Phantom Potato

February 5th, 2009

We cupped a few coffees today, and in there were a few from Rwanda.  Whenever Rwandan coffees are on the table the conversation inevitably turns at some point to potato.

For those who have no idea what I am talking about I should explain.  There is a defect in coffee that is referred to as potato.  It is the result of a bacterial infection of the seed, usually after being bitten by an insect carrying that bacteria.  Once roasted that particular bean carrys very, very strong aromas of freshly peeled potato skins that is incredibly potent when you grind the coffee and when you brew it.

Unlike many other defects you can’t tell if a green or roasted bean has potato in it until it is too late.  The solution to the problem is very labour intensive.  When the cherries are picked any cherries that show signs of damage are discarded, and this process is usually done by hand.  After the washing process, when the parchment coffees are still very wet it is also apparently possible to see the damage and discard the beans at that point.  However if a bean has been missed and is dried then it is undetectable until ground.

The potato defect is a problem in several countries, but has become more of a talking point as Rwanda has risen to prominence as producing country capable of stellar coffees, but also a producing country that has problems with potato.  I don’t want to rattle on too much about it – I highly recommend reading this thread if you want to know more about the potato defect.

The real point of this thread is to talk about the weird psychological effect that potato had on me, and ask if anyone else suffers this.  Once you smell potato a few times in a coffee you are using you become hyper sensitive and a bit paranoid.  Cautiously sniffing for even the faintest sign of potato.  The Nyamagabe lot we used in Stephen’s WBC espresso suffered from potato, and we went to ludicrous efforts to prevent it 1

It snuck up again in Copenhagen – during the Cupping competition I was stood near the prep area, next to Edwin from Finca Vista Hermosa, and we both caught the distinct potato peelings smell in the air.  That cup was pretty easy to pick out!

After the lot of Nyamagabe was finished I thought I would be able to relax, but still the smell haunted me.  Every now and again I’d find myself sitting bolt upright in the roastery, sniffing the air thinking “Is that potato?? IS THAT POTATO??” before remembering that it couldn’t be, and that I was loosing my mind.

Am I the only one?  Does anyone else who has experienced potato a bit get somewhat paranoid about tuberous smells?  Am I making quite a public fool of myself?  You decide…..

  1. We packed all the Nyamagabe component seperately in 500g bags that were sealed.  Before use we’d carefully open each bag and elimate any that showed even the slightest waft of potato before blending with the El Bosque.  Regardless of this – the final practise shot on stage before the finals there was a clear and terrifying *poof* of potato flavour that filled the stage.  We hoped lightening didn’t strike twice!  ↩︎

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