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Permalink Reply by Jason Haeger on September 17, 2008 at 12:30pm

I like Brady. He's like my bX twin. I always check to see if he's already said what I plan to say before posting a reply in a thread.

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Permalink Reply by Chris DeMarse on September 17, 2008 at 12:53pm

jason,
I would both agree with you in your emphasis on not only rate but material. However, the rate of interaction determines the extraction. Our creating resistance of flow is to give a specific amount of time for particle interaction. In essence, our 3-4 minutes with a certain grind particle size is what is to be found relatively optimal for brewing for time of interaction between water particles at a certain energy (195-205 F), meaning that our resistance in terms of water flow gives us a set contact time between the water and the coffee. If we decrease our temperature in that same time period, the lack of heat energy reduces the frequency of interaction between water and coffee particles. But all of this is based on an assumption of atmospheric pressure being at a certain rate of resistance to heat transference and particle interaction. You are right, in that all coffees have a different "ideal" temp. within the set range over a certain amount of time, but there has to be an account for the resistance of energy transference directly related to the brew temperature in reduced atmospheric pressures.
Unfortunatley, there's not much to compare it to relatively. We all know that when we brew outside the parameters of ideal brewing we have to take into account a different reaction on the coffees part. A toddy or cold brewed coffee brewed over 36 hours is not going to taste the same as the same coffee brewed at 201 in four minutes in french press because the factor untalked about to this point is not the issue of what is being extracted, but how temperature is changing it; namely the coffee oils. Obviously you are not getting the "same" extraction out of the same coffee in CO with a certain temperature because by virtue of changing temp. you are also changing the oil composition...
sorry... i'm just processing this out on paper... it's how i make sense of things sometimes

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Permalink Reply by Chris DeMarse on September 17, 2008 at 12:57pm

I do see where your idea of increasing pressure to achieve temperature might be your answer, if coffee does not extract appropriately at lower temperature like I have so grandiosely supposed.

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Permalink Reply by Jason Haeger on September 17, 2008 at 1:10pm

I'm not saying your theory is right or wrong. I'm just saying that my own experiences at high altitude disagree with it.

In theory, it looks good. Then I tried it. It doesn't work. (at least, it didn't for me)

Atmospheric pressure isn't going to play THAT big of a role, and if anything, reduced atmospheric pressure (as is the case in a higher altitude) would reduce the rate of extraction, or brewing under pressure would increase the required dwell time for adequate-proper extraction. This would leave espresso as pretty well useless, and the aeropress as virtually unable to produce a "coffee concentrate" in the time it takes.

Increased pressure increases the extraction rate, thus reducing the required dwell time. This was mentioned much earlier in the pressure-cooker analogy.

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Permalink Reply by Brady on September 17, 2008 at 1:28pm

Thanks guys :)

This does help explain why the perc'd coffee I had last time we were in the rockies was not nearly as bad as I expected...

But really, nobody here from Denver? Boulder?

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Permalink Reply by Chris DeMarse on September 17, 2008 at 1:29pm

sorry if I sound like I'm disagreeing... I'm just processing and you clearly have way more experience than I do... I think I'm learning the more I read your posts... I would say that pressure, though, is not necessarily what creates increased extraction... it is rather resistance to pressure. I hate to go there with espresso because this post had to do with drip/press coffee, but you can have 9 bar pulling through coffee that is coarsely ground and have underextraction, but the right particle size relative to the freshness of the coffee is what creates adequate resistance resulting in an appropriate exctraction.. of course all this assumes the appropriate dose weight is used... but I could see where true pressure is only achieved through resistance, thus your statement.

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Permalink Reply by Nick Griffith on September 17, 2008 at 7:39pm

All this sounds interesting, but really, no one here from Denver? damn.

I'm an hour or so away from Lake Arrowhead, so I'll plan a trip in the coming weeks and let you know what I find.

I am a little surprised no one has brought up the idea of using softer water to extract more out of the coffee. If under extraction is the problem at altitude, then I'm curious what a difference the water would make. I'll have to bring a couple of different bottles of water with me when I go to the hills!

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Permalink Reply by Jason Haeger on September 17, 2008 at 8:16pm

Softer water will extract more things, but not necessarily the right things. Hitting the right temperature for the coffee seems to be fairly critical, but you can make toddy up there and add the concentrate to hot water if you want to be safe.

It's a very different cup than energy extraction, but some people quite like it.

If I were in your shoes, I'd be packing an aeropress so I can add my own atmospheric pressure to the party.

Oh, and have you tried asking people in Denver rather than hoping they'll find this thread?

http://www.baristaexchange.com/main/search/search?q=Denver

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Permalink Reply by Nick Griffith on September 17, 2008 at 8:31pm

So, you've tried the softer water?

Thanks, but I'll take a Red Bull over an aeropress - but thats another forum discussion.

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Permalink Reply by Jason Haeger on September 17, 2008 at 8:36pm

Yeah. This is pretty established stuff.

I understand the profile of the Aeropress isn't for everyone, and I'm still waiting for the promised metal filters to hit the market (it's been how long now? Terry Z.. you listening? Mark P. ? Anyone else who said they'd bring them to market? ).

You could always try cowboy coffee..

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