La Pavoni soap bubbles every time I start foaming

[Word_salad]

Hopefully this hasn't been posted before

Every time I try to steam milk on my la pavoni I get huge soap bubbles right at the start. I've tried starting with the wand at different heights in the milk, but that doesn't seem to change anything. My boiler pressure is between 1.2-1.4bar, I make sure to purge the wand every time, and I am using a 1 hole steam tip. Also I am using oat milk if that makes a difference, though I have been able to steam this milk quite well on an HX machine.

Any advice?

[LObin]

That usually happens when steaming the first pitcher after warm up. I usually release steam for 10 seconds or so after warmup to prevent this from happening.

Which single hole steam tip do you use?
Europiccola or Professional?

You can also add a bit of corn starch to your oat milk for better texture, although it should steam just as good as it does on your HX.

[Word_salad (original poster)]

Wow I ran steam for 10s toady and that made a huge difference. No soap bubbles at the start. Still not perfect microfoam but I think that's a skill thing.

To answer your questions though, I have this wand tip for OE (https://www.orphanespresso.com/OE-SLIM- ... _2175.html), and i'ts a Professional

[Kaffee Bitte]

Oatmilk micro foam is annoying to get right. I have had good results by keeping the tip deeper and aiming for the quietest I can get it while keeping a vigorous swirl. Often to maintain the quiet I will be moving my steaming pitcher up and/or down a little to adjust. I usually stop it much earlier than I would for regular milk. Not above 140. 130ish is about perfect. Much higher temp at end will rapidly return large bubbles and ruin the microfoam.

[vit]

Wow I ran steam for 10s toady and that made a huge difference. No soap bubbles at the start. Still not perfect microfoam but I think that's a skill thing.

I have Bellman, which is a kind of similar size boiler. When there is no vacuum inside at the start, even more than 10 s is needed to purge most of air (20, maybe even 30 - depending how much above boiling point). I just put the tip into glass of water, so it's very obvious when big bubbles of air disappear and its mostly vapor inside, making much smaller bubbles. I usually wait until water in the glass gets a bit warm (while there is lots of air inside, there will be almost no heating of water in the glass) before deciding its purged enough

[LObin]

Wow I ran steam for 10s toady and that made a huge difference. No soap bubbles at the start. Still not perfect microfoam but I think that's a skill thing.

To answer your questions though, I have this wand tip for OE (https://www.orphanespresso.com/OE-SLIM- ... _2175.html), and i'ts a Professional

Happy I could help!

I believe it has something to do with trapped air inside the boiler but I'm not sure why this phenomenon is common on La Pavoni's but not on HX machines, even though they both have vacuum relief valves (on post-mills that is).

I've used the OE steam tip for a while and it's really good. You'll get the results your looking for soon enough

If you're ever looking for a solution to keep the brew water temperature down but steam at a higher pressure, shoot me a DM. I've done a pstat bypass mod on both my Professionals and it's really great.

Cheers!

[pizzigri]

Happy I could help!

I believe it has something to do with trapped air inside the boiler but I'm not sure why this phenomenon is common on La Pavoni's but not on HX machines, even though they both have vacuum relief valves (on post-mills that is).

Yes, it happens on post mil because the smaller piston in the vacuum relief valve assembly gets stuck so you get false pressure (air) in the boiler. Bleeding off false pressure will also yield better coffee! Reason this happens is sometimes due to scale, some other time the slight oxidation (blackening on the surface) makes the valve "sticky".
You should remove the valve Assembly and clean it out.

[Word_salad (original poster)]

Ah good to know, my machine is due for a cleaning anyway

Wait mine is a pre mil, would this still be the reason?

[pizzigri]

If your machine is pre mil and without an antivacuum valve, IMHO, then you HAVE to perform the purge maneuver to release false pressure (remove the air inside the boiler) to make good coffee and avoid the air bubbles in the milk when microfoaming. Do this when the machine is almost ready to brew.

Note that to upgrade your pressure release valve to an antivacuum configuration, you need to replace the whole valve body (including the part that fastens on the boiler) plus add the antivacuum valve itself and appropriate spring. If you do this, remember to also get the teflon gasket.
It is a worthwhile upgrade.