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  • Sunbeam EM6910 Screaming / Too Much Air In Milk

    I've read some old threads on this, but as it seems there can be a few variables to blame for this I'm starting my own.

    My daily two cups of bliss are being ruined by this issue at the moment and with a toddler and a houseload of builders to deal with at the moment I'm in real danger of chucking the blighter out of the window!

    I've cleaned, backflushed, soaked the wand tip in boiling water in detergent, poked all appropriate holes with the cleaning tools, run steam through the wand to try and clear any potential blockage. No difference.

    The machine was bought second hand in January but from a coffee machine retailer who had serviced / refurbed it. It came
    with the older style wand tip so I bought a new type and was impressed at the improvement in the microfoam.

    Nothing has changed in technique or type of milk used (top quality full cream local boutique type stuff). I've previously been getting good enough foam to produce passable amateur latte art.

    Confusingly I've read that both blockages and a steam nozzle that has gotten itself too wide or well cleaned can cause issues.

    Finally, I have the steam setting on hottest and wettest.

    At a loss now as to what to try next. I'm so dashed frustrated I could cry - my coffee keeps me sane and producing this...rubbish is killing me. Thoughts for next to try: -
    • Fiddle around with steam settings as I have also read here that different settings helped different machines.
    • Try my old steam wand tip on there to see if it behaves differently
    • Go and cut myself a sturdy branch and go John Cleese on the thing. Then claim insanity and make pretty eyes at husband till he sees the household budget can definitely stretch to a new one.


    Ideas would be so very much appreciated. I just bought a Mini Mazzer after months of saving and went through a month of frustration trying to get that to work right for me. I then got a grand total of about 5 "Oh YES" type coffees before the milk froth went to poo on me.

    I'm also too embarrassed to offer the poor builders a lovely hot beverage - I'm pretty sure they'd deliberately botch my bathroom if the microfoam was duff. Help

  • #2
    Does it scream only when stretching the milk? I was taught (and it is my experience also) that too little air, not too much, caused the high pitch squeal.

    There is a lot in your post, but what exactly is the problem?

    Comment


    • #3
      I was trying to pre-answer any questions, but sorry yes didn't describe the actual issue very well!

      Its happening about half way through the process. I have always managed to let in just enough air to get the micro foam just right with appropriate "chh chh" noises and so forth. Suddenly the milk is coming out incredibly over aerated and stiff like shaving cream. Lots of overly big bubbles even after giving the milk a wee swirl /polish.

      I'm getting that horrible noise that reminds me of my time working in cafes when I was a teenager. Very annoying.

      As I said my technique is unchanged and I've been getting what I consider to be jolly nice microfoam. Until now

      Comment


      • #4
        Just wanted to update the thread in case anyone finds this useful. I changed back to the old wand tip and suddenly it's all roses round the door again. Suggests what I read in other threads about it being an issue with the tip is right. Not sure if anyone has opinion about whether it being "too clean" is the problem? Or the nozzle widening a bit through wear?

        Anyhow I had a fab coffee with lovely latte art this morning

        Comment


        • #5
          Originally posted by Kirsty View Post
          Or the nozzle widening a bit through wear?
          Came here today due to the same problem, and your thread is the 2nd...

          The tip appeared to be "gunked up", even cleaning and soaking in vinegar didn't solve the problem. Bought a new tip and good milk texturing again.

          Comment


          • #6
            I had a problem with bubbles originally with my machine - found it very frustrating trying to keep the nozzle at just the right place to produce micro foam. For me, making the steam dryer helped quite a lot. Not sure if you want to muck around now you've got it working but I took mine back to Factory settings then reduced the wetness of the steam by 0.3 secs. I also increased the steam temp by (I think) 10º - not sure if it was 5 or 10 - was months back.

            I did this because I was getting what I thought was excessive dribbles as the steam came on.

            Comment


            • #7
              Seems these machines have steam tip issues at times!

              i will definitely experiment with the steam settings more but will wait till I'm making more coffees or have a chance to spend a happy afternoon experimenting. That way I will remember more about what I tried last!

              Comment


              • #8
                Remember to reset back to factory before experimenting. That way it is easier to keep track of what you are changing and by how much.

                Mind you, while I was posting I was running a full clean and descale - as I went to check the phone rang and I was delayed. When I went to turn off the steam there was a splutter and a couple of burps and suddenly my steam was MUCH louder. This is in spite of doing 6 or 7 cleans of the machine since Jan. Now I have to relearn how to make my microfoam - the steam is a lot more powerful and heats to optimum faster. I will be reverting to factory and finding out where my new settings should be.

                The water in the container was distinctly dark after the burps, whereas over the past few cleans it has been clear although sudsy from the descale. I figure something murky was lurking in my steam system and now it ain't.

                Comment


                • #9
                  Originally posted by Kirsty View Post
                  Seems these machines have steam tip issues at times!

                  i will definitely experiment with the steam settings more but will wait till I'm making more coffees or have a chance to spend a happy afternoon experimenting. That way I will remember more about what I tried last!
                  Hi Kirsty
                  The problem with Sunbeam steam wands is mostly due to the current insane influence of Occ Health and Safety in most things, including their manual.
                  Steam is approx 365 times the volume of water. The manual says to leave the steam wand in the milk so you do not splash yourself with near scalding milk. If you do this, you are slurping an unholy amount of milk up into the wand (not just the nozzle tip) every time you froth the milk. That is almost certainly the cause of your hassles (and virtually all newbie 6910 owners who believe the manual).

                  One friend with a 6910 steam problem: I had to take the whole wand off, soak it in Toluene overnight, hit it with two or three pipe cleaners and soak for another 12 hours and then the fourth or fifth pipe cleaner finally went through all the way. Possible thought: lactose acid may be neutralised by a base like bicarb soda – worth a try. Chemistry is not my strong point. I can tell you vinegar type solutions (i.e. almost every espresso machine cleaner out there) are almost useless. FWIW, I would not let Toluene in the same house as a child, even briefly. Even the fumes are kid-deadly. Methylated spirits may also work. The steam pump is actually quite well made, so perhaps Journeyman's “leave it running” may also be an option.

                  A quick test for cleanliness: get the lid of a takeaway container or similar that can fit / mostly seal a really large jug (say a litre+), cut a small hole in the top of the lid, just big enough to take the steam wand. Run steam into the jug until there is 20mm+ condensed water in the bottom of the jug. Turn the steam off and let it cool down to near room temp. Smell it. If you can smell anything at all, clean & test it again until you cannot smell anything at all. Then you can taste it (gingerly: it may still be truly awful). If you can taste anything at all, the wand is still in need of a clean. When I was in a hurry and a friend's 6910 needed a clean, I flushed the wand and immediately shoved a cleaning solution up to the nozzle so the negative pressure slurped a few ml of the cleaner up into the wand. I hesitate to recommend it as a fix, however it saved me the hassle of taking the whole wand out to clean it (it was pretty grim, there was coffee coloured gunk coming out of the wand). I then ran a lot of steam though it until it eventually ran clear.

                  My own 6910's wand (2010) has never needed more than an outside wipe clean and a quick flush. Why? Because I was taught to use a wand properly in 1979 as follows:
                  Quick Notes: This only applies to single hole nozzles. The four hole ones are faster, however it is almost impossible not to scald the milk slightly until you are an expert and will not need any instructions. Also, use a milk thermometer. Most good milk thermometers have a large dial with a red zone between 65 to 70 Celsius so half blind klutzes like me can see it without glasses. Mine cost $15 about a year ago. Cold milk and cold jug gives you more time to adjust the process at first. Also, feel free to look up any of the terms I use here online or ask via another post.
                  1. For a 500ml+ jug, flush & preheat the wand with a short burst of steam into the drip tray. If you see any colouration at all, stop and clean the wand again, as it still isn't clean. FWIW, for a smaller jug (I often use a 400ml one) I find it works a lot better if you do not preflush. That is probably sacrilege in barista circles, however I have found that frothing a really small amount of milk needs a gentler start.
                  2. Turn the steam on (probably full on for a clean 6910, they do vary). Froth the milk by creating a whirlpool as quickly as you can (look it up on the 6910 DVD or online). Tip: Have the top part of the steam wand contacting the jug “in the spout” and as sharp an angle as the wand will allow you (pointing around 60+ degrees on the 6910) with the nozzle as close as possible to the edge of the jug. Rationale: this gives the wand the lowest possible internal profile so you get the best possible milk circulation.
                  3. Start by “surfing” the top of the milk so you get a muted “sucking sound” (not my description, but it should do well enough). This is the stage to aerate the milk. Slowly lower the jug to maintain the sound. The goal is to aerate the milk as much as you can, as soon as you can. Then raise the jug so the circulation sound is almost non-existant for the next stage (which I think of as blending the foam). You may find backing the control off three or four settings may work better at this stage - experiment. The best latte froth is when the finishing stage is a relatively gentle blend / heat / circulate rather than aeration. That is the key to making quality microfoam in a 6910 as it makes the bubbles a lot smaller. Doing this well in a 6910 can give you true velvety (silky...satiny) microfoam at a standard beyond 90% of cafes.
                  4. Turn the steam off when it gets to xxx degrees. The trick is to allow for the temperature lag (most thermometers have a few seconds lag). A desired final temp of 68 to 70 Celsius for full cream cow milk is usually the best range. Most 6910's / milk thermometer combos have around a five degree lag, so shutting it off at around 63 to 65 should be close. Err on the side of cooler until you know your equipment, as scalded milk is undrinkable unless you are a smoker (a ten times higher taste threshold can hide a multitude of evils). Unfortunately, you only get top quality “velvet” microfoam just before the milk scalds (approx 70-71 for full cream cow milk).
                  5. As soon as the sound of the steam pressure drops in pitch remove the wand along the line in the jug (i.e. about 60 degrees angle in a 6910). The concept is to disrupt the still swirling froth as little as possible, and to do it so the pressure drops to zero just after the nozzle is clear of the surface of the foam. Trust me, if you get the “withdrawal line” correct even full steam pressure will not splash you, however it will totally wreck the microfoam by blasting air into it just when you (hopefully) got it correct.
                  6. Wipe the outside of the wand down immediately while using a clean cloth whilst realigning the wand over the drip tray.
                  7. Turn the steam back on for a second or two. If the steam is not clean / clear on the drip tray (i.e. not the slightest trace of milk, white / brown or anything else) then there is more initial cleaning to be done. Or you did not pull the wand out fast enough and you need to clean & flush the wand thoroughly (again). FWIW, I use a cut in half chuxwipe for this, as the texture seems to help clean it more quickly than most alternatives whilst the reduced size is easier to handle.




                  A quick test of your microfoam: First, it should have a silky sheen to the milk when you hold it so it reflects against a light source. It should pour a little more slowly than normal milk but very cleanly out of the jug. No clinging to the sides. Any residual which will not pour out should be minuscule. If you need to spoon it out, it is wrong. If you really think you have it perfect, put any fine grained pattern into the eventual latte and leave it for an hour or so. If the microfoam is correct, the “white” pattern will be unchanged. If the brown is also unchanged, you got the coffee spot on as well. Then feel free to kick yourself for not drinking it whilst simultaneously having the warm glow of satisfaction that you really nailed it to best barista standard...



                  I hope this helps, as using the above technique has meant I only have to clean the wand once for said friends and never again. It also improves their microfoam (sometimes massively) in the process.
                  Then you can treat your renovators to an amazing cuppa and earn their undying gratitude (well, for the next day when they line up again for another fix).

                  Comment


                  • #10
                    Sorry, I forgot to add that older 6910's are usually best at the factory setting when they are totally clean. Newer 6910's tend to vary, so use a fast reading digital thermometer to see what the temperature really is set to. Drier steam usually gives far better microfoam in a clean 6910. Refer to my long posts to Journeyman in “My New Machine” to work out which you have. Warning: Some idiots out there are “repairing” 6910's by mixing up new and old parts. I have seen a whole pile of hybrids out there.

                    Comment


                    • #11
                      Originally posted by TampIt View Post
                      If you do this, you are slurping an unholy amount of milk up into the wand (not just the nozzle tip) every time you froth the milk.
                      Morning Tampit, welcome to CoffeeSnobs.


                      While I agree with most of your post I find the above quote a little odd, if the machine did in fact "slurp up an unholy amount of milk" the result would be a contaminated boiler.

                      Milk cant be drawn up into the steam wand while the steam is flowing (positive pressure) I imagine if you left the tip in the milk whilst is was cooling a vacuum may occur and some may be drawn up into the wand, and if you were silly enough to exhaust the steam then leave the tap open with the wand in milk/water and turn the unit off you may well achieve a similar result i.e. contaminated boiler.

                      However if you follow normal hygiene practices, i.e purge with steam, wipe, blow out, tap off, you should never have a problem.

                      Comment


                      • #12
                        Thanks to everyone who has taken the time to respond to my post - I appreciate the help and extensive information very, very much. There's lots there for me to pay attention to and absorb. I'm sure I'll be trouble free about the wand tip department in no time. Meanwhile I got impatient and bought a new tip. The $26 is worth a return to consistency as I'm often time poor and the opportunity for coffee is a small window in my day.

                        Particularly liked the detailed milk texturing tips - so so useful for me. I like to try and improve all the time as I'm rarely 100% happy with my efforts

                        Next time I achieve babysitter I'll work away at getting the old tip back to normal function. I've always been very fussy about purging and wiping it after use so this is frustrating.

                        Thanks again all

                        Comment


                        • #13
                          @yelta: I think what he is getting at is the recommendatio to leave the tip of wand in the milk until AFTER steam stops.which woul get close to the situation you mention; no steam.
                          In my case I had run a cleaning regimen regularly & only when I inadvertently left the steam on did I find out what is possible fro. A 6910 wand.

                          Comment


                          • #14
                            Originally posted by Journeyman View Post
                            @yelta: I think what he is getting at is the recommendatio to leave the tip of wand in the milk until AFTER steam stops.which woul get close to the situation you mention; no steam.
                            In my case I had run a cleaning regimen regularly & only when I inadvertently left the steam on did I find out what is possible fro. A 6910 wand.
                            Surely he is not suggesting to leave the steam on while you lift the wand out? That's a great way to make a mess of your milk and your bench.

                            Comment


                            • #15
                              Originally posted by Yelta View Post
                              Morning Tampit, welcome to CoffeeSnobs.


                              While I agree with most of your post I find the above quote a little odd, if the machine did in fact "slurp up an unholy amount of milk" the result would be a contaminated boiler.

                              Milk cant be drawn up into the steam wand while the steam is flowing (positive pressure) I imagine if you left the tip in the milk whilst is was cooling a vacuum may occur and some may be drawn up into the wand, and if you were silly enough to exhaust the steam then leave the tap open with the wand in milk/water and turn the unit off you may well achieve a similar result i.e. contaminated boiler.

                              However if you follow normal hygiene practices, i.e purge with steam, wipe, blow out, tap off, you should never have a problem.
                              Hi Yelta



                              Thanks for the welcome, browsing CS has been fascinating.

                              I tried to simplify my earlier post down to a novel. A more complete answer for that part is below for a 6910 only.
                              The "slurp up an unholy amount of milk" is exactly what happens if you follow the Sunbeam manual to the letter (third sentence in my post). The nozzle will be fully buried in the milk and it causes a strong vacuum “quite rapidly”. Testing it with water today, it is well under a second. I have no desire to pollute my own 6910's by testing with milk... Using my USB microscope, my own machine has nothing visible in the lower reaches of the wand – it literally looks like a clean, fresh metal surface and I intend to keep it that way.

                              A bit of background: the 6910 has a “relatively enormous, high thermal mass” stainless steel thermoblock for the coffee (easily big enough to generate a large double without a temperature or pressure drop) and a fairly large stainless steel milk thermoblock. Most other (cheap) thermoblock machines use all sorts of metals in single much smaller, lower thermal mass thermoblocks. Whether thermoblocks can create more of a vacuum that way than a boiler I do not know, I would guess that it is roughly equal (with no data at all to support that thought). Probably not relevant as no knowledgeable espresso person in their right mind would leave the wand in the milk after turning the steam off anyway.
                              Back to the issue: If you leave the tip in the milk for too long after after turning the steam off it is actually forced up into the wand. I tried this today using 70 Celsius water in the jug, and managed to get around 5ml into the wand. I recognise that it is hard to measure that way as some recondensed steam from the unit itself would also be present, so that is an approximate differential measurement. Also obvious, milk will behave differently from water. I know from various other 6910's they can slurp up enough milk to get close to the "straight top" of the S-shaped steam wand - which is about 30mm from the swivel. That is also approximately 5ml volume, so my measuring / guesstimate seems “in the ballpark”. Several of my friends have achieved that “distinction” when their 6910 steaming failed. The critical issue is that it is still a long distance from the thermoblock. I fully agree that if it could go further "up the wand", it would eventually get to the stainless thermoblock. I do not believe that it can do so, as the milk always starts at the nozzle each time.

                              What else it could do to a stainless thermoblock is debatable, as milk has no effect on stainless at normal temperature and pressure. I have no idea at all whether the temperature and pressure inside a stainless thermoblock would change that. If it was a boiler – you are correct: probably destruction, certainly problems. FWIW, that and other “operating with due ignorance” factors are just possibly the main reasons why many domestic users so readily kill boiler-type domestic machines. That is if tap water is not the culprit. A two week old La Cimbali had enough corrosion to cause a total fail in two weeks in a Perth suburb called Osborne park a few years ago. The tap water there at that time could probably have been used as sheet metal or sewerage depending upon your need...

                              Anyhow, this is how I think it actually works in a 6910 if you follow their (resisting resisting resisting.. temptation to call it their destructions) instructions:-
                              If you leave the wand in the milk and turn the steam off, the temperature and pressure inside the wand will drop rapidly. As soon as the steam reconverts to water (i.e. the 365 to 1 volume reduction) it creates a vacuum which will pull the “near 70 Celsius” milk up into the wand.
                              Milk breaks down around 70 Celsius, and the best microfoam is a fraction short of breakdown. That means any additional heat will instantly break the milk down, forming a variety of solids suspended in a thin watery fluid (“curds & whey”???).
                              To continue, about 5ml of milk heads up the wand. The wand's metal is still hot enough to break down and then “contact dry” the solids in the milk almost instantly due to the large surface area to volume ratio inside the wand. This will form a solid crust around the inner surface of the wand (just like I have seen too often). The wand could also act as a capillary tube to some extent or another which may have a bit of involvement. If you don't flush it promptly (maybe milliseconds) it is too late. The spiral of death commences. I have never left the wand in when I am frothing milk so I really do not know how big the time window for flushing really is other than my earlier “less than a second”.

                              Another issue, the 6910 wand has a lot of thermal mass as it is a lot heavier than virtually any domestic machine. It is also nearly twice the weight of my La Pav, and most other commercial machines. At a guess, that may be necessary to smooth out the flow temperature and pressure of a dedicated thermoblock. Regardless, more thermal mass=more ability to retain the heat, which would add to what I now think of as “sucking time”.
                              The next time you use the unit, the existing crust will have altered the pressure and the area available for the next lot of milk to go through. Inconsistent frothing is the result at first, until the buildup is severe enough to need major corrective surgery.
                              Amazing to think that one stupid line in a manual can cause all that havoc, isn't it?

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