Milk Steaming

[Moon]

Thanks everyone for your advice all those weeks ago. After much consideration I've bought a Office Leva Dual Boiler and a Eureka Mignon grinder.

I'm very happy so far - I do enjoy the coffee making process :)

Only regret so far is that it's not plumbed in - I'm forever lifting the lid to fill it. Not such a big deal, but means I can't fill it whilst warming my cups, and also exposes the less beautiful inside of the machine.

A question about the steam wand though - when the milk is cold I put the wand deep in the milk and turn the tap... and get a banshee like screaming that sends the poor cats fleeing. It passes after 10 seconds or so, and can be prevented if I turn the tap on with just 0.5cm of the tip in the milk.
What causes this?

[Glenn]

A very unscientific answer follows;
When you have a blown up balloon and you release the air it makes a whooshing sound
Blow the balloon back up but this time restrict the size of the outlet. The air escaping emits a high pitched sound as it is creating pressure to escape

As the air is lighter (less dense) than the liquid it is wanting to escape and is being forced up through tiny vents in the milk, causing the screaming sound
As the milk heats up (hot air is introduced) the screaming will disappear as the liquid is less dense, and will now volumise (larger pockets of air and liquids)

The screaming comes back when the milk is too hot. Possibly as there is no more room for expansion and the milk is collapsing (back to a water state)

I'm sure someone will have the technical/scientific reason...

Start by placing the steam wand tip just below the surface so that steam is introduced. Bubbles will form and the milk should be swirling around the jug at this point.
Plunge when the milk is about 30c and keep the milk moving. No screaming.
Stop steaming at approx 65c

Hope this helps

[lookseehear]

Congrats on the purchase, we want pics!

Where did you buy it from if you don't mind me asking as BB don't seem to have them in stock at the moment.

[ChiarasDad]

There are some very nice training videos at Metropolis Coffee University (http://www.metropoliscoffee.com/university/training/), covering their practices for latte steaming, cappuccino steaming, and latte art.

[sandykt]

How big is the water tank on the Office Leva? Congratulations on your new toys.

Lets see some pictures!!

[BanishInstant]

Just checking that you first open the steam valve into the drip tray to catch the initial water droplets. Briefly switch off and then plunge into milk prior to switching back on again.

[mike 100]

can anyone advise me on getting decent microfoam on an ascaso dream- fitted with a panarello tip, which does pull off,but leaves the wand a bit short, is there an optimum outlet size? the outlet on the panarello is 10mm I wondered if a smaller bore would be benificial ?

Regards

[Omaristalis]

If you steam a jug of water instead of milk, it will scream and scream until done, because the sound of the steam exiting the wand and condensing in the water is transmitted straight throught the water to the jug without anything to absorb it.

When you steam milk, you will get the same effect if you steamed it without adding any air to the mix - i.e. kept the wand at the bottom of the jug. As soon as you start to introduce air, I believe the little air bubbles act as insulation, absorbing the noise from the wand and making everything quiet again.

You really want to start getting some air in there as soon as you can after turning the steam wand on, because the later you leave it (and therefore the hotter the milk is), the harder it is to whip that air into the milk, giving you big bubbles.

[Moon]

Thanks everyone. Curiosity assuaged!

I'll dig out my camera on the weekend and share the joy :)

lookseeehear: I got the last one in stock from BellaBarista sorry!

sandykt: It's got a 2.8L tank - a decent size, but I find myself using water for more than just coffee and steam... cleaning the shower, heating the basket if I need to swap between single & double, rinsing the portafilter and ginger tea for she who must be obeyed. (My first name is Sandy btw!)

[Glenn]

Just thought I would post a picture to show that you can get decent milk from a stock standard steam wand (in this case on a Gaggia Classic - with no modification at all)

http://twitpic.com/show/thumb/3fabz2.jpg

Larger image here (http://twitpic.com/3fabz2)

[DonRJ]

Show off:)

[Glenn]

It's a poor pour but proof that it can be done at least.

[Eyedee]

I have envy!!!!

[standard issue]

Just thought I would post a picture to show that you can get decent milk from a stock standard steam wand (in this case on a Gaggia Classic - with no modification at all)

http://twitpic.com/show/thumb/3fabz2.jpg

Larger image here (http://twitpic.com/3fabz2)

Show-off!!!

[davey]

wish I could get decent microfoam enough to do that on my gaggia classic, I have the rancillo steam wand modification too!

[DonRJ]

I get lovely microfoam, just spectacularly useless at creating anything vaguely artistic with it.

[BanishInstant]

Don, you need the supersized Wand modification to get the best microfoam - it takes up half of the kitchen ;)