High Extraction Brews vs Two Stage Immersion Filtration?

Coffee preparation techniques besides espresso like pourover.
dsc106

#1: Post by dsc106 »

I keep seeing Rao, Gagne, Decent, etc. pushing high extraction brews. The Tricolate brewer is the newest for this, and Gagne recently released a blog post on 10 minute Aerporess immersion brews.

Which got me thinking, specifically on the aeropress brew which is really just a long immersion brew + filtration (plus some mild pressure). Immersion is *much* better at evenly extracting coffee without channeling and all the other caveats of percolation (Hoffman has a video on that here: http://www.youtube.com/watch?v=09fNvoQMlGw). But immersion brew lacks, primarily, two things from percolation: (1) fresh water to carry away soluables, (2) filtration.

#2 is easy to solve - simply filter the immersion brew through a paper filter.

#1 can mostly be solved by simply immersing longer...? If not (I haven't yet finished "the physics of filter coffee" by Gagne, but I presume the fresh water may have something to do with it), couldn't one immerse grounds for say, X minutes (4? 5? 10?), then pour the immersion through a paper filter for clarity. Re-fill with remaining 50% water, brew another 2-8 minutes, filter again? This may be similar to 2 pour percolation brews, except we'd a have a perfectly even immersion extraction on pour 1, filter, immerse again for perfectly even extraction, filter. The times and amounts could be adjusted (i.e. it could be a 3-stage immersion brew... or stage one could be 2 minutes, and stage 2 could be longer at 8 minutes).

How would this not be superior to percolation brewing? It would maintain the benefits of both immersion (even extraction, no channeling) and percolation (refreshed, clean water + paper filtration).

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dsc106 (original poster)

#2: Post by dsc106 (original poster) »

Ok funny enough, I think exactly what I am talking about exists in the Hario Switch. It's basically a clever coffee that can be used identical to a v60 with a switch, hence the name:

http://www.youtube.com/watch?v=xKqWYmjXoag

But with this, as discussed, you can experiment - immersion, draw down, flip switch, immersion. Anyone tried it?

Also, why can't I find this guy on Amazon or a normal retailer? Just ebay? Too new?

baldheadracing
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#3: Post by baldheadracing »

I think the Switch sold out once James Hoffmann put out a video on it.

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yakster
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#4: Post by yakster »

dsc106 wrote: #2 is easy to solve - simply filter the immersion brew through a paper filter.
Not so easy, this almost always results in clogged filters and slow draw-downs, plus who really wants to use and clean both an immersion brewer and a filter?
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dsc106 (original poster)

#5: Post by dsc106 (original poster) » replying to yakster »

I don't think so... you can brew in a french press, then press, then pour through a separate filter. I'm not worried about the pragmatism of cleaning two devices, but about the science of the coffee extraction and resultant flavor.

Second, with the Hario Switch, for example, it would seem you can simply get rid of slow draw downs and clogged filters by grinding coarser and immersing longer. The draw down in this instance merely works to get fresh water. What I am inquiring about is changing the way we think of brewing altogether. With a forgiving and slower extracting (but quickly drawing down) coarse grind, we might work in several immersion pours and releases.

pham

#6: Post by pham »

Right now, I prefer the Aeropress over the v60 at the moment. It's a more even extraction and it tastes like it, too. The numbers can be misleading, as 22% might taste more like 24% on immersion if you steep it long enough. Texture on the Aeropress heavier, flavors lead into each other with more distinction (clarity by my definition), and it's much more friendly to small doses. The v60 is inherently just a little bit uneven, and sometimes that is desirable if you seek that for a certain coffee, say a nice natural. The v60 having "more clarity" i think is people conflating less texture as more flavor clarity.

jpender

#7: Post by jpender »

Immersion brews tend toward a limit, no matter how long you steep. Washing them a second time will extract more but is that really what you want?

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rmongiovi

#8: Post by rmongiovi »

You're at the mercy of diffusion. There's only so much solute that a given amount of solvent at a given temperature can hold. At some point the rate of diffusion from coffee to water equals the rate of diffusion from water back into coffee and then you're done. You might not achieve that balance if you drain the water before you reach it, but you can't go past it. You can indeed dissolve more by using fresh water but then you end up with a greater volume of water. If you had just started with that same greater volume for your immersion you would also have dissolved more of the coffee. In fact, you would have dissolved the maximum the water could hold (or run out of coffee to dissolve) if you gave it enough time.

I don't see how draining the water early can do anything but lower the extraction rate from the maximum possible.