Commercial Espresso Machine - Average Steam Pressure

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Simon345

#1: Post by Simon345 »

Question for people that have experience with commercial grade espresso machines.

What do you think is the average (or most common) steam boiler pressure that you have seen?

lain2097

#2: Post by lain2097 »

Most I've seen and used. 1.1-1.2bar

Though that's with a mechanical pressure stat and because 99% would assume HX, that greatly affects brew temperature

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#3: Post by another_jim »

1.0 to 1.25 is the most common range. The steam boilers on older LM dual boilers went as high as 1.75 - 2 bar to store more energy and provide quicker steaming (not sure if this was a Starbucks special, or if it is still the case). Some lever machines run from 0.75 to 1.0, especially if they were sippers directly bolted to the boiler.
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Teflon1064

#4: Post by Teflon1064 »

The Sirai pressurestats used on most commercial HXs are shipped with a range of 1.0 to 1.2 bar. This seems to be the most common range used. If the pressurestat is getting old and inflexible the deadband can increase to 0.4 bar or more.

Simon345 (original poster)

#5: Post by Simon345 (original poster) »

Thanks for the advice!

I would love to understand what influences the 'steam power' of a given espresso machine.

For example I could get the same steam tip on 2 different espresso machines, and 1 would team a pitcher of milk in 10 seconds and the other machine would do it in 30 seconds.

Is this simply a function of the steam boiler pressure, and whichever machine has the greater boiler pressure wins?

DeGaulle

#6: Post by DeGaulle »

At a given diameter of the holes of your tip the flow of steam is more or less proportional to the absolute pressure (your gauge pressure plus the ambient pressure, which is about 1 bar at sea level). It is the combination of steam pressure and boiler volume that determines the endurance of the.machine as a steamer. The more water the boiler holds, the larger the heat buffer it provides for prolonged steam generation without losing too much pressure, assuming that the heating element can keep up. Most prosumer machines have a heater rated for 1200 -1400 watts.
Also there is the matter of horizontal vs. Vertical boiler that could play a role. A horizontal boiler provides a larger water/steam interface area, larger head space, so you may have less entrainment of water droplets.
Bert

Simon345 (original poster)

#7: Post by Simon345 (original poster) »

As an example of what I am trying to calculate:

When I look at the video's of people steaming with a Linea Mini they seem to complete the steaming task of a pitcher of milk very very quickly. So would I expect that if I use the same steam tip as a Linea Mini with the same 1.2 Bar (or whatever) that the Linea mini steam boiler is set to on an alternative prosumer machine (Profitec, ECM, Rocket etc..), that I would steam the same pitcher of milk in the same amount of time?

Why/Why not?

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DeGaulle

#8: Post by DeGaulle »

The Linea Mini has a larger steam boiler than typical prosumer machines (3.5 liters vs. approx. 2 liters). Assuming a tip with the same number of holes with the same diameter, a smaller boiler results in a more notable decline of steam pressure and therefore decline of steam flow rate while you steam. This is not necessarily a problem, because the stretching of the milk in the early phase requires the highest steam velocity and therefore the higher pressure to suck in the air. As you further heat up the milk, the pressure declines. This only means that the rate of heating up declines, therefore it takes longer to get to the desired 65 degrees C / 150 degrees F in comparison to a larger steam boiler.

Having worked with a LM Linea Classic as well as a Kees vd Westen Spirit on a few training occasions, I noticed that the steam pressure on these commercial machines was set substantially higher than the 1.2 bar gauge usually applied on prosumers, judging by the velocity at which the water and steam exited when purging. With the Spirit, when I purged the steam wand, some condensate hit my knuckles and I noticed that the small wounds inflicted weren't so much burn marks, but mere impact wounds from the water spray.
Bert

kwantfm

#9: Post by kwantfm »

Steam pressure on my Linea Mini is running at 2 bar.
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JohnB.
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#10: Post by JohnB. »

DeGaulle wrote: Having worked with a LM Linea Classic as well as a Kees vd Westen Spirit on a few training occasions, I noticed that the steam pressure on these commercial machines was set substantially higher than the 1.2 bar gauge usually applied on prosumers, judging by the velocity at which the water and steam exited when purging. With the Spirit, when I purged the steam wand, some condensate hit my knuckles and I noticed that the small wounds inflicted weren't so much burn marks, but mere impact wounds from the water spray.
The Speedster & Spirit ship with a 2.3 bar steam boiler setting. I've tried a number of lower settings but always revert back to the 2.3 bar default.
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