Results 1 to 12 of 12

Thread: Milk drawn into boiler

  1. #1
    Senior Member FineGrind's Avatar
    Join Date
    Jul 2012
    Posts
    116

    Milk drawn into boiler

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    How easy or hard is it to get milk sucked up into the boiler if you forget to purge the steam wand before and after steaming milk? It worries me.

  2. #2
    Senior Member Bernsbrew's Avatar
    Join Date
    Jun 2012
    Location
    Lane Cove, Sydney
    Posts
    137
    I can't see how this would be possible with positive pressure in the boiler, can a boiler develop a vacuum?

  3. #3
    Senior Member Vinitasse's Avatar
    Join Date
    Aug 2010
    Location
    Mornington Peninsula VIC
    Posts
    1,251
    Wouldn't negative pressure develop as the boiler cools? And, if there happened to be a bit of milk inside the steam wand, isn't it possible it could be drawn into the boiler as it cools after shutdown?

  4. #4
    Senior Member Bernsbrew's Avatar
    Join Date
    Jun 2012
    Location
    Lane Cove, Sydney
    Posts
    137
    You've got me worried now. Where are the engineers and physicists when you need them?

  5. #5
    Site Sponsor coffee_machinist's Avatar
    Join Date
    Jun 2011
    Posts
    683
    Very unlikely, unless your anti-vac valve is stuck, the machine cools down and you leave the wand sitting in a jug of milk all day, then open the steam valve (yes, I've seen it done).

  6. #6
    Senior Member Bernsbrew's Avatar
    Join Date
    Jun 2012
    Location
    Lane Cove, Sydney
    Posts
    137
    Anti-vac valve, is that what is sometimes referred to as a downstream valve? Also, if this valve does stick, wouldn't the boiler implode, since a boiler is only designed to withstand positive internal pressure?

  7. #7
    Senior Member Vinitasse's Avatar
    Join Date
    Aug 2010
    Location
    Mornington Peninsula VIC
    Posts
    1,251
    Quote Originally Posted by Bernsbrew View Post
    Anti-vac valve, is that what is sometimes referred to as a downstream valve? Also, if this valve does stick, wouldn't the boiler implode, since a boiler is only designed to withstand positive internal pressure?

    Boilers do implode every once in a while. Rapid cooling without pressure equalization (i.e. opening up the steam valve) has lead to the loss of more than a few boilers over the years. Although, this does not seem to be as much of an issue with newer machines. Superior boiler design perhaps?

  8. #8
    Senior Member Pavoniboy's Avatar
    Join Date
    Jan 2009
    Location
    Minnamurra NSW
    Posts
    693
    I would imagine not very difficult once the anti-vac valve is stuck. I say this as I bought an old commercial HX which had milk taint in the boiler. I had seen the owner use it and leaving wand in jug of milk etc was not what he did, however purging wasn't done either. Once home and and the machine properly assessed, the anti-vac valve was stuck and the steam coming out of the boiler was foul - very 'off-milk' taint to it which made any steamed milk undrinkable.

    I am confident that this machine became tainted due to anti-vac being stuck for some time and the wand not being purged so all it takes is someone to open the steam valve when cold, or the steam valve not sealing properly and that milk makes its way back to the boiler.

    I not only purge the wand religiously, but I also listen as my machine comes to boil to make sure that anti-vac valve is still working.

  9. #9
    Senior Member
    Join Date
    Jul 2012
    Posts
    700
    Would be more related to machine malfunction than user error on a newer machine.

  10. #10
    Senior Member trentski's Avatar
    Join Date
    Nov 2009
    Location
    Altona, Melbourne
    Posts
    1,578
    There are fairly regular threads where people have milk taint in their boilers. I always make sure that I clean and purge the steam wand whenever I make a milk drink, it's just good hygiene

  11. #11
    Senior Member
    Join Date
    Jul 2012
    Posts
    164
    Do you guys steam a jug of water after each use? I was told to do this. It only takes about 15 seconds and you see all the milk particles in the water even after purging. If anyone didn't steam the jug of water that would become stuck inside the steam wand and eventually go off..

    This would also avoid someone leaving the wand in a jug of milk etc. It's just a habbit I now obtain and I guess it just works.

  12. #12
    Senior Member Vinitasse's Avatar
    Join Date
    Aug 2010
    Location
    Mornington Peninsula VIC
    Posts
    1,251
    Behmor Brazen - $249 - Free Freight
    Quote Originally Posted by neofelis View Post
    Do you guys steam a jug of water after each use? I was told to do this. It only takes about 15 seconds and you see all the milk particles in the water even after purging. If anyone didn't steam the jug of water that would become stuck inside the steam wand and eventually go off..

    This would also avoid someone leaving the wand in a jug of milk etc. It's just a habbit I now obtain and I guess it just works.
    Steaming a jug of water is more about cleaning the outside of the wand. As for any milk inside the wand, that would have been forced out pretty quickly with the first few blasts of steam.



Similar Threads

  1. Does steaming milk negatively affect the nutritional value of milk?
    By Dragunov21 in forum Milk Froth and Bubbles
    Replies: 59
    Last Post: 27th October 2013, 08:40 PM
  2. Please advice on Full Cream Milk and Skinny Milk
    By raja_kopi in forum Milk Froth and Bubbles
    Replies: 4
    Last Post: 31st August 2011, 01:40 PM
  3. Replies: 5
    Last Post: 28th June 2011, 06:40 PM
  4. Smallest boiler for great milk
    By dane5431 in forum Brewing Equipment - Midrange ($500-$1500)
    Replies: 0
    Last Post: 11th May 2011, 12:49 PM
  5. Milk taint in boiler
    By Dimal in forum Brewing Equipment - Extreme Machines ($3000+)
    Replies: 0
    Last Post: 15th June 2007, 10:33 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •