Extracting Bad Flavors Through Pre-Soaking and Coffee Kombucha

Green Coffee Beans

As I attempt to decaffeinate green coffee an experiment comes to mind. When roasted coffee is brewed there is a target percentage of extraction that is “ideal.” Using a refractometer it is possible to calculate this percentage and have a picture of extraction that is not as subjective as taste. If the brew is under this percentage the cup is defined as “under-extracted”. As far as Im concerned, this means that not enough of the good tasting, water soluble substances in coffee have been extracted from the grounds. When the extraction measures above this percentage then it is defined as “over-extracted”, and means the opposite: water soluble substances that have an unpleasant taste have been extracted.

I recently started experimenting with the decaffeination of green coffee. Caffeine is water soluble and simply soaking the beans in water should remove a large amount of this alkaloid. The downside is that this soaking also removes a lot of the flavors associated with coffee. At least this is what you hear about the decaffeination process: a lot of valuable flavor is lost during the process. However, what if soaking for a pre determined amount of time, established through experimentation and specific to particular coffee, would remove some of the non-desriable tastes of coffee found in an over extracted cup? I can see the question being posed: What benefit does this pose? Well if this were to be true then our extraction percentages could increase without the brew becoming over extracted. That is, we could potentially have more access to flavors generally not obtainable through regular roasted coffee. Yes, there would probably be some loss of valuable attributes but Im willing to find out what the outcome is. The experiment goes something like this. Using a 5 pound batch of green coffee, soak 4 pounds for different lengths of time (15m, 1h, 4h, 12h) and keep a pound dry as the control. Then dry the soaked beans and roast them. Cup and taste the results. If the cupped results are not horrible then we can move on to purposely “over extracting” these pre soaked roasted beans. The hard part is drying the beans after they have been soaked and purged of the caffeinated water. It is easy for these the beans to mold, rot, or ferment if not dried evenly and appropriately. Also, I am concerned as some of the beans have sprouted. Exciting because I can separate these and try to grow some coffee shrubs but unfortunate because those cannot be roasted. I will post the results of my experiment.

Another experiment came from this. I have previously tried making Kombucha with brewed coffee. The Kombucha culture feeds off of caffeine and sugar and coffee seemed like a great medium for its growth. All my trials ended up in a dead culture because of the high concentration of oils in brewed coffee, even if brewed through paper filters. I had put this endeavor on pause until now. Having all this caffeinated water from soaking the green beans resisting putting it down the sink sparked a thought. What if I used this water and sugar to brew “coffee” kombucha? The kombucha is jarred and the culture seems happy. I am hoping for a delicious probiotic drink.


[image: http://www.alti-coffee.com/coffee/green-coffee-beans/]

One Response to “Extracting Bad Flavors Through Pre-Soaking and Coffee Kombucha”
  1. fabian11 says:

    I hope the brewing works out and you get a probiotic drink. But do you think it is going to have any coffee flavor?

    Have you thought about seperating the oils in brewed coffee from the caffeine and flavors? Or are all flavors in the oil?

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