Announcement

Collapse
No announcement yet.

Bizarre milk seperation problem

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    Originally posted by MrJack View Post
    I still think it is likely acid in your boiler water. Did a quick google, and would like to present my hypothesis

    According to The CURDLING of MILK the micelles (small droplets of oil/fat with an outer layer of protein, suspended in water) become unstable at a pH around 4.6. When this happens, the protein molecules are attracted to, and get entangled in, each other (i.e.becoming curd).

    I suspect your have water with a low pH, but not quite as low as 4.6. The addition of coffee, tips the pH over the edge, and curdling results. Its also possible that other molecules also play a part. Micelle stability is also related to concentration and temperature, so its possible that these factors come into play also.
    Why not buy some PH test strips and test the water.
    Find it hard to believe this thread is still lumbering on without a solution, can only be the water, coffee or milk, not a difficult problem to solve.
    The elephant in the room is water.

    Comment


    • #32
      Years back, I worked for a company with an full auto machine (Saeco?) and one morning I went to get my coffee and when I tasted it, it was strange. I sat it down while getting some water to rinse my mouth and when I got back it was curdled.

      Turns out the guy who had run the descale process hadn't rinsed the system and walked away from it. I was off my face for a couple of hours from the cleaner.

      From that day on, I looked after the machine, including putting up a sign while the process was running with POISON in extra large letters. (budding CS'er even back then apparently )

      @Heks12 - you didn't answer Yelta's Q about whether you have thoroughly rinsed your machine with water... Did you try that?

      Comment


      • #33
        Originally posted by JourneymIn;I14932
        Years back, I worked for a company with an full auto machine (Saeco?) and one morning I went to get my coffee and when I tasted it, it was strange. I sat it down while getting some water to rinse my mouth and when I got back it was curdled.

        Turns out the guy who had run the descale process hadn't rinsed the system and walked away from it. I was off my face for a couple of hours from the cleaner.

        From that day on, I looked after the machine, including putting up a sign while the process was running with POISON in extra large letters. (budding CS'er even back then apparently )

        @Heks12 - you didn't answer Yelta's Q about whether you have thoroughly rinsed your machine with water... Did you try that?
        Arghh..not a good story!
        Yeh I answered that Q this morning - I did flush it thoroughly with bottled and am only using bottled, but its still happening. Thats why I dont think its the water but perhaps something in the machine thats turning the water bad. Ive made over 20 coffees since it was last descaled I struggle to beleive that any acidic residue could possibly be remaining.
        Ph strips and a high quality espresso machine descaler arriving this week, hopefully this will come to an end.
        Thx for everyones input so far.

        Comment


        • #34
          Oops... didn't see that line. My bad.

          How did you descale? Could it be possible a chunk of a descale tablet broke away and is sitting in a pipe somewhere? Has the performance of your machine altered in any way? (slower to pour a shot, steam different, only one side of the showerscreen releasing water etc.)

          Comment


          • #35
            Heks,

            As per my post #14, was this happening before you descaled the machine?

            Have you tried warming a cup of milk in a microwave (or on stove top), then adding espresso from your machine?

            Cheers
            BOSW

            Comment


            • #36
              Originally posted by Barry O'Speedwagon View Post
              Heks,

              As per my post #14, was this happeis no ing before you descaled the machine?

              Have you tried warming a cup of milk in a microwave (or on stove top), then adding espresso from your machine?

              Cheers
              BOSW
              Yes & Yes.
              No problem occurrrd adding microwaved milk.. my theory being because there is no foam.. as i was saying ear
              Ier its the foam that seperates and curdles into the coffee. I can use the steamer and as long as there is absoluety no foam itll often be ok too.

              Comment


              • #37
                From here on I'm just gonna sit and watch (this thread) interested in the eventual solution.

                Comment


                • #38
                  Steaming the milk will add water which could affect the stability of the micelles by changing the concentration (Google critical micelle concentration & Krafft temperature).
                  Also, foam is a different type of colloid, which is likely less stable than the milk.

                  So it's plausible that what you are experiencing is not because of something 'wrong' with your steamed milk, but just that the steamed milk is by its nature, less stable.

                  Keen to see what pH it comes to. You got blue litmus, right?

                  Comment


                  • #39
                    Originally posted by MrJack View Post
                    You got blue litmus, right?
                    ..which tempted me to break into an Elvis impersonation: "But I'll have a blue, blue, blue, blue litmus"

                    Comment


                    • #40
                      Originally posted by heks12 View Post
                      Yes & Yes.
                      No problem occurrrd adding microwaved milk.. my theory being because there is no foam.. as i was saying ear
                      Ier its the foam that seperates and curdles into the coffee. I can use the steamer and as long as there is absoluety no foam itll often be ok too.
                      When you say 'absolutely no foam' I wonder about technique - perhaps your machine is delivering hotter steam now (for whatever reason) and you're creating froth on top of your milk? When you finish making the milk, take a spoon and scoop some of your foam up. If you turn the spoon upside down does the foam hang on the spoon or does it run off as you turn the spoon?

                      When I'm in a café I have long macchiatos. Some places stain the coffee with the milk and then add a dollop of froth (I have no idea why) and even after stirring in the sugar, the froth is still there. It has been heated past the point where it will mix with the coffee. My wife calls the stuff 'porn froth' as when I did the course, the instructor explained that was how cafés made capps back in the 70's, and now we should be trying to NOT make 70's froth. She promptly dubbed it porn froth.

                      Could you make a video of your process or even just post some pics of what your finished product looks like? ( before you add it to the coffee...)

                      Comment


                      • #41
                        Journeyman, didn't your wife write 50 Shades of Grey or something like that? Better keep the video in AO section of the site.

                        Comment


                        • #42
                          Originally posted by heks12 View Post
                          I did flush it thoroughly with bottled and am only using bottled
                          Hmmmm........... so .......... some bottled water has aluminium residues in it ( In Australia bacteria, chemical disinfectants and aluminium have been found in bottled water samples.)

                          Aluminium sulfate is used to purify water.

                          Aluminium sulfate is used to curdle milk.

                          Just a thought but you could spend 1/2 a day completely purging your machine, fill it with tap water and see what happens.
                          Maybe something, maybe nothing.

                          Comment


                          • #43
                            Originally posted by Barry O'Speedwagon View Post
                            Journeyman, didn't your wife write 50 Shades of Grey or something like that? Better keep the video in AO section of the site.
                            Someone needs more coffee - the antioxidants are good for your brain.

                            The books suggestions was for her to write '50 Shades of Pain' as the story of my travails with my EM0480 grinder. And I was suggesting the OP make a video, so if he wants to include porn froth, I think that would be his choice.

                            Comment


                            • #44
                              Bow chikka, bow chikka chikki bow wow.

                              Comment


                              • #45
                                LLLaaadddiiieees and Ggggeeennnttttllleemen, its the moment youve been waiting for...

                                The problem has been solved!

                                How? A fresh descale using a new brand of descaler. The only solution we can draw is that the previous descaler, despite being one supposedly good in coffee machine must have caused the problem. It was a dissolvable descaler, as opposed to the new one, specifically dedigned for coffee machines which comes in a liquid form.
                                Our only guess was that the machine must have contained a significant amount of the original descaler, as many of you suggested.
                                The funny thing is that I did a test pouring steamed milk into a shot of water containing that descaler and I had to put in a disturbing concentration before the same curdling occured...so I dont want to think about what I was drinking out of that machine. Goodness knows how it managed to stay in the machine through so many coffees and flushings but the new descaler has fixed the issue instantly.

                                Thanks so much for everyones help and persistence, damn its great to have coffee back!!

                                Comment

                                Working...
                                X