# Purging the steam wand



## Padder (Dec 14, 2012)

Like everyone (I'm pretty sure), I diligently purge the water out of my steam wand before frothing but continually ask myself why? As milk is (according to google) between 85 and 95% water anyway, what is the point in avoiding introducing a tiny amount more? Is it down to the water in the wand maybe being stale or is there some more scientific reason for it? I'm sure if there is that someone on here will know it and put my mind at rest that I'm not wasting a precious couple of seconds on a regular basis


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## Mrboots2u (May 10, 2013)

I used to do it , to avoid putting water , as opposed to steam in my milk . Come on you can spare those seconds making a cuppa can't you


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## garydyke1 (Mar 9, 2011)

You said froth









Just heat and wet your milk cloth with the purge and its two birds one stone , not a waste of time.

Hope you're purging after steaming too


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## Padder (Dec 14, 2012)

garydyke1 said:


> You said froth
> 
> 
> 
> ...


Yes, always purge pre and post steaming but still no one can give me a scientific reason. Is it just one of those things we do because we have always done it that way?


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## Mocochoco (Dec 26, 2016)

It's simply to remove water that has built up in the steam wand. It's not going to make a huge difference but why inject unnecessary water which could affect the consistency and also the precious few seconds texturing the milk.

Also helps in case it wasn't sufficiently purged the last time by someone else.


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## eusty (Dec 6, 2016)

Mocochoco said:


> It's simply to remove water that has built up in the steam wand.


I've noticed that if you don't purge then the first few seconds injecting water can cause large bubbles in the milk due to the water.


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## garydyke1 (Mar 9, 2011)

Padder said:


> Yes, always purge pre and post steaming but still no one can give me a scientific reason. Is it just one of those things we do because we have always done it that way?


We do it because we don't want residual water from inside the wand to be deposited into the milk, when we start steaming we want fresh hot DRY steam with full steam power right from the start not a second or two of sputtering creating larger bubbles.

We purge afterwards to ensure no milk ends up being sucked back into the wand and clear the holes in the steam tip.


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## Padder (Dec 14, 2012)

garydyke1 said:


> We do it because we don't want residual water from inside the wand to be deposited into the milk, when we start steaming we want fresh hot DRY steam with full steam power right from the start not a second or two of sputtering creating larger bubbles.
> 
> We purge afterwards to ensure no milk ends up being sucked back into the wand and clear the holes in the steam tip.


Yes, I fully understand the reason to purge after the milk has been steamed and think that the main reason to do it beforehand is actually to make sure the wand is properly cleaned. A few seconds of superheated steam should kill anything in there. Anyway, I'll continue to do it before and after steaming


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## mremanxx (Dec 30, 2014)

As my mum used to say "just because"











Padder said:


> Yes, I fully understand the reason to purge after the milk has been steamed and think that the main reason to do it beforehand is actually to make sure the wand is properly cleaned. A few seconds of superheated steam should kill anything in there. Anyway, I'll continue to do it before and after steaming


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## Grimley (Jan 18, 2015)

Dunno if this is true, but I read somewhere on the internet that if you don't purge the wand after steaming, what milk & water remains in the wand as it cools siphons that liquid back into the boiler. The milk will go bad & may make the boiler stink.


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## MediumRoastSteam (Jul 7, 2015)

Padder said:


> Yes, I fully understand the reason to purge after the milk has been steamed and think that the main reason to do it beforehand is actually to make sure the wand is properly cleaned. A few seconds of superheated steam should kill anything in there. Anyway, I'll continue to do it before and after steaming


If I don't purge my steam wand before hand, there is quite a bit of [visible] condensation which comes out (I think I measured once, something like 10ml?). I purge it until there is no more.

PS: I can measure again tomorrow if is of interest.


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## Padder (Dec 14, 2012)

pessutojr said:


> If I don't purge my steam wand before hand, there is quite a bit of [visible] condensation which comes out (I think I measured once, something like 10ml?). I purge it until there is no more.
> 
> PS: I can measure again tomorrow if is of interest.


Interesting. I don't get any water out of mine but the steam looks different for the first second or two which I presume is moisture of some kind. No need to measure yours but I wonder if different machines and household conditions make a difference


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## MediumRoastSteam (Jul 7, 2015)

Padder said:


> Interesting. I don't get any water out of mine but the steam looks different for the first second or two which I presume is moisture of some kind. No need to measure yours but I wonder if different machines and household conditions make a difference


Just for interest, check this video around 1:46 - 1:48






The lady is purging the machine, you can clearly hear that there is condensation coming out of the steam wand followed by steam.


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## Obnic (Jan 14, 2014)

I purge to get rid of the water but also to optimize steam boiler pressure. I get the best microfoam with a pressure of between 1.2 and 1.4 bar. My boiler is set to 127c which yields a pressure of around 1.5bar. A quick snort empties the wand and brings the boiler down to my target pressure.


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