Agitation in French press extraction seems to be largely unexplored. We tried some serious agitation in the press this week, and enjoyed some very tasty results with our Koke. In addition to significantly increased extraction, the coffee tasted noticeably cleaner than even via the traditional Coffee Catcher method.
For the record, here's the process we used:
1. If you tend to use a finer French press grind, coarsen it up a few notches. On our Virtuosos, we found 27/26 led to over-extraction, and 31 was about right.
2. Use a half dose in an 8 or 12 cup press, in order to leave room for aggressive agitation.
3. Throw in a Coffee Catcher, pour and let brew stand for 3 minutes.
4. At 3:00, begin shaking the press vigorously in a consistent, circular motion. You should see a substantial whirlpool effect.
5. Shake continuously until about 3:45, and press at 4:00. Pour out right away.
So, would 4 minutes of continuous agitation inevitably over-extract? What about agitating during the first minute, instead of the final minute? There's room for more experiments here...
Wednesday, September 29, 2010
Monday, September 27, 2010
The Coffee Catcher Pull
I realized I hadn't yet written a single description of the Coffee Catcher Pull technique (a.k.a. the French Pull). This technique is referenced in a recent Seattle Weekly review, in an older Why Not? Coffee post, and in a previous post on this blog.
Here's how it works. You can see a video of the pull itself starting at 1:10.
1. Place the Coffee Catcher into your press, aligning the catches with the spout, and add coffee and hot water as normal. If you're using an 8 or 12 cup press, brew a half press of coffee. Otherwise, you will not be able to hook into the disc through the hot coffee!
2. Shake, submerge or stir in the coffee bloom according to your preferences.
3. After about 3 minutes and 30 seconds, gently insert the hook into both catches of the disc. This may take a few seconds. At about 4 minutes, pull the Coffee Catcher up through the brew and remove the cake.
4. Wipe the lips of the carafe with a tissue, and drop the plunger to trap any stray floaties.
5. Pour and enjoy!
Here's how it works. You can see a video of the pull itself starting at 1:10.
1. Place the Coffee Catcher into your press, aligning the catches with the spout, and add coffee and hot water as normal. If you're using an 8 or 12 cup press, brew a half press of coffee. Otherwise, you will not be able to hook into the disc through the hot coffee!
2. Shake, submerge or stir in the coffee bloom according to your preferences.
3. After about 3 minutes and 30 seconds, gently insert the hook into both catches of the disc. This may take a few seconds. At about 4 minutes, pull the Coffee Catcher up through the brew and remove the cake.
4. Wipe the lips of the carafe with a tissue, and drop the plunger to trap any stray floaties.
5. Pour and enjoy!
Coffee Catcher FAQ
1. Q: Where can I get a Coffee Catcher?
A: Right here. Unless you live in Seattle, we are not yet in a store near you. If you do live in Seattle, you can pick up a Coffee Catcher at Trabant or at Visions Espresso.
2. Q: What is the Coffee Catcher made of?
A: All parts are made of 100% stainless steel.
3. Q: What does the Coffee Catcher do?
A: Two things. First, the Coffee Catcher collects grounds for easy removal after brewing. Second, the Coffee Catcher seems to filter suspended fines out of the brew in such a way that the resulting coffee tastes cleaner and has a longer cup life. Yup, that claim sounds far-fetched. We didn't believe it either at first. Posts exploring the filtration effect here, here and here.
4. Q: How do you use the Coffee Catcher?
A: We originally designed the Coffee Catcher to be placed in the bottom of the press before adding coffee. After brewing and pressing, hook into the disc to remove the Coffee Catcher. Original video here.
That said, it turns out the Coffee Catcher offers intriguing possibilities for other brew methods. See experiments with coffee siphon pots, the Coffee Catcher pull technique (referenced in 5th paragraph here), and the Double Coffee Catcher technique (videos here and here), and a technique called multi-bed brewing (blog posts here and here). We expect to discover still other ways to use the Coffee Catcher in the near future. Stay tuned...
A: Daily, clean in three steps:
1. After removing the coffee puck, use the hook to scrape the puck into the trash, the compost, or over your plants.
2. Then give the disc a rinse under the faucet.
3. Next time you brew, insert the Coffee Catcher and add a little hot water to pre-warm your press. Shake the press gently to agitate any stray fines caught between the Coffee Catcher discs into the water. Dump the water into the sink and brew in your pre-warmed press.
Occasionally, do a thorough cleaning:
1. Gently unscrew and disassemble your Coffee Catcher using a flathead screwdriver. We recommend disassembling directly into a bowl.
2. Cover parts with hot water and a dash of Cafiza powder (eco-friendly phosphate free powder here)
3. Soak for 15 minutes, rinse in cold water and reassemble when dry. To condition the metal, you can soak the assembled Coffee Catcher in water for an hour afterwards.
6. Q: I see wrinkles around the edge of my Coffee Catcher mesh. Does it still work?
A: Yep! First, the steel discs themselves provide sufficient structure to lift and compress your coffee grounds into a cake. Second, our taste tests tell us that suspended fines trapped by the Coffee Catcher stay trapped regardless of wrinkle appearance or arrangement, perhaps because falling french press fines plug any gaps caused by wrinkles very early in the brew cycle.
7. Q: Why is the Coffee Catcher a disc instead of a cup shape?
A: Preferences for coffee amounts used in brewing vary, and doses may even change slightly depending on roast or type of bean. We designed the Coffee Catcher as a disc in order to trap any amount of coffee: half presses, full presses, even double-dose presses (see iced coffee post here). Also, a disc shape means the Coffee Catcher will not interfere with the French press plunger action.
8. Q: Does one of the Coffee Catcher sizes fit my press?
A: Probably, since we designed the Coffee Catcher to fit the most popular French press models. That said, let us know if you have a size that doesn't fit, as we're already working to add more sizes to the line-up.
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French Press Fines
This post is a loose follow-up to the cliffhanger at the end of my long and headache-inducing post on the chemistry of French press foam.
After concluding that French press foam might act as a sort of chemical scrubber for coffee fines (insolubles), I was eager to start comparing different methods for removing fines from the brew.
While I stand firmly with those who hold the palate as the final judge of coffee quality, the palate is inevitably subjective. I set out to measure suspended French press fines concentrations objectively -- and [SPOILER ALERT] probably failed to do so.
I prepared coffee in five different ways. First, I prepared coffee traditionally, brewing in a French press for 4 minutes and shaking in the coffee bloom at 3 minutes. After that, I tried the Wendelboe / Hoffman technique, the Coffee Catcher press technique, the Coffee Catcher pull (referenced here and here), and the double Coffee Catcher technique (videos here and here).
Referencing a video at The Other Black Stuff, I decided to pour the prepared coffee in each case through a clean paper filter and weigh the results using a gram scale.
After weighing the filters, I found the following (per approx. 900 ml of liquid coffee):
After concluding that French press foam might act as a sort of chemical scrubber for coffee fines (insolubles), I was eager to start comparing different methods for removing fines from the brew.
While I stand firmly with those who hold the palate as the final judge of coffee quality, the palate is inevitably subjective. I set out to measure suspended French press fines concentrations objectively -- and [SPOILER ALERT] probably failed to do so.
I prepared coffee in five different ways. First, I prepared coffee traditionally, brewing in a French press for 4 minutes and shaking in the coffee bloom at 3 minutes. After that, I tried the Wendelboe / Hoffman technique, the Coffee Catcher press technique, the Coffee Catcher pull (referenced here and here), and the double Coffee Catcher technique (videos here and here).
Referencing a video at The Other Black Stuff, I decided to pour the prepared coffee in each case through a clean paper filter and weigh the results using a gram scale.
 |
| The remaining residue looked pretty scary! |
Traditional - 3.1g
Wendelboe/Hoffman - 2.7g (-13%) (56 g solids removed)
Coffee Catcher Press - 3.0g (-3%)
Coffee Catcher Pull - 2.8g (-10%) (103 g solids removed)
Double Coffee Catcher - 2.3g (-26%) (134 g solids removed)
Did these numbers surprise me? Yes and no. Yes, in the sense that the results are not necessarily correlated to my palate's perceived cleanliness of flavor (which I assume is a direct correlation to suspended insolubles). My palate tells me all four variants are cleaner than the traditional press, but I would have rated the Coffee Catcher Press method as substantially cleaner than the number would indicate.
However, I wasn't surprised if the results reflect heavier, non-suspended particulates. This, I think is the "mud" that sinks quickly out of the brew, and I suspect it is not related as closely to perceived cleanliness. I noted that the three methods that involved the removal of large particulates easily beat the other two methods. Also, the only double-removal method tested removed far more weight than other methods. It's worth noting that the Coffee Catcher Pull measurement is skewed slightly by experimenter error: the disc slipped slightly part way up the carafe and leaked an unknown amount of solids back into the brew.
Is any of this significant? I'm still working on that one. I set up the test hoping to test differences within tolerances of a tenth of a gram. I was careful to test as large a volume of coffee as possible in order to exaggerate per ml differences. My statistics knowledge is rusty, but preliminary results indicate that these results are not necessarily significant (i.e. differences in weights could be chance alone). My instincts disagree with this assessment, and I'll post more as I discover more.
Finally, I'm circling back to square one. How do I measure suspended French press solids? This experiment shows that they appear to be too light and/or too small to be measured via paper filters. As an example, notice the tiny residuals that leaked through the paper filters on the drying plate. A smear like this leaked through the drying filters in each case. Perhaps these are the particulates I'm hunting for.
However, I wasn't surprised if the results reflect heavier, non-suspended particulates. This, I think is the "mud" that sinks quickly out of the brew, and I suspect it is not related as closely to perceived cleanliness. I noted that the three methods that involved the removal of large particulates easily beat the other two methods. Also, the only double-removal method tested removed far more weight than other methods. It's worth noting that the Coffee Catcher Pull measurement is skewed slightly by experimenter error: the disc slipped slightly part way up the carafe and leaked an unknown amount of solids back into the brew.
Is any of this significant? I'm still working on that one. I set up the test hoping to test differences within tolerances of a tenth of a gram. I was careful to test as large a volume of coffee as possible in order to exaggerate per ml differences. My statistics knowledge is rusty, but preliminary results indicate that these results are not necessarily significant (i.e. differences in weights could be chance alone). My instincts disagree with this assessment, and I'll post more as I discover more.
Finally, I'm circling back to square one. How do I measure suspended French press solids? This experiment shows that they appear to be too light and/or too small to be measured via paper filters. As an example, notice the tiny residuals that leaked through the paper filters on the drying plate. A smear like this leaked through the drying filters in each case. Perhaps these are the particulates I'm hunting for.
 |
| A dry smear of particles too small to be trapped by the filter. Are these the elusive suspended solids? |
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