perhaps it's time the attacks stopped and a better dialogue began.  The organisers are volunteers... many people don't seem to take that into account in their criticism... myself included, formerly.  Equally, competitors devote ridiculous amounts of time, effort and money to the competition... much more than many judges give the competitors credit for in their dismissive demeanour.  So everyone would benefit from less criticism and more constructive feedback.

Three Suggestions.

1. Run proper pre-heat sessions, in every region. That doesn't mean simply placing a Verona and a K30 on a table. I'm talking about Competitor Calibration sessions, which pass on much of the same information that I presume is passed on during the Judges Calibration sessions. Done well, these sessions would result in more competitors delivering a set that substantially impresses the judges, because the competitor would understand the judges' expectations. Currently a competitor could deliver a fantastic routine and amazing signature drink, but if it isn't what the judges are looking for it will score low. This is wrong.  Please note I'm also NOT talking about competitors receiving 'coaching' from judges. The distinction between coaching and transparency seems very clear to me.

2. More control of parameters for the competitors. In real life a barista will source the best beans and brew them the best way. The best way changes with each bean, and it is up to the barista to find it. The ability to increase/decrease the dose, control the brew time, adjust the brew temperature, and deliver an espresso beverage that has a certain mass rather than a certain volume, and to use these to help produce an espresso with a specific extraction target (the best way), are all part of a good barista's skillset. Right now we can't use those skills during the UKBC. The tail is wagging the dog in the competition and baristas are forced to find beans, a roast profile, and sub-optimal brewing parameters that will allow them to adhere to competition rules rather than deliver the best possible espresso.
(a) The machine is capable of brewing at whatever temperature we choose, so let us use the machine to its full potential.
(b) Baskets can be switched out. Let us use whichever basket we choose as long as it fits the portafilter.
(c) Keep timing our shots, but use it to measure consistency rather than to stipulate how long that brew time should be.
(d) Ditch the 2oz rule. It was relevant when espresso was all about the Italian way, but which competitors are still usingdark roasted blends containing robusta?  Fully washed, single origin 100% arabica beans that are roasted lighter than traditional Italian methods require completely different extraction parameters to reveal their delicious bounty as espresso. That may be a 2oz shot, it may be a 1oz shot... the volume is irrelevent (within reason). It is optimal taste that matters.

3. Ensure greater consistency in judging.  The current method seems to involve 'cramming' the judges with knowledge, and you only have to look at former competitor scoresheets to see that there is too much inconsistency.  There are those who feel that the judges are not given enough freedom to score how they want to. Personally I feel the opposite is true. I don't want a judge's personal tastes, views, preferences and dislikes, to have any bearing on competitors' scores.  In an ideal world every judge should score exactly the same. That is surely the purpose of the calibration sessions.  As a competitor it is utterly disheartening to know that you might have scored higher if you hadn't had that one particular judge who happens to have a personal grudge against Sumatran beans in every shape and form.  This suggestion could perhaps be achieved by a more rigorous Judges Calibration programme, extending throughout the year rather than with intense workshops shortly before the competition season.


Well that's it. I'm glad to get the UKBC out of my system as it has been part of my life for eight months... which is amazing considering I was only on stage for 15 minutes in this year's competition. Time to step away from it. The World Barista Championships begin in Vienna today and I'll be watching and avidly supporting the UK Champions, Maxwell, Lynsey, James and Havva. GOOD LUCK, TEAM UK!!

Unsung heroes
There are so many people involved in organising the UK Barista Championships and I'm not going to try to give them all the credit they so deserve. But having been a volunteer at this year's events it is clear to me that the guys from San Remo deserve much more accolade than they would ever ask for.  Dave Wilson, Brandon Thurley, Steve Partridge, and of course Terry... they travelled all over the uk to UKBC venues, arriving before anyone else and leaving long after everyone too, setting everything up, carrying the heavy stuff, coordinating competitors backstage, doing their damnedest to give every competitor exactly the same chance. They don't ask for praise, and that is exactly why they deserve it even more.