Sunday, 30 October 2011

Messing with the AeroPress (4)

Quick post... I tried Jeff Verellen's AeroPress technique, or at least as best as I could understand it from the description on the WAC website, and my significantly lower skillset than Jeff.
17g grounds
270g water
Threw away the last approx 50g of brew slurry rather than pressing it into the cup - and also lost some in absorbtion.
I suppose I didn't quite follow the recipe, as my brew water began at around 95C rather than 80C.

TDS 1.24%
Extraction Yield: 15.0% (based upon ending up with 205g of coffee in the cup.  But I'm not exactly sure whether I should be using 205g or 270g in the formula, for reasons stated in my previous blog post.

I enjoyed it. It wasn't stunning, but I enjoyed tasting the higher TDS than I've been achieving over the past few days.  A while back there was a brief discussion regarding whether it is possible to taste the level of extraction. I think you can, because there was something lacking from this brew... despite the TDS being 'in the zone'.  It tasted of good coffee, wasn't bitter, had a decent body and mouthfeel, but was just... erm...  'simple'. Not complex. I couldn't pick out much. It didn't linger on the lips - vanishing quickly and leaving nothing to remember I had ever tasted it.

But this was just one attempt, and one attempt isn't enough to judge - it's only enough to record my findings so I have something to compare with upon the next attempt.

Friday, 28 October 2011

Messing with the AeroPress (3)

Before I continue with these AeroPress brews, just a quick comment on the World AeroPress Championships.  I just read the technique devised by this year's winner, Jeff Verellen, here. I love reading the details of how other people conduct manual brewing.  There's a lot of creativity involved in taking something as simple as the AeroPress, or the V60, or the French Press, and making coffee in a way that is somehow different from how others have done it in the past... whilst not tipping over into obviously using a technique for the sheer novelty value.  What I especially like is when the 'rules' are bent or even thrown out completely to produce something that tastes good without disrespecting the work that has gone into bringing the beans to the brewer's possession.  Don't get me wrong... the Brewing Control Chart has vastly improved my understanding of manual brewing and hopefully helped me make better coffee.  However, I've never liked the idea of rules that restrict innovation and experimentation... so I like to think of the charts and established brew targets as guidelines rather than rules.  (But perhaps I can only get away with saying this because I'm not experienced enough to know otherwise!)

So... as the above link shows, Jeff used 17g with 270g of water... a 1 to 15.8 ratio. However, he apparently ditched the last 50g during the downpress... the link refers to that 50g as water, but I presume it is actually the brew slurry.  So that would leave 220g of coffee... perhaps actually more like 205g when you take into account water that is absorbed by the grinds and therefore doesn't pass through to the cup.

I'm intrigued by this.  It reminds me of the way some people describe a ristretto as simply stopping the shot early (which I don't agree with). When you do that with espresso I believe you're going to get a rich shot with a high TDS, but a low extraction yield (I could be wrong... that's just my current understanding). Once again it's the "over-dosed and under-extracted" scenario that annoys Mr Hoffman so much. 

I wonder... does this apply this to Jeff's AeroPress technique?  There is a difference. In an espresso basket I'd imagine the pressure throughout the puck, and the extraction of the grounds, is relatively even (granted the pressure at the top will differ from the pressure at the bottom).  Whereas in the AeroPress the grounds are floating around in the slurry, and only the grounds that are hitting the filter paper are achieving full extraction. The rest of the grinds/solids are still floating around during the downpress.  So if you don't press all the way down, then actually not only are you using only some of the water, but you're also using only some of the grounds.  The brewing ratio isn't actually 1 to 15.8.  It is a completely variable brewing ratio depending how many grounds happened to be floating and how many happened to be up against the paper filter at any moment during the downpress.  OK, I realise there is also a 'full immersion' element of the brew, not just what is going on at the point of contact with the filter, but since 50g of the slurry is being discarded (along with the extracted solids sitting in that slurry) then the effect of full immesion is reduced, and the brewing ratio is still very difficult to quantify. It is also, arguably, impossible to repeat with any level of consistency.

I'm not being critical of this brewing technique at all, by the way.  I'm just trying to understand it more by putting my thoughts down on this blog.

So whilst writing this blog post I've been finding and reading a few forum and blog posts... notable the following:
1. A thread on coffeegeeks, with some useful links.
2. One of those links was to the ever-useful blog of Marco's David Walsh, and this post (good comments below it too).
From the above reading I found that it's quite common for AeroPress brews to be updosed and underextracted (rightly or wrongly).
"So does this suggest a kind of mass hysteria among speciality coffee folks, a laziness in technique due to increasing bean quality, or perhaps that the 50+ year old standards are inadequate?
The answer is probably not 100% any of the above"  - David Walsh
Anyway, I'll keep reading but I'm now at the point where I want to at least try, as I said in my last blog, updosing my AeroPress brews.  I'll start at 1:15 and get increasingly stronger.

After that I'm thinking of going back to 1:16 and varying other parameters... grind, maybe even the grinder itself, perhaps using two filter papers rather than one to increase TDS (as suggested by Roland Glew), etc etc.  

Must remind myself where I'm going with this!  I'm initially aiming to get inside the 'ideal' brewing zone. Using that as a foundation, I'll then adjust parameters until I find out what my palate likes in terms of TDS and Extraction %.

Now, since this post has ended up longer than I expected, I'll hang on until tomorrow to post actual brewing results! 

Monday, 24 October 2011

Dialing in the AeroPress (2)

Since my last AeroPress brews I've been having a think about how else I can tweak the brew parameters to reach my target extraction.  I've tightened the grind, I've tried different press speeds, I've allowed the steep time to encroach upon 1min 30 secs, which I think is more than reasonable for this brew method and I wouldn't want it to take any longer. So two questions remain:
  1. Why isn't the TDS higher?
  2. How else can I increase it? 

Why isn't the TDS higher
I need to continue thinking about this more, but I think I'm not getting a good enough diffusion process to pull out the solids from the grinds. Possible reasons (ignoring the parameters already mentioned) include:

  • Water temperature too low... I doubt it. I'm being very careful here (remember the übercosy?)  although there's a balance to be found between the longer steep time and temperature loss.
  • Dose too low.
  • Problems with the grind ... perhaps particle distribution rather than size setting. The Ggggia MDF isn't a bad domestic grinder at all... underrated in my opinion... but perhaps there are issues that I hadn't considered.
I shall continue to muse, but in the meantime I'm going to increase the dose as it is the easiest one to vary.  It may reduce some of the sourness I'm getting too... which I'm sure isn't coming from low brew temperature.

I typically work to a 1:16 ratio but I'm going to go richer, first trying 1:15 and seeing how it goes.

(As an aside, at this point in time I prefer working to brewing ratios in the format of 1:15 - i.e. weighing the grinds AND the water - rather than, say, 60g/litre. My preference stems from my espresso approach to brew methods... there is now (finally and thankfully) a trend towards using weight to measure and control espresso shots. For example, Square Mile have the following sugggested brew parameters for an espresso on their website:

18g in  ... 27-29g out.
Using a consistent unit of measure just seems more appropriate to achieving consistency.)

Brew (I've decided to stop numbering them!)

To be updated later today...
Nope... had to take Lulu the cat to the vets. Updated another day :)

Monday, 17 October 2011

Dialing in the AeroPress

French Press... tick
Hario V60... tick
Time to get a better grip on the AeroPress.

The first thing I wondered was 'should AeroPress coffee be brewed according to the Brewing Control Chart?'
It's arguably a different beast... not immersion, not pourover, and definitely not (as it claims to be) espresso . People tend to talk in terms water volumes with the A/P (e.g. "fill it up to the number 4 marker") rather than weight... and the variety of approaches to brewing with it don't all seem to follow the typical 1:15, 1:16, 1:17 type of ratio.

But ultimately, after running a few preliminary cups and reminding myself how it tastes, I've decided that it's still brewed coffee and simply a hybrid of French Press and Filter, despite the pressurised element. (I'm thinking that perhaps the main benefit of the pressure plunge is to increase agitation to provide a faster extraction of solids.)  I therefore do need to work by the charts.  I'm also, at least initially, using scales rather than markers - although I expect that will change once it becomes clear whether the marker can consistently represent a certain weight of water.

First Brew
I brewed directly into the cup, which holds about 250g of water, so that's the amount I used to brew with... and therefore using approximately a 1:16 ratio I measured just over 15.5g of bean, grinding and then ensuring that was the weight I ended up with in grinds.
Setting 10 on the Gaggia MDF grinder.
Honduras, Finca Santa Marta Lot 232, Pacamara, roasted by Paul Travis at Hands-On Coffee in Wadebridge, Cornwall.
- Approx 40-50g pre-wet, with a little bit of blooming then seven or eight stir... all in about 30 seconds.
- Fill to 250g, which is around the number 4 marker
- Place the plunger on to create a vacuum, preventing dripping into the cup (I'm not inverting the A/P).
- Leave for 30 seconds... hence an element of full immersion

- Plunge, taking 30 seconds to reach the bottom... stopping at the first sign of a hiss of air.

It tasted good.  More acidic than the V60.  It was heading a little into the sour range though.
Taking a reading helped explain why. Although the temperature in the cup was fine at 67C, the TDS was a little low at 1.12% (bearing in mind I tend to aim for between 1.15% and 1.45%, as a combination of SCAA, SCAE and Nordic controls). Extraction Yield was 18.1%, which is fine.

Second Brew
OK, so I thought maybe this time I needed to stir more just before plunging, which I did.
However, the TDS this time was only 1.05%, and Extraction Yield 16.9%... and it was more sour.  Why? Well I did plunge slower ... around 35 seconds. Maybe there was less agitation because of that, and I need to plunge quicker to get the TDS higher and extract more solids. Alternatively I know I could simply grind finer, but where's the fun in that? :)

Third Brew
I had a change of heart and tightened the grind from 10 to 9. I also plunged faster... around 22 seconds.
Result: TDS of 1.17%, Temperature 66C.
Tasted great and left a fantastic buzz on my lips and the roof of my mouth.
Although the TDS is within target, it's still at the low end of the range. Let's try again and aim for around 1.35%.  Perhaps this will need a grind setting of 7...

Fouth Brew
Grinder on 7, a 20 second plunge. Doh! I forgot to stir a second time just before the plunge. That stir is critical, since the TDS ended up being only 1.10%. Taste... sour.

Onwards and upwards/downwards...

Saturday, 8 October 2011

A Giant Leap Forward In Pourover Coffee

Maybe I'm gettting old, I dunno, but for some time now I've been veering towards old ways of doing things. Not just in coffee, but in my whole life. I want my own raised beds to grow vegetables. I'm baking bread rather than buying it.  Jan and I have started foraging, since all this lovely wild food is right on our doorstep.

And so it is that when experimenting with pourovers recently, and finding that I'm losing valuable degrees of water temperature during the brewing process (making the coffee slightly sour) I went straight to an Old School solution rather than look at investing in fancy, expensive boiler systems incorporating digitally controlled temperature stability.

And here it is.  I give you... the Übercosy (TM).

- Unlike previous cosies, the Übercosy (TM) provides direct access to filling the pouring kettle with boiling water without removing the cosy, via it's unique 'cosy inversion' technology ... a revolutionary approach involving placing a hole at the top of the cosy rather than the bottom. Until now filling your kettle involved removing the cosy altogether, thereby losing at least two degrees celcius in water temperature.
- The secondary benefit of the 'cosy inversion' technology is that heat is retained at the base of the pouring kettle, whereas previous cosy designs had a large area of exposed metal at the kettles underside, allowing further heat loss.
- A drawstring with hand-made toggles enables the user to gain RCC (Rapid Cosy Closure).
- It looks spiffing.

Concept and Production

Its creation involved a crack team of little old ladies working as a thinktank to meet my exacting specifications.  Think of it as me being James Hoffman in this video and the grannies being the R&D department at Marco.  First, my mother-in-law conducted the all important requirements-capture stage. The requirements were then sent to Auntie Kate in the production department. She was able to recruit specialist consulting from an outside contractor, an independent granny, who completed manufacture of the prototype.  Whilst the product at this stage met many of the requirements, it did not yet incorporate 'cosy inversion' technology.  My mother, using a patented 'wool-unravelling' concept, successfully sealed up the offending hole at the wrong end, added the drawstring at the other end, thereby accidentally inventing 'cosy inversion'!

Your Mother's Always Right

When asked how she felt about having created such a world-changing invention, paralleling the works of bygone luminaries such as Steve Jobs and Thomas Edison, she said "I just turned it upside down, yer silly sod". Wise words indeed.