espresso elevation

elusive espresso... theorize, philosophize!

espresso elevation

Postby Emily Oak on Tue Mar 30, 2010 2:03 am

I was talking with a customer and colleagues over the weekend about espresso behaviour at different elevations.

Our customer owns and operates an espresso bar at approx. 1000m above sea level. (3280 feet).

He was discussing how the elevation effected espresso extraction and therefore his coffee ordering and resting patterns - especially as he was using naked PF's to extract all his shots.
At elevation he was saying the coffee was more gassy than even the freshest coffee he'd experienced at lower elevations.

He also discussed having problems getting steaming correct in terms of boiler temperature and wet/dry steam balance.

Not being a scientist in any way, I was wondering if it's probably due to less oxygen at that altitude and also the boiling point of water being different.. (clutching at straws here of basic high school science.)

Second part of the question - with the 2011 WBC being held in Bogota, Colombia at approx. 2600m above sea level - how do you think this might impact on competitors in terms of preparation of their coffee and choices? (If at all?)

Any ideas, thoughts or solutions/explanations?
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Re: espresso elevation

Postby IanClark on Tue Mar 30, 2010 4:38 am

Interesting questions!

Regarding the gassy crema, it may be something to do with the increased pressure differential between inside the basket and outside? My guess is that this would effect crema formation as CO2 precipitates out more quickly and forms more or larger bubbles?
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Re: espresso elevation

Postby JakeLiefer on Tue Mar 30, 2010 4:40 am

Interesting thoughts, I never thought about this and don't have any experience, so I'll leave the taste evaluations to those living on the side of a mountain. I hope Novo Coffee can post some information from their experience, as they roast and brew in Denver, Colorado at an elevation of 1600m (5,280ft). In Denver, water boils at 202F (95C), pressing up against the espresso brew temp. In Bogata, the issues increase. There, water boils at 196F (91C). Given that water boils at that temp, I think the boiler would be a few degrees even lower than that. And ironically, unless WBC rules are changed, every competitor will receive a 0 on their espresso due to failing to comply with rule 2.2.1.C: 'Espresso shall be brewed at a temperature between 195-205 degrees Fahrenheit.'

Perhaps we'll see a very different take on espresso and a break from the standard definitions. I remember talking to someone at last years MARBC/NERBC competition (Jordan Barber?) who worked for a chef in NYC that turned down the boiler temp to something like 160F, pulled 45 second shots and was still getting good shots. While the machines won't be at 160F in Bogata, there will definitely be a difference in shot temp, time and evaluation that need to be adjusted for.
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Re: espresso elevation

Postby James Hoffmann on Tue Mar 30, 2010 5:10 am

Water boils at low temperatures under those specific atmospheric conditions - the inside of a bakset is not under normal atmospheric pressure so the water won't be boiling. The inside of a steam boiler is also under its own pressure so should steam the same as anywhere else.

Coffee brewed at whatever altitude should taste the same under espresso pressures. Shouldn't it? I can see presspots acting differently - though I always thought the problem with boiling water was that it had enough heat to extract unpleasant tastes. If the water is 202F and boiling surely it doesn't have the abnormal capacity for extraction/the coffee doesn't extract more easily under these circumstance?

The pressure difference is interesting though - though for relatively small change I am surprised to see such a big influence. As hot water is less capable of holding onto dissolved CO2, unless becoming supersaturated under pressure, I guess that the problem is indeed that CO2 is coming out solution faster than usual creating bigger, less stable bubbles.
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Re: espresso elevation

Postby Mike Strumpf on Tue Mar 30, 2010 6:20 am

I don't have any explanations for why things happen at altitude, but being at over 5,000 ft I have some experience with higher altitude espresso. A few other people on the board can chime in as well since they have seen what happens at the Mountain Regional Barista Competitions.

We end up resting coffee for a silly amount of time, and then have a shorter window of acceptable shots than at sea level. I don't usually produce crema without very big bubbles and premature blonding until about 19 days off roast in an unsealed bag (using a Robur and a GB/5, I have found that this changes depending on the grinder used and how much pre-infusion a machine gives). You can still produce extraordinary shots, but you have to change your approach to resting.

Milk steaming can also be done to the same quality as at sea level, but your stretching period needs to be very short compared to sea level.

For the 2011 WBC I don't think competitors will need to choose a different coffee or milk, just be prepared to change their resting and steaming. I would advise against doing an on stage coffee brewing (in addition to their espresso) as it is harder to make amazing coffee when you are starting out at a low boiling temperature.
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Re: espresso elevation

Postby IanClark on Wed Mar 31, 2010 4:49 am

James Hoffmann wrote:

Coffee brewed at whatever altitude should taste the same under espresso pressures. Shouldn't it?


I'd imagine so. Is the water not under at least ~3 bar or so under line pressure alone, with a boiling point of closer to 275F? Unless I'm missing something there shouldn't be any change to the extraction, although I guess there will likely be a change in crema formation.
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Re: espresso elevation

Postby nick on Wed Mar 31, 2010 9:38 am

Old article from David Schomer: Espresso Coffee: The Denver Effect (PDF)
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Re: espresso elevation

Postby John P on Wed Mar 31, 2010 5:47 pm

Boiling point here in Salt Lake City is approx 204.1 F. Even with the Synesso, it's impossible to pull a good shot if I go much above 203 F.

Our espresso is roasted to work best from 198-200 because of this.
I adjust our roasting profiles approx -13 degrees F per "standard" roasting curves to account for the altitude. Most of our beans for espresso are dropped at 427-431 F @12:30 to 14:30 depending on batch size.
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Re: espresso elevation

Postby j.k.bladyka on Fri Apr 02, 2010 6:37 pm

This is my first post here on Coffeed, so first I'd like to thank everyone who I've been reading for a couple years. Currently I'm a barista/roaster at Coal Creek Coffee Company in Laramie, WY, elev. 7200ft asl.

I've been struggling with this question for two years now, not so much the what, but the how and the why. Water boils at 199 degrees F here, and there is nearly 20 percent less oxygen in the atmosphere.

I believe that there is a difference in extraction. Temps must come down, otherwise the water is boiling, and no matter what the temperature, it's the physical attributes of boiling water that mess with extraction, right? That inherently changes every other variable, right? Has anyone tried making espresso in a setting with greater than one atmosphere of pressure? Submarine Spro?

I'll be paying close attention to the differences when I come down to Anaheim and am looking forward to keeping a close record. At the USBC last year, I only remember that my espresso was a dream, crema retention seemed to last forever, the margin of error for exceptional shots seemed to increase, and it was much easier to dial in.

The owners of Coal Creek have been at this awhile (since 1995), and I would strongly disagree with Schomer's statement that it can't be done, based on a weekend in Denver. I agree with Mike about resting and about milk. Our espresso rests for at least two full weeks in unsealed tubs before we can consider using it, it's usually around the end of the third week that we find the best shots. This however, I think is a question concerning what happens during roasting at elevation as much or more than it is about espresso.

I'm very interested in learning more about this, and I invite anyone passing through to come play coffee at altitude with me.
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Re: espresso elevation

Postby Brent on Wed Jun 23, 2010 4:33 pm

from memory the change in boiling point is to do with the air pressure at altitude, and this in turn affects the other variables in greater or lesser ways...
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Re: espresso elevation

Postby Emily Oak on Tue Aug 17, 2010 2:04 am

I came across this article today. Not so much to do with espresso, but just altitude/boiling.

http://www.seriouseats.com/2010/08/how- ... rious+Eats)
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