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  • cold coffee?

    Does anyone have experience with cold coffee they want to share?

    specifically i am concerned about micro/ food safety issues, as well as steeping program.

    I was thinking about taking carbon filtered water from my hot liquor tank and chilling it through the heat exchanger as with a regular beer. this way i could assure the water was sterile. With beer because of alcohol/ hops/ pH we can be assured that pathogenic organisms cannot survive, but coffee may present a problem here? also are there sugars extracted that could subsequently ferment and cause cans/ bottles to explode?

    I also wonder about steeping temperature/ time, i could get 10C and have heard 12-18Hr talked about. What does longer/ shorter time result in?

    Finally, i saw a post referring to using whole unground beans rather than coarse/ fine crush. I presume uncrushed would take longer but does it work?

    thanks for the feedback.

  • #2
    cold brew

    We make cold brew and use a straight tap water soak for 15hrs. Then we filter to 55um and transfer to our brites. We pasteurize after packaging in bottles and this gives us 6 month shelf life if kept refrigerated. PH is mid 4's, so requires some sort of kill step/ preservatives to keep the buggies away.

    mtn

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    • #3
      great, thanks

      any reason for the 55um size? just to get the grounds out? I was thinking about steeping in a horizontal conditioning tank so they could settle on larger surface area and have less height to drop out and then racking it out the arm.

      The pasteurizing sounds like a responsible thing to do but we are not set up for it right now, we might do a pilot project making kegs for the coffee shop chain before deciding to go bigger. Often breweries use a .45 micron filter to sterile filter beer with the idea that nothing that can ferment beer will get through. don't know how well coffee would work going through one though?

      The other concern is with oxygen pickup. is it an issue with coffee? I feel like pastuerizing a product with high do might be a problem?

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      • #4
        Lot's of sediment in ground coffee and 55um is a good balance for us time vs. quality. We start at 400um and work our way down. Crashing the sediment/ grounds will help a lot but i'm not sure how much fines will remain with that process. I would assume you'd loose something at 0.45um, but worth a shot and taste test. We push our coffee around with N2 which helps keep the O2 out, but i've never been able to test for oxygen levels and we've never noticed an issue or had complaints.

        mtn

        Originally posted by beerme View Post
        great, thanks

        any reason for the 55um size? just to get the grounds out? I was thinking about steeping in a horizontal conditioning tank so they could settle on larger surface area and have less height to drop out and then racking it out the arm.

        The pasteurizing sounds like a responsible thing to do but we are not set up for it right now, we might do a pilot project making kegs for the coffee shop chain before deciding to go bigger. Often breweries use a .45 micron filter to sterile filter beer with the idea that nothing that can ferment beer will get through. don't know how well coffee would work going through one though?

        The other concern is with oxygen pickup. is it an issue with coffee? I feel like pastuerizing a product with high do might be a problem?

        Comment


        • #5
          awesome, thanks

          i am going to do some pilot extractions with several growlers at various concentrations, times and grinds. the idea of using unground beans is appealing from a processing point of view to avoid filtration issues. the tank i plan to use has a 3" outlet, so getting whole beans out should not be a problem.

          I am still looking into microbiological stability issues, specifically if anyone can point me to literature on what can grow in cold coffee, please share.

          I will add to this thread when i have more results.

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          • #6
            Whole beans sound like a win, but around here we're paying $20/ kilo for the stuff...

            mtn

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            • #7
              Originally posted by Mtnmann View Post
              cold brew

              We make cold brew and use a straight tap water soak for 15hrs. Then we filter to 55um and transfer to our brites. We pasteurize after packaging in bottles and this gives us 6 month shelf life if kept refrigerated. PH is mid 4's, so requires some sort of kill step/ preservatives to keep the buggies away.

              mtn
              I'm working on a project with a local coffee roasting company on scaling up their cold brew using my equipment. Currently, they make small batch cold brew for their own cafe but have been approached by retail locations about having cold brew on tap which changes the health guidelines. If we use cold water, the guidance from health department is that the product either needs to have ph of less than or equal to 4.7 OR be held at below 40 degrees. Did you add any acid to get your ph into mid-4's and if so which acid? With the process they've used before, they're getting ph in mid 5's. Any input or suggestions are appreciated

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