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Date: 09 May 2007 12:02:15
From:
Subject: How does altitude affect pulling shots?
I travel quite a bit around the US in my RV. As such, I carry an
espresso machine (KitchenAid Proline) with me and have often wondered,
will elevation affect my shot pulls? To me it would seem that, since
the boiling point of water decreases in relation to increasing
elevation it would mean that I need to adjust my boiler temp
accordingly. Is this correct? From personal experience I've had to
adjust the grind to keep shot consistency since I don't have a PID as
yet. Should I really be worrying about adjusting the pump pressure
instead?
Thanks for you help,
Nathan





 
Date: 09 May 2007 18:09:22
From: Steve Ackman
Subject: Re: How does altitude affect pulling shots?
In <1178737334.962073.127900@w5g2000hsg.googlegroups.com >, on 9 May
2007 12:02:15 -0700, bestmochalatte@gmail.com wrote:
> I travel quite a bit around the US in my RV. As such, I carry an
> espresso machine (KitchenAid Proline) with me and have often wondered,
> will elevation affect my shot pulls?

Not really. At really high altitude (say over
7000' just as a wild guess), you might get larger
bubbles in your crema, and you might get a bit of
flash to steam initially. See
http://twoloonscoffee.com/map/boiling_point.php
for altitude/temperatures where that might happen.
If you do get a flash of steam, that'll immediately
cool the group, so the rest of the shot should proceed
fairly normally. The highest we lived was 6181' and I
can say from experience that there's no real difference
pulling a shot between there and sea level that a bit of
grinder adjustment won't solve.

> To me it would seem that, since
> the boiling point of water decreases in relation to increasing
> elevation it would mean that I need to adjust my boiler temp
> accordingly. Is this correct?

The key variable isn't the water temperature in the
boiler, but the temperature at which your espresso
exits the basket. Since you're also now dealing with
a solution of sugars, acids which who knows all what,
the boiling point of espresso is higher than water, so
you have one more variable working in your favor for
your espresso behaving normally.

> From personal experience I've had to
> adjust the grind to keep shot consistency since I don't have a PID as
> yet.

It doesn't matter whether you have a PID or not or
whether you're travelling or not. You have to adjust
your grinder because the coffee ages, humidity changes,
etc.

> Should I really be worrying about adjusting the pump pressure
> instead?

Pressure is a function of the difference behind the
sensor (whatever that might be) and the ambient
pressure, so if you have a pressure gauge in the puck
that reads 132 PSI at sea level, it'll still read 132
PSI at 9000'.

If you want to adjust your pressure to find the sweet
spot for your favorite blend, by all means, go for it,
but when you're travelling, I wouldn't give it a second
thought.


 
Date: 09 May 2007 17:54:36
From: Eric Svendson
Subject: Re: How does altitude affect pulling shots?
See the chart, about 7 posts from the end here:

http://www.home-barista.com/forums/how-does-high-altitude-affect-brewing-t1494-20.html#30820

Eric S.

<bestmochalatte@gmail.com > wrote in message
news:1178737334.962073.127900@w5g2000hsg.googlegroups.com...
>I travel quite a bit around the US in my RV. As such, I carry an
> espresso machine (KitchenAid Proline) with me and have often wondered,
> will elevation affect my shot pulls? To me it would seem that, since
> the boiling point of water decreases in relation to increasing
> elevation it would mean that I need to adjust my boiler temp
> accordingly. Is this correct? From personal experience I've had to
> adjust the grind to keep shot consistency since I don't have a PID as
> yet. Should I really be worrying about adjusting the pump pressure
> instead?
> Thanks for you help,
> Nathan
>




 
Date: 09 May 2007 12:53:40
From: Karl
Subject: Re: How does altitude affect pulling shots?
On May 9, 3:02 pm, bestmochala...@gmail.com wrote:
>To me it would seem that, since
> the boiling point of water decreases in relation to increasing
> elevation it would mean that I need to adjust my boiler temp
> accordingly.

I'm no engineer, but assuming your machine has a boiler, not a thermal
block, the boiler is sealed and any pressure change outside of it you
encounter at higher elevations should not have any affect. (Water does
not boil at a lower temperature at higher elevations if it is inside a
sealed boiler.) The pressure as you pull a shot should, similarly, not
be affected; the pressure stat should maintain the pressure. Only when
the coffee exits the puck would it be affected by the outside
pressure. If it were hot enough, perhaps it would boil off at higher
elevations, but I doubt you'll be at elevations where this could
occur. The coffee exiting the puck is going to be below the boiling
point of any place you are likely to be, I would think. There might be
some changes in the crema, but you should be fine. There is at least
one regular altie who lives in Denver or somewhere like that. I
believe he reports that elevation has little effect and he is able to
pull excellent shots.

Karl "but I live at sea level, just to be safe" Rice