I'm far from expert on milk steaming, but I can share a bit of my experience.
From my experience, too much/strong of a whirlpool caused whipping action (just like using electric mixer).
When I reduce the whirl power, it stopped happening. When I go full on (3 o' clock on milk pitcher w/ full swirl), volume keeps adding, especially when temp get warmer.

As soon as I move more towards the center (just 1/4 of the way), it stopped happening, and I had better microfoam.

Try it out!

Thanks for all the tips!

Just thought it was a little weird, that it seems like this does happen to others, and yet I've never seen a tutorial saying anything about this, or the possible solutions.

Cheers

Not sure if it was mentioned but the room temp air you suck into the milk expands about 11% when it's 130F.

My GS/3 put 28g of water in 250g of milk steamed to 130F. Not sure how that compares to other machines but that's a 11% volume/weight increase.


I've got a 60 gallon steam kettle at work and for it to work properly, you have to put it into a vacuum state. You do so by heating it up and venting off some of the steam, very similar to steaming some milk. Hmmmm. But I don't think our steam boilers stay under vacuum. Interesting thoughts though.

This is well known in cafes. People sometimes order "Extra extra hot lattes, no foam." And they will send it back if it isn't hot enough.

You have to explain to them that at a certain temperature it is impossible to have little foam. It will create larger than microfoam air bubbles regardless if you let in only one little sip of air in the beginning.

I never thought about why, but my assumption is that the bubbles are air and when air gets hotter it expands, increasing the volume. Pretty simple.

2710.89 J/g (h of Sat.Steam at 1.2bar)
4.18 J/g.K (Specific heat of water, ~milk which is mostly water)
Tdiff = 66K (from 4*C to 70*C)

--> ~0.10g steam per g of milk needed (1g steam --> 1ml water when condensed)

which is ~10% increase in volume of liquid in the end result (1g + 0.1g = 1.10g)

My guess is this is where that metric comes from.

I know this thread is a month old, but just saw it now and have something to add.

I had the same experience you described after upgrading to an ECM Synchronika from a La Spaziale Mini Vivaldi II. I tried different tip locations and pitcher tilt angles with only slight improvement in my success rate. But after a while I started focusing my attention more on the roll I was achieving than the position I was holding my steam wand. I discovered that there are different patterns and strengths of rolls that I could achieve. Some seem to draw in additional air during the texturing phase and others don't. Now that I know what to look for, my success rate is much higher.

I also plan to buy a different pitcher for latte art purposes, and will be interested to see if the different size/shape also affects my milk steaming results. If it's an improvement, great. If it's worse, I can always steam in my current pitcher and transfer to the other for pouring.

Don't worry. You're fine!

I use a 50cl pitcher. It takes my machine about 20-25 seconds to fully prepare the milk for pouring. Of that time, I only spend about 2 to 3 seconds on phase 1 (aerating) and the rest of the time in phase 2 (rolling or texturizing). The milk is still cool to the touch when I start texturizing.

Don't forget, the steam wand blows plenty of air too. You have to know your particular machine. There's no universal rule that says you have to aerate for a certain amount of time or until the milk is a certain temperature. You have to observe and adapt to your particular machine. There are too many variables to go by other people's formulas (steam pressure, steam volume, boiler type, number of holes in tip, size of holes, orientation of holes, type and shape of pitcher, type of milk, etc.

The other factor may be your technique. The milk has to roll when the steam tip is submerged. Otherwise, you're not breaking down the bubbles and simply making the milk more foamy.

Good luck

My friend had a Motta pitcher which I tried last week. Night and day from my generic pitcher. I ordered one - got it today.