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Experiment: Boiling Cold-brewed Coffee

2010 January 26
by Mad Alchemist

I love to experiment. I also love putting coffee in porters and stouts. It’s a flavor I find to be complementary. I recently posted about adding cold-brewed coffee to beer, and mentioned that I wanted to test boiling cold-brewed coffee to see what it tasted like. Well, I’m not very patient, so I already did it (note: I haven’t added it to beer yet–this is a standalone coffee taste experiment).

8 oz whole coffee beans
4 cups water (Brita-filtered in this case)


  • Coarsely crushed the coffee beans
  • Put 4 cups of water in a large measuring cup
  • Added the coarsely crushed coffee beans to the measuring cup in a muslin bag
  • Put it in the refrigerator for 12 hours
  • Pulled the bag out, let it drain for 15 minutes
  • Steeped the bag again, then let it drain for 15 more minutes
  • Split the solution in half (~16 oz in each measuring cup)
  • Set Solution A aside
  • Boiled Solution B in a pot for 10 minutes
  • Rapidly cooled Solution B by immersing the pot in cold water in the sink
  • Added Solution B back to its measuring cup, then diluted it back to 16 oz
  • Put Solution A and Solution B in the refrigerator for 12 hours


  • After removing the two, I tasted them both.
  • I first took a sip of water and sniffed my wrist to cleanse my palate.
  • Then, I took a small sip of Solution A (the normal cold-brewed coffee)
  • I then took another sip of water and sniffed my wrist to cleanse my palate.
  • Then, I took a small sip of Solution B (the boiled cold-brewed coffee)

In short, they did not taste the same. Solution A tasted like I would expect cold-brewed coffee to taste. It was mild with very little bitterness whatsoever, and was quite pleasant. The real surprise was Solution B. It was stronger and fuller, but still had very little bitterness or astringency. It had a slightly-caramelized and roasted taste to it. My wife described it as such: “It tastes like coffee smells.” – Mrs. Hop.

Boiling cold-brewed coffee produces a solution that tastes unlike both cold-brewed coffee and normal hot-brewed coffee. It was quite delicious indeed, being both bolder than cold-brewed coffee and less bitter than hot-brewed coffee. I will certainly be introducing boiled cold-brewed coffee to my next batch of porter or stout.

7 Responses leave one →
  1. Chris permalink
    January 3, 2011


    been reading your prose all over the net this week, trying to get a handle on adding coffee to a porter. I think this method above is the most attractive to me.

    When are you introducing this in your beers, in the keg or a secondary?

  2. jessie permalink
    January 4, 2011

    sounds great! we will try this with our espresso amber and tell u what we think. thanks, very through description

  3. January 17, 2011

    I’ve tried introducing cold-brewed coffee at several stages. It seems to be quite successful when bottling. I boil my priming sugar (i.e. corn sugar, dry malt extract, etc.) with the cold-brewed coffee for 10 minutes and add it to the bottling bucket.

    This tends to give me the best bang for the buck on flavor.

  4. February 26, 2011

    Your experiment is just what I’ve been looking for. I’m going to to try both methods in a stout and see how they turn out.

  5. Brian permalink
    May 11, 2017

    Makes sense. The bitterness and astringency is left in the discarded beans which are not exposed to the heat. And the boiling would take care of the sanitization, too, as well as reducing the solution to be less watery. Great work, thanks!

  6. bennett permalink
    August 1, 2018

    Hows does boiled cold brew coffee compare to quickly chilled normal hot brewed coffee?? For the sake of completeness. This sounds like a cool experiment, I would try mixing porter/cold brew mix.



  7. August 3, 2018

    Cold brew has much less acid and is considerably smoother.

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