malachi wrote:So, as noted above... avoid high temp espressos.
In terms of what "high temp" means in this case, you'll need to look at what the boiling point is at your elevation. Odds are that worst case is you're only ruling out the rare outliers like the Vivace and Victrola espressos that prefer temps over 203f.

Chris,

If you made an espresso using Vivace beans (or others where supposed optimal brew temps are in the 203-204F range), what would be the temperature of the beverage as it exits the PF? At 6000 feet, the boiling point is around 201F, and I doubt that even an espresso extracted at 204F would exit the PF at a temperature greater than 201F.

Leadville, CO, at ~10,100 feet has a local boiling point of around 193.5F, which probably would be limiting. I'd suggest drinking green tea in that situation

ken

I would think that humidity and temperature swings would be your biggest battle. Lived in Denver and spent a lot of time in the high country (above 10,000 feet camping/hunting). Things get strange up there. You also lose 1/3 of the horsepower per 1000 feet increase in an internal combustion engine at around 6K if I remember correctly.

The humidity swings would cause a lot of grinder adjustment changes. Being low oxygen, I would expect things like crema to be short lived. Not much you could do about that, just drink faster. Crema is not the end all and be all of espresso. I have had very good shots with very little crema and horrid shots that were all crema. Concentrate on grind adjustments and flavor and less on how pretty the shot looks in the cup and you will probably be just fine. If it tastes good, stop chasing the white rabbit and enjoy the coffee.

Ken Fox wrote:...At 6000 feet, the boiling point is around 201F, and I doubt that even an espresso extracted at 204F would exit the PF at a temperature greater than 201F.

Hi Ken
A common misperception is that boiling point is fixed - in fact today at our house with the barometer where it's at, water is boiling at 199°F (92.8°C)

The effect on my shots (while using my naked portafilter) is that a tornado forms, rich, thick & dark. Then about 2/3 of the way through the pull, it rapidly turns into a big fat bubble, distends and expands the ''tornado'' and bursts while still tiger striping. The crema tops 2.5 oz mark in my shot glass, then within seconds is collapsed to being 3-4mm thick.

I have been pulling a blank shot to cool the group while grinding/tamping, and the quality of the espresso itself is improved...but the crema is wonky.

The amount and condition of crema we get (breaks down quickly) has been this way for years, but I've been removing the crema from our shots anyway, and they are really wonderful tasting. The pucks are solid and not breaching, so I concluded that it's the water at the end of the shot heating back up and vaporizing.

What say ye?...

cannonfodder wrote:...Crema is not the end all and be all of espresso. I have had very good shots with very little crema and horrid shots that were all crema. Concentrate on grind adjustments and flavor and less on how pretty the shot looks in the cup and you will probably be just fine. If it tastes good, stop chasing the white rabbit and enjoy the coffee.

Thanks Dave - I appreciate the advice. I'm working on re-establishing & improving my ritual. I'm actually reinventing it a bit so my wife can learn to pull decent shots. I've been slightly overdosing, and using a leveling tamp with very little pressure & we are getting dynamite shots...

But as I have mentioned in other posts, the crema is wonky.

ljguitar wrote:Hi Ken
A common misperception is that boiling point is fixed - in fact today at our house with the barometer where it's at, water is boiling at 199°F (92.8°C)

The effect on my shots (while using my naked portafilter) is that a tornado forms, rich, thick & dark. Then about 2/3 of the way through the pull, it rapidly turns into a big fat bubble, distends and expands the ''tornado'' and bursts while still tiger striping. The crema tops 2.5 oz mark in my shot glass, then within seconds is collapsed to being 3-4mm thick.

I have been pulling a blank shot to cool the group while grinding/tamping, and the quality of the espresso itself is improved...but the crema is wonky.

The amount and condition of crema we get (breaks down quickly) has been this way for years, but I've been removing the crema from our shots anyway, and they are really wonderful tasting. The pucks are solid and not breaching, so I concluded that it's the water at the end of the shot heating back up and vaporizing.

What say ye?...

The altitude of Cheyenne is 6155 feet, according to Dr. Google. In order to have a local boiling point of 199F, you would have to be experiencing barometric pressure of 29.15 mm of mercury, which would cause your boiling point to go down to what one would experience at 7000 feet under "more normal" circumstances.

I have just gone to the National Weather Service website for the weather observations for Cheyenne, WY, two minutes ago. THEY state that the barometric pressure in Cheyenne is 29.80 mm of mercury right now, and they give the altitude of Cheyenne as 6158 feet.

Using this online calculator, http://www.csgnetwork.com/h2oboilcalc.html , the calculated result for your local boiling point is 200.403 F at this point in time. I don't know how you have calculated a local boiling point point of 199F, and if you have observed this on some sort of temperature measuring device, I would question the accuracy of said device.

Using the same calculator and my local figures, the calculated boiling point for my town (elevation 5850 feet; current atmospheric pressure of 30.10mm of mercury), at this instant is calculated at 201.625 F, or roughly one degree higher. I am not having any of the aberrations in my espresso production that you report above.

You can draw whatever conclusions you like from this, however unless you live at a substantially greater elevation than the altitude I cited above (6155 feet), or if your barometric pressure is substantially different from what the National Weather Service reports, I have no explanation for your observations.

ken

Hey Ken
As a matter of record, my house elevation is over 6480 ft above sea level checked with an altimeter (a friend is a pilot) and there are places in the city which are above 6700 ft. - we have hills here.

I just take my barometric reading from weather dot com, but I don't usually check it before pulling shots.

My point is not to see how perfectly we can calculate the boiling point. I'm just collecting ideas while I'm working on understanding and shaping (when possible) the variables I need to work through to pull great shots at this elevation.

Thanks for the interaction...

ok i am wrong.. i guess ambient air pressure does not change with altitude? i understand that its a closed system. until the espresso leaves the basket and is in a environment at ambient air pressure.

what i dont understand is how come when i make espresso using the mini i get killer smooth crema then i turn around and use the kony a minute later with the same roast of coffee same dose 19g same basket, PF, extraction volume and time, same tamper , the shots from the kony collapse and fizz out.

to me it looks like what happens on mr wizard when he puts a cup of soda water in the vacuum and all the gas explodes out of it.

hrrrm.

jon

ljguitar wrote:Hey Ken
As a matter of record, my house elevation is over 6480 ft above sea level checked with an altimeter (a friend is a pilot) and there are places in the city which are above 6700 ft. - we have hills here.

I just take my barometric reading from weather dot com, but I don't usually check it before pulling shots.

My point is not to see how perfectly we can calculate the boiling point. I'm just collecting ideas while I'm working on understanding and shaping (when possible) the variables I need to work through to pull great shots at this elevation.

Thanks for the interaction...

Larry,

Mountain towns in the western US have houses at various elevations, which is why I qualified my answer. Altimeters, of course, need to be calibrated in order to give accurate results, and they are normally calibrated with the atmospheric pressure. Of course, that creates a bit of a chicken and egg phenomenon, unless you have a barometer at home that has been calibrated and (maybe) is traceable through NIST

Crema collapses at different rates depending upon a whole host of factors of which altitude is probably a very minor player except for a very small number of people who might read this thread. These factors include the coffee you are using (type, age after roasting, storage after roasting, grind quality and setting,) espresso basket preparation, and water composition, to name just a few.

ken

True ambient air pressure does change with altitude:

The values reported by your local weatherman and/or the National Weather Service are referenced to air pressure at sea level on a standard day - 29.921 "Hg. From the standpoint of espresso machine boiler temperature (typical Hx, non-PID machine), the mean boiler water temperature is governed by the thermodynamic properties of steam/water and all things delicious in between. These properties are based on the absolute pressure within the boiler wherein absolute pressure = gage pressure + true barometric pressure.

Page 2 of the first link which Dan provided has a graph which shows average temperatures as a function of average boiler pressure for various altitudes.

Ken Fox wrote:Leadville, CO, at ~10,100 feet has a local boiling point of around 193.5F, which probably would be limiting. I'd suggest drinking green tea in that situation

Bite your tongue! Tea is for evenings, and where the coffee is absolutely intolerable.
I do remember some advice about high altitudes in this thread a few years ago, and some good advice from the guy that you'd probably call if your espresso machine weren't doing as it was told in Leadville.