Hi folks...
We live at elevation (6300 ft above sea level)...

Among other differences, this means water here boils at 202°F (94.4°C) instead of 212°F (100°C)

This surely must be affecting our shots we pull? It affects everything else, like our 3 minute eggs are really 6-7 minute eggs, and I wondered if any of you know how we should correct for this temperature/altitude difference?

I've known it accelerates our roasts some, but don't have a lock on how it affects our shot pulling and wondered if any of you have a lock on it? I know there must be some more precise info available...

My repair shop for the Expobar that sets it up is only at 4500 ft elevation, so their water boils at nearer 205-206°F...

Any info out there?

I'm sorry if you read this on another forum - I'm posting it a couple times in different locations to gather some direction and information...thanks for your patience...

I think it can be an advantage because the water will only go so hot. I think coffee stays fresher a bit longer for some reason maybe less oxygen? Who knows. I have been thinking that brew pressure should be adjusted according to altitude. Some how related to the difference in pressure inside the basket and out side the basket. Sea level is 1 bar a 9 bar brew pressure is a 8 bar difference. So if i want to maintain a 8 bar difference at an altitude that has air pressure less than 1 bar I should brew slightly lower pressure. I have only speculated this theory based on thinking about it. And one day I am going to pull some shots at home at 4500 feet. Pack up the machine coffee and grinder, drive to snowbird and make a a shot at 8500 feet, then get on the tram and make a shot at the ski patrol hut on hidden peak at 11000 feet. I think about it and wonder what will happen. I begin to think that a varied brew pressure would be something I would adjust in this scenario.

Thinking about coffee is fun.

Jon

Hi Larry,

I am up in the air with you (6700 feet at the house), and I previously lived at sea level (although I did not know how to do the 'water dance' then). Water boils at 199 F at my house. You just need to get to know your machine and the coffee. For my setup, I run water through the group around 8 sec prior to locking in the pf, which is just past visibly boiling (and well past flash boiling) to pull shots around 200 F, which I prefer for the blend I normally use). The water dance is described here http://www.home-barista.com/hx-love.html.

I don't have a Scace device nor a temp probe, but I used a cut-down styrofoam cup with a milk thermometer stuck through the side of the cup to learn more about the temp at the group based on flush time. It was not necessarily accurate, but it is consistent (assuming you run the same amount of water, etc), so you can learn how much the temp goes up or down with longer or shorter flush times, then adjust for taste. So, flush for 7 sec., then put the cup over the group and run the water for 10 s and check the temp. Wait for everything to heat back up, flush for 8 sec then repeat. Run several times, going longer and shorter on the flush to help eliminate residual heat effects, etc.

If you don't have one, get a timer. It pays to be extremely consistent with time, since that is the only variable you can use to control the temp every shot. Also, be sure your boiler is not set too high 1.1 - 1.2 bar should probably be the max.

Hope this helps.

Enjoy your experience, James

malachi wrote:David Schomer's Espresso Coffee: The Denver Effect

With all due respect to David Schomer, he's also the same guy who said conical grinders "shave" the coffee into ribbons, which we know from Scanning Electron Microscope analysis of ground coffee isn't true. Specifically in his article Chris cited:

I played with temperature and pressure all weekend and the best I could do was to brew at about 200 degrees, dancing around sourness to get the crema to feature less gas.

Assuming his espresso machine is PID controlled, how could temperature come into play during the brewing process? It's a pressurized closed system. He continues:

As the espresso came into contact with the air it outgassed oxygen violently. The effect on the espresso crema was like a hurricane hitting a wet tissue on a clothesline. It literally shredded the crema before your eyes. And as you know the crema is responsible for holding the aromatic flavors in place long enough to savor them. It is structural to an espresso coffee, not merely for mouth feel although that is pleasing. In addition the crema features a very low surface tension allowing espresso coffee flavors to penetrate in between the taste buds on your tongue, providing espresso's unique long lasting after taste.

Larry, does this description match your experience? The comment about outgassing oxygen is especially puzzlingly; wouldn't it be carbon dioxide? If so, I would try lower crema production coffees. Or grinding the coffee and then letting it degas for a few minutes, a trick that helps overly-fresh coffee closer to sea level.

PS: For those who also follow CoffeeGeek, see Larry's cross-post of the same question.

Hey everybody thanks for all the responses so far...

I appreciate the Schomer article, and yes Dan, that is somewhat what's happening.

With my naked portafilter I go from dark chocolate drips (when I'm dialing in the grind) to expanded tornadic action with elongated ''tornadoes'' in the middle of the portafilter that extend down about 1.5 inches or longer into my shot glass...

It sure is not as neat-n-tidy as the videos I see on YouTube (and elsewhere). The taste is fine, and I'm inclined to not worry near as much about surfing the temp or the head being much too hot. I am planning to refine my roasting (new roaster ordered), because the beans I have now were roasted in about a 13 minute total roast cycle which is a bit fast for deep/rich espresso.

The effervescence described in the attached pdf is pretty accurate, and I don't know if it's oxygen, carbon dioxide or just air, but it's definitely ''there...''

Anyone else who has insight or just some informed guesses please chip in! I've lived here for 34 years and we will be here at least 4 more years. The machine was setup by a firm which sets all the local shops, and he mentioned tweaking the pressure for ''here'' so I'm inclined to think that it's pretty close to where it needs to be (just set/calibrated about 3 weeks back).

Thank you everybody...

I did experience a loss of crema using a fresh bag of Black Cat when I first started really paying attention and buying fresh coffee (about 1 1/2 years ago). Same thing, coffee had almost no crema once the shot finished. As the coffee aged, the crema came back, I just chalked it up to not waiting long enough before trying to use the coffee (I think 10 days post roast was where it really started to settle in). I have not considered it since then, nor had I considered that at high elevation you may have to age the coffee a bit more, though I always wait 5 -7 days minimum before using fresh coffee.

My shots generally turn out pretty well, with good visuals, plenty of crema and good flavor. I buy coffee from Jon's (Regulator Johnson, Caffe'd Bolla) often, and although my shots pulled with his coffee are not the same as in his shop, they are still very good (sometimes excellent - but that is up to me) .

ljguitar wrote:I appreciate the Schomer article, and yes Dan, that is somewhat what's happening.

Thanks for the confirmation of David's observations. FYI, there are a few other threads on this subject that you may find helpful:

• How does high altitude affect brewing?
• The Denver Effect?
• Water boils at 195F
• High Altitude Brewing

I had forgotten these were linked from the site's FAQs and Favorites.

Hi Dan...
Thanks for the links, and they are interesting. As there was quite a bit of not-quite-agreement here I need to wade back and see what the practical solutions are.

What Jim Schulman described about the beginning of the shot being good but the end of the shot killing the crema (don't remember all the technical reasons why) in one of his explanations...that is a good summation of what's happening with my shots.

Also,

I ran a coffee bar at elevation a number of years ago.

It's a PITA. And if you also have low humidity and/or big swings in temp day to night it becomes even more of a challenge.

The things that we noticed:
1 - you cannot rely upon "parameters" for brewing that are provided by people at or near sea level. You have to experiment and determine your own models.
2 - coffees that are optimal at higher brew temps seemed difficult if not impossible to get good shots from.
3 - naked portafilters often confused the issue - making you think that you had poor mechanics when in fact it was the weird "off gassing" effect noted in the Schomer article
4 - the window for good coffee (days from roast) was incredibly narrow. Coffees that were a day too young were nearly impossible to work with and coffees a day too old were stale and flat.
5 - double boiler machines were nearly required if you wanted any flexibility and consistency.
6 - pump pressure seemed best for us at right under 9 BAR (but probably is dependent on your own elevation)
7 - updosing was very problematic and in fact for many coffees a downdosed triple basket was a great solution.