uRabbit Senior Member Joined: 15 Jan 2013 Posts: 50 Location: Seattle, WA Expertise: I live coffee
Espresso: AeroPress Grinder: Bodum Bistro, Hario Mini Drip: Chemex Roaster: DOMA
Posted Thu Mar 7, 2013, 8:17am Subject: What's going on here? Can't refine Chemex?
Chemex 6-cup Bodum Bistro Burr Grinder Bonavita gooseneck Square natural filters Filtered water Coffee roasted within 15 days at MAX Dose - 21g : 350mL Yield - ~266mL
I am having trouble getting this Chemex dialed-in, still, after almost 40 brews. I keep a coffee log, so I know what to change or keep. Trouble is, I'm just not sure that's doing it...
This morning, it is underextracted. Other mornings, it'll be bitter. Yesterday, it was almost perfect; first brew from new roast, roasted on the 4th.
Some people said our bloom wasn't being given enough time, so I have stepped it up from 45s to almost a minute. The same people also said our grind was too fine so I stepped that up from an 8/12 to a 9.5/12. So, obviously, the brews are quicker, but I'm not sure that it has really changed the brews at all. Yesterday, we ground at this new setting as well, and it was a great cup.
My pour times are generally the same. Yesterday I did a 56s pour, but this morning it was 1m 5s (yet this morning it was underextracted). Not really sure what is going on here. :(
edit: Opinions were based off of the video posted here.
Posted Thu Mar 7, 2013, 12:13pm Subject: Re: What's going on here? Can't refine Chemex?
With pourovers, there's interaction with the percolation rate, contact time, and grind size.
When the delivery rate (the rate at water introduction) overruns the percolation rate, then the brew will trend toward an immersion brew. Immersion brews yield a lower strength for a given brew ratio. When you're in the "soaking" pourover range, you're somewhere in-between an immersion brew and a percolation brew - and your extraction will be some estimate between the two methods of calculating it.
Remember, extraction is simply an attempt to have an objective proxy for taste - trust your taste first. If you're getting technical underextraction (i.e. lower measured TDS than you expect from the calculation) but it tastes good, and your grind and contact time are normal, you're probably hitting extraction well - you're just not using the correct method to calculate it.
The perfect pourover is when the delivery rate is just at the percolation rate, so that the dissolved coffee solution is drained out as new brew water is introduced. Total delivery time I've found should be really decent at around 3:30, and the last of the drops come out around 4ish minutes. Then for me the trick is finding the ground setting to achieve my desired percolation rate.
Or, you can do the dump and drain like starbucks. That's basically a CCD with no steep time. And THAT will underextract.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Thu Mar 7, 2013, 1:15pm Subject: Re: What's going on here? Can't refine Chemex?
I use nearly the same set-up - a Chemex 8-cup with oxygenated filters, a Bodum Bistro Burr grinder and the Bona-vita variable temperature electric kettle.
I would suggest the following:
Grind finer. I have had better luck using the pour-over icon on the Bodum when doing a single mug; it sounds like you may be two settings coarser? If I am doing enough for two mugs, I will set it at the pour-over icon plus 1.
Less blooming. I understand that once your coffee starts deflating you can start pouring. Is your coffee blooming for 45s-60s? I am usually <30s.
Pour slowly with pauses. I have seen videos on H-B and at Intelligentsia that seem to imply you can just "dump and drain" with the thicker Chemex filter. That hasn't been my experience. I need to be slow and deliberate and take brief pauses every 100g of water or so, and not letting the water get much higher than the initial level of the grounds.
Drink more. We typically consume our coffee 3-10 days after it was roasted. After that I can taste a difference - not necessarily bitter but the flavors are off. 15 days may be aggressive.
uRabbit Senior Member Joined: 15 Jan 2013 Posts: 50 Location: Seattle, WA Expertise: I live coffee
Espresso: AeroPress Grinder: Bodum Bistro, Hario Mini Drip: Chemex Roaster: DOMA
Posted Thu Mar 7, 2013, 3:16pm Subject: Re: What's going on here? Can't refine Chemex?
Netphilosopher - I'm not sure what you said. Lots of technical jargin! I think you were saying to pour at the same rate it extracts?
Micvog - I will try that, though it seems quite fine! Today when I brewed 45g:710mL twice (for guys at work), it turned out really well! Grind was at 9.5/12 (to the right side). And it seemed to get pretty clogged up after the second pour for some reason. Took about five minutes!
Posted Thu Mar 7, 2013, 5:30pm Subject: Re: What's going on here? Can't refine Chemex?
uRabbit Said:
Netphilosopher - I'm not sure what you said. Lots of technical jargin! I think you were saying to pour at the same rate it extracts?
Micvog - I will try that, though it seems quite fine! Today when I brewed 45g:710mL twice (for guys at work), it turned out really well! Grind was at 9.5/12 (to the right side). And it seemed to get pretty clogged up after the second pour for some reason. Took about five minutes!
Lee_M has a point - make sure your initial pour temp is the same.
On the tech jargon:
Delivery Rate = the rate at which you deliver the water.
Percolation Rate = the rate at which the dissolving coffee drains through the grounds.
Contact time - you do know what this is, right? It's the time that hot water is in contact with the grounds.
Now, the difference between brew methods may be part of the issue.
A true percolation means that fresh brew water goes into the top of the grounds, at about the same rate that coffee is draining out the bottom of the grounds. In between these two things, hot water is dissolving solids from the coffee grounds.
This is different from immersion (aka infusion). That method is like tea: you put the coffee together with water for a time, then you remove the coffee from the grounds.
The two methods require a different calculation for calculating "extraction percentage" (aka extraction yield).
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
uRabbit Senior Member Joined: 15 Jan 2013 Posts: 50 Location: Seattle, WA Expertise: I live coffee
Espresso: AeroPress Grinder: Bodum Bistro, Hario Mini Drip: Chemex Roaster: DOMA
Posted Thu Mar 7, 2013, 5:59pm Subject: Re: What's going on here? Can't refine Chemex?
Brewing at 200ºF, always.
Okay, so what should the times be for contact? I have been doing 45-sec blooms and 1-minute pours, resulting in 3-3:45 total brews (contact time). I guess this would be immersion?
So, I should be blooming, and then pouring for the remaining 3-3:45?
Posted Thu Mar 7, 2013, 6:19pm Subject: Re: What's going on here? Can't refine Chemex?
uRabbit Said:
Brewing at 200ºF, always.
Okay, so what should the times be for contact? I have been doing 45-sec blooms and 1-minute pours, resulting in 3-3:45 total brews (contact time). I guess this would be immersion?
So, I should be blooming, and then pouring for the remaining 3-3:45?
What you should be doing will be open to a very wide range of opinion.
What I do that works for me when I do a chemex:
-Fairly coarse grind (on the bodum bistro burr grinder, one to two marks finer than french press. Yes. that coarse. On my Lido, it trends toward 2.5 or so) -I do an initial bloom of about maybe 30 seconds. -Then, pour in batches, going for adding water just as the level draining reaches the top of the grounds. I think this means that I pour in dollops every 10-15 seconds or so. Some people will really fuss about pouring in circles and agitation, etc. Maybe this makes a difference for you, but it doesn't seem to make a difference for me. -When I bother to time it, the last dollop is going in somewhere between maybe 3:30 and 4:00 - or about 3:00 past the bloom , and it finishes dripping (for the most part) maybe, I dunno, 30 seconds or so later?
and make sure not to fill higher than the level of the grounds themselves. This takes some practice! Any water above the grounds will simply go out the sides without brewing the coffee and your final cup of coffee will lack sweetness as well as fullness. You can start and stop pouring as long as you keep some water in the grounds during the process.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
uRabbit Senior Member Joined: 15 Jan 2013 Posts: 50 Location: Seattle, WA Expertise: I live coffee
Espresso: AeroPress Grinder: Bodum Bistro, Hario Mini Drip: Chemex Roaster: DOMA
Posted Thu Mar 7, 2013, 6:48pm Subject: Re: What's going on here? Can't refine Chemex?
Interesting! We are headed out the door right now to go grocery shopping, but will be reading and watching those when we return.
More questions, however: - So, all your pours are pretty much equal to your bloom pour? But if you're pouring just as the receding level reaches the top of the grounds, doesn't that mean that you're adding water higher than the grounds? So confusing. >.< edit: The video answers this. :) - What is your typical total brew time? 4:30-ish?
Thanks so much for all your help! I really try to be a min/maxer (<-- gaming term; hope you understand!), and getting the occasional sour cup is just not acceptable to me. :D
Posted Fri Mar 8, 2013, 8:54am Subject: Re: What's going on here? Can't refine Chemex?
uRabbit Said:
Interesting! We are headed out the door right now to go grocery shopping, but will be reading and watching those when we return.
More questions, however: - So, all your pours are pretty much equal to your bloom pour? But if you're pouring just as the receding level reaches the top of the grounds, doesn't that mean that you're adding water higher than the grounds? So confusing. >.< edit: The video answers this. :) - What is your typical total brew time? 4:30-ish?
Thanks so much for all your help! I really try to be a min/maxer (<-- gaming term; hope you understand!), and getting the occasional sour cup is just not acceptable to me. :D
I'm starting to suspect that the bloom is really just to get the CO2 out of the picture so that the proper soaking and dissolving of the solutes, as well as decent percolation, can happen. If I just start going with the pour on fresh coffee (doesn't make much of a difference on older coffee) the bloom causes the grounds to float in a big foamy mass, and the water drains out rapidly before it can contact and dissolve enough solids. The first stuff going into the cup is weak.
I've experimented with cold blooming the coffee, with pretty good results. When I say cold, I mean room temp or so - equal amount of water as coffee mass (on 25g coffee, I use ~25g cold water). This is sufficient to off-gas the grounds. Then, I can go ahead and start the hot pour, but I do seem to need to add back the bloom time to get the desired strength and flavor characteristics.
Some people have had good luck using cold blooming with the Brazen and the Bunn HG Phase Brew (similar machines, more features on the Brazen including pre-infusion/blooming cycles).
What you're trying to do with a pourover is manually emulate what an auto drip machine does, but add in the bloom step. Most economy Auto drip machines are designed to deliver brew water at a constant rate, and the best ones are usually set up to deliver this water over approximately 3-4 minute period. Physically, you can't do this (imagine dribbling the brew water at a constant rate for 4 minutes) but you emulate it by pouring at a piece-wise, approximately constant rate - and you use the percolation rate as a guide.
On the Auto Drip machines, since the delivery time and rate are basically fixed (though with the boil-and-bubble type, think like the old Mr. Coffee technology, this can be adjusted/hacked by changing the temperature of the reservoir water), the only thing you really have to figure out is the proper grind that creates the correct percolation to match the delivery rate.
Too coarse, and the brew water goes through without enough time to dissolve the coffee.
Too fine and the water is delivered faster than it can percolate through the grounds. Some of the brew water goes down the sides of the filter without contacting the coffee grounds much, the rest is pooled and crawls through the coffee grounds, increasing the contact time.
Pourovers can be challenging, frustrating, and fussy, but they can be a lot of fun.
(so, what type of character do you usually play, and what game? ;) It's been years, but I know what you mean)
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
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