Hi,

I'm curious about why some machines have so visual steam when others almost invisible?
my 10+L Aurora have an almost invisible steam, but in the garage I have another HX machine with a 3.5L boiler and the steam is VERY visible..
Do the size of the boiler have something to do with this or is something else?

sore of a useless info, but I WANT TO KNOW..

Juanjo

Is it colder in the garage?

sort of useless info, but I WANT TO KNOW..

And so, how much are you willing to pay? The moisture content of the steam has a lot to with visibility. As moisture content goes up, so does visibility. Higher boiler water levels increase the likelihood of "carryover" of water which (obviously) increases the moisture content and some high-end machines APPEAR to have water separators (of sorts) where the steam line is attached to the boiler and thus the steam is drier and less visible.

Thanks,
both very good points..
wish the "little" machine in the garage was a bit lighter to bring it to the apt and see if at the same room temperature there is any change..

but if there is a change or not, after I figure it out I'll have some useless information in my head, and a damn heavy machine in the living-room, which I'll have to carry down again..

thanks again..

Juanjo wrote: wish the "little" machine in the garage was a bit lighter to bring it to the apt and see if at the same room temperature there is any change..

Sheesh, Juanjo, the solution is to open the windows until the apartment is the same temp as the garage! ; >

At least it'll start to warm up pretty rapidly once the steam experiment starts...

erics wrote:And so, how much are you willing to pay? The moisture content of the steam has a lot to with visibility. As moisture content goes up, so does visibility. Higher boiler water levels increase the likelihood of "carryover" of water which (obviously) increases the moisture content and some high-end machines APPEAR to have water separators (of sorts) where the steam line is attached to the boiler and thus the steam is drier and less visible.

Sorry kids, but steam is invisible and the only gas coming from the boiler thru the steam wand of a HX machine that is operating correctly is water vapor. If you see anything, then you see condensed water droplets, which ARE visible (think cloud here). Sources of condensed water include condensed steam due to relatively cold surfaces and water droplets entrained in the steam, if the water level is excessively high in the boiler. FWIW,the steam in the boiler is saturated at high pressure (1.1 or 1.2 bar prolly for a HX), so the temperature is around 250F. Once the steam valve wetted surfaces and steam wand are sufficiently heated, the steam is superheated when it expands to atmospheric pressure, which is why you don't see condensation near the tip. The answer to the OP's question is that the degree of superheating, and therefore how close to the tip condensation occurs, depends on how hot the internal components in the steam path become, and how much steam is produced by the machine. An Aurelia produces lots of steam.

-Greg

Here are a couple of other thoughts. Steam, in the Engineering world is an invisible gas. In the everyday sense we consider steam the stuff that comes out of the teapot while whistling. The steam boiler is a very interesting piece in the espresso machine. While it is just sitting there, the contents are just water (on the bottom) and steam (on the top). It is a very low quality steam because of how much water is contained in the steam. It is still invisible, but it is like an August day in Virginia inside the boiler. When the steam valve is opened, the pressure has a sudden drop in the boiler and the water begins to boil, the temp drops also, and water begins to condensate out of the steam. Additionally, if the steam is going through cold tubes and valves, it cools further causing more water to condense in the steam. As you leave the steam valve on the steam heats the parts, the heating element comes on and the boiler comes close to a steady state condition (i.e. not as violent boiling, less water condensating out of the steam etc.). So maybe sometimes you have noticed as you leave the steam valve on longer it tends to get a bit "less watery". This happens because of both conditions above.
One other cause is the position of the steam exit from the boiler. When the water boils it can actually send bubbles to the outlet of the steam. Also if the boiler contains any sediment, the water can also foam causing more bubbles to exit (kind of like when you are cooking rice and start to watch TV and forget to turn the stove down).
The last condition is the ambient air. The colder the air is outside the machine the less of an ability it has to absorb water. Just like your breath on a cold day. As the steam exits, less of the condensed water will absorb into the air. The humidity also has some effect much like temperature.

Bill C

Greg and Bill,
I got more than what I was bargaining for ..
thanks a lot!

since my Aurora is feeling needy, with the help of wife brought the other machine up..
as far as I remember the steam is more visible than the Aurora, but a little less visible than when it was in the garage.
to bad I can't try both at the same time..

thanks again,