Ask the Alchemist #152


I have an Italian espresso maker with individual control of brew temp and pressure and I would like to start making "mocha" shots, 50/50 coffee/cocao. Any suggestions on a particular bean, grind, proportion, or technique to get started.

I am an totally coffee geek.  I have my own lever espresso machine.  I just finished a lovely 1.5 oz burnished  auburn 80% crema shot, silky, thick and lingering.  And oh how I've wanted that same experience with chocolate. You can imagine it, can't you?  Heady chocolate, heavy in the mouth, coating and lingering for what seems like hours.  You want it.  I can tell.  Me too!!

naked

Alas, it is not to be. That's the hard truth.

It is not for lack of trying. I've have tried.  For years.  So this is going to be a story of failure.  But that's ok.  We learn things.  And maybe.  Just maybe.  Someone will have inspiration and stand on the shoulders of my research and succeed where I (and others) have failed.

Let's get out of the way what I have tried.

100% Cocoa from raw to virtually burned (ok - burned!)

90% Cocoa/10% coffee down to 10% cocoa/90% coffee in 10% increments

100% Cocoa nibs

Cocoa nibs with varying percentages of cocoa husk mixed back in up to 85% husk.

I tried all of these with various grinds from very fine to very very coarse.  I mixed fine with coarse and coarse with fine.

The results.  Well, they sucked.  No two ways about it.  I simply can't tell you all the results.  There are just too many. But I can give you the run of how it went.

First and foremost, cocoa does not want to pull.  You know that oil and water not mixing thing?  That pesky seizing thing chocolate does in the presence of water?  Well, add pressure (yep, varied that to from 2 bar to 15 bar) and hot water and it just makes matters worse.

That is the very first hurdle you have to get past.  In coffee you deal with a stalled shot by making the grind less fine, using less coffee and/or tamping less hard. None of these worked for cocoa.  In coffee espresso things are more or less linear.  There is a broad(ish) window.  10% less coffee, 10% coarser grind, 10% softer tamp (sometimes) give you SOME result differences without the shot turning into a gusher.  Meaning you don't go from a stalled shot with an infinite pull time to one that pulls in 5 seconds.  It goes from stalled, to maybe 50 seconds (for 2 oz).  10% more gets you to 30 seconds.  3% more gets you 24 seconds and a good shot.

No so in cocoa.  It isn't linear.  It's like a cliff.  And it's a steep on.  You go from stall, (10% change), to stall (10% change), to gusher.    Smaller step?  5%?  It's damn near binary.  Either it stalls or gushes.  There is no middle ground.

All those other combinations were my way of trying to find some middle ground.  And to some degree I did.  The addition of either husk or coffee (basically reducing the oil content) allowed me to get something that pulled in something resembling a decent time, (15-45 seconds).  I was thrilled.

Unfortunately the taste was terrible.  Another cliff.  Either the shots were watery and insipid or so bitter and vile that there was no acquiring a taste for them.  They were just bad.  Oh, and of course I tasted those initial gushers - watery and insipid, for the record.

And that was it over and over.  Find a combination, dial it is so it was something you could actually pull, and time and again, the result was one extreme or the other.

I tried sifting the ground cocoa to get a very narrow "perfect" range of grind.  And I actually made moderate progress here.  I could get ok shots, that tasted not terrible.  It's honestly the closest I ever got.  Unfortunately the results were near to impossible to reproduce due to steep cliffs on both sides.  One cliff was dose (how much).  The other was tamp pressure.  0.5 gram difference in dose could be the difference in stall and gush.  And same with tamping pressure.  It had to be 'just so'.  A 2 lb difference would drop you off the cliff.   Basically, it gave me results I could not share as they were just too fussy.  Even knowing the variables I could not pull 3 good shots in a row.  Oh, and the taste of the good shots?  Meh!

On a similar note.  To give credit where credit is due, I was sent once some specially ground "100% cocoa beans" for espresso.  It actually allowed me to pull shots with minor dial in.  Sadly the results were the same as I had before.  Nothing I actually wanted to drink.  Kind of bitter in a bad way.  Some cocoa aroma, but watery and no really chocolate flavor.  Certainly not the droid I was looking for.

To be fair, there was one other option.  When mixing with coffee, somewhere around 70-80% coffee I could get a pretty good time window, the shots were not watery nor vile....but they also had no real cocoa flavor.  They were just mediocre (to bad) coffee espresso shots.

That's about it.  For those of you who know Venn diagrams, this was kind of it.

cocoa espresso venn

There just don't appear to be any overlapping sets of "Cocoa Percent" and "tastes good".

I'm off to pull another naked espresso shot (the portafilter folks, the portafilter! - google it)

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