Sunday, April 25, 2010

An Aeropress Recipe Collection (And Why It Doesn't Matter)

Introduction

My espresso machine has been with some dude having some modifications done to it and my housemate has been convincing me of the virtues of the aeropress. I was pretty sceptical of it initially because of the infomercial type advertising (snuggie eat your heart out) and the rave reviews from people brewing hyper-concentrated brews and re-using the paper filters 15 times (I kid you not), bu it's pretty hard to argue with it on the convenience front and it is true that it allows you to control pretty much all of the variables, so I have been experimenting with it a bit over the past few months. One of the things that I found irritating about it was finding info on how to use the thing. So, without further ado, I present you ...

An Aeropress Recipe Collection

Manufacturer's Instructions (pdf)

Wendelspro

Wendelblog (I think the above is updated)

Varney's Kenyan Brew

Anders Valde, 1st Aeropress World Champion (Woo! Yay!)

2009 Aeropress World Championships Top 3

Tristan Stephenson

Scott Marquand

Klaus Thomsen

Tom Owen (You Tube)

Why It Doesn't Matter

If you read through all of the above, you will find that they are pretty different. I'm sure that a big part of the difference is due to the difficulty in communicating grind size. (And the associated extraction info.) That, and the massive variety of taste preferences - people often put forward their preferences as the best without explaining why. Actually, that's a good point, so I might reiterate:

People often evaluate without describing.

For example; I was suprised at the strength of one Japanese siphon champ's preferred brew.

In other words, at the end of the day you have to adjust coffee based on taste, which brings us to ...

The Gold Cup

As with any other brew method, aeropress brewing follows the gold cup fundamentals. The gold cup has an interesting history, which is well summarised by Paul Stack here, but it basically comes down to something like this:

Good Coffee = Extraction of the right compounds to the right strength

Extracting the right amount of stuff basically means not underextracting (and having a cup that lacks flavour) and not overextracting (and having a cup that is bitter), but rather getting the right amount of flavour. The range 18-22% has become canonical; this means that, for example, if you grind 20g of coffee, 3.6 to 4.4g of it should end up dissolved in your cup. From memory, the number seems to have come from the early experiments (read Paul's post) and now that we can very easily calculate extraction using a nice refractometer and calculator, I think that we should all be repeating these experiments. From memory, for example, I think that Mr Howell likes to extract his delicious coffee to a narrower range within that 18-22% range.

The right strength is the other main matter of taste. From memory, the SCAE standard is about 1.3% TDS, whereas the SCAA standard is a bit lower. This means, in the case of the SCAE gold cup standard, that 1.3% of the volume of liquid should be coffee extract.

Got it? Simple? Should be.

(As a side-note, I did the SCAA gold cup certification last year at the Atlanta expo. Repeating the name "E. E. Lockhart" a million times made it feel a bit much like a remedial primary school history class for my liking, so I hope that my certificate arrives soon. A friendly follow up email is in order, methinks.)

(As a further side-note, Mark Pendergrast's book Uncommon Grounds mentions that initiatives such as the Coffee Brewing Institute, which did the research for the Gold Cup standard, was backed by the Pan-American Coffee Bureau. In other words, whilst the major US coffee roasters were busily squabbling amongst each other in the face of decreasing share of the beverage market, it was coffee farmers footing the bill to improve the standard of coffee consumption in a land far distant from them and to consequently increase market share for their customers.)

Variables

The whole point of the Gold Cup is to learn how to change strength and extraction to improve your cup. Doing so requires you to change variables. Fortunately, the Aeropress gives quite a lot of control:
  • steep time
  • stirring
  • grind
  • water temperature
  • coffee/water ratio
My Recipe

So at long last we come to my recipe. I imagine that this will be useful for no-one, seeing as it is very specific to my setup. To start off with, we noticed that the cups we were getting were quite bitter. It turned out that the culprit was the grinder that I was using. Big conical burr grinders might be the bees-knees for espresso, but aeropress proved to be a challenge for my Kony. The problem was solved by removing the finer particles using a drum sieve. The resultant grind was then not yielding enough per gram, so the weight had to be increased from a standard 55g/L ratio. All of which means that the following is probably fairly useless, but I'm going with more or less:
  • 22.5g coffee (post-sieving)
  • ~200mL water (a few minutes off boil)
  • stir coffee one or two times
  • 1 min 50 sec steep time (inc 30 sec plunge time)
  • dilute to taste.
Works for me at the moment. At a guess, I'd say that I'm probably at about 1.25% TDS by taste. Extraction is probably on the lower end, but I do notice bitterness if I let it steep much longer. Yes, I'm looking at getting a better grinder for filter. The ceramic burr hand grinders that I have tried so far have been pretty woeful.

I have been using the inverted method, though Tom Owen points out that if you fit the bits together, a vacuum forms to stop more coffee leaking out anyway, so I might try that. As a practical matter, it depends if you're comfortable with the risk of catastrophe if you can't fit the filter properly with the press inverted. As a taste matter, I suppose it depends if you want your coffee sitting up against a bit of rubber or a bit of paper - neither of which sounds attractive. I will probably have a go at making some cloth filters at some stage.

Of course, the absolute best thing about it is that clean up takes 2 seconds!

Updates!

It may be useful to keep a collection of Aeropress recipes, so if you have any links that you would like me to add, let me know ...