Coffee Data Science

Vinegar Soaking Robusta Coffee

A quick test on some research

Robert McKeon Aloe
3 min readMay 31, 2022

For the past six months, I’ve been very interested in processing methods for coffee. I started looking up methods applied to robusta coffee. I found one on Modifying Robusta coffee aroma by green bean chemical pre-treatment. So I decided to try it out using apple cider vinegar.

Long story short, I think I over developed the roast.

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The theory in the paper was that a treatment of the beans before roasting could reduce the amount of arabica needed to blend with robusta to make a good blend. I was curious if it could take a robusta and make it better.

I chose one I had from Sweet Maria’s. I had made some blends before with this robusta, but I wasn’t sure if it was adding better flavors. The trouble comes when roasting because robusta roasts differently due to the difference in bean density.

I let them soak in a 2% acetate solution by diluting 2 parts apple cider vinegar with 3 parts of water.

Then I rinsed them and dried them using a dehumidifier function on my oven.

I roasted, but then ended up being pretty dark.

I wanted more immediate results, so I did a cupping with a sourdough yeasted bean from El Salvador and an Ethiopian bean aged in a whiskey barrel.

Based on smell alone, I knew I messed up the robusta.

The whiskey barrel aged coffee tasted like whiskey. The sourdough one was alright.

While this experiment certainly failed, I still wrote it up because I thought it was a odd way of processing beans. I also wanted to bring attention to robusta because what it lacks in sweetness, it makes up in mouthfeel. I would try again, but I’m in the middle of a larger set of experiments involving different yeasts and coffee beans.

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Further readings of mine:

My Future Book

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Collection of Espresso Articles

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Robert McKeon Aloe

I’m in love with my Wife, my Kids, Espresso, Data Science, tomatoes, cooking, engineering, talking, family, Paris, and Italy, not necessarily in that order.