Questions

My brain is full of questions at the moment, and I thought I’d post (vent) some of them on the off chance that anyone reading them has any answers.

- Chaff in ground coffee: is there an easy way to get rid of it?  Does the coffee taste very different afterwards? The roll and blow method is quite messy.

- Should coffee definitely spend time in reposo, or are we just roasting super fresh crop coffees wrong? I’ve tasted coffees that have been described as being too fresh (a bit green) and have seen that taste drop back over a few weeks.  Is this a raw product thing or a roast profile thing?

- Is there any solid research/explanation of why we bloom when we brew pourover? A bit like spinning the tamper to polish, this is something I started doing because other people started doing it.  I am sure there is some solid thinking behind blooming (certainly compared to the spinny polish thing) – I just wonder if much formal work has been done.

- Could you fit some form of flow restrictors into pouring kettles? (I’ve had interesting data and flow restriction results wedging a k-type probe down the front of my buono spout.)

- Speaking of pouring kettles, is it me or is it really easy to brew under temp with them?

- Seeing as how chocolate has a similar model to coffee, more so than wine, should we look at it a bit more for inspiration? Or is the communication and spread of knowledge and genuine information about speciality chocolate (I am sure they have a better term) behind that of coffee?

- Cupping:  what temperature should the liquid be at the start of brewing?  at what point in the cupping brew time should the extraction reach the 19-20% mark? Do coffees taste better as they cool because they are continuing to extract? Should you start temperature influence when you break?  The Uber makes me wonder about the temperature thing.

- Honey process.  This is clearly a much tastier name than pulped natural, how long before everyone starts using it?

- Any idea how I can organise the Naturals Debate post into something a little easier to digest?

There are many other questions, but I am not complaining – questions are the best bit of coffee.

39 Comments

  1. Aww. you stole my flow-restrictor idea!

    I was going to try to weld some sort of adjustable valve on the neck of one of my pouring kettles. Closer to the ‘pot’ than the spout.

  2. James, When brewing with pourover, I have found that the bloom phase reduces floating dry clumps. Breaking up floating dry clumps requires either agitation or more water, which you may not want.

    Agitation is clearly up for debate. I don’t stir these days.

    On the other hand, there is only so much water that will fit in there(or that meets the brewing ratio).

    I don’t know that this counts as “solid research”, but it comes from brewing a lot of pouroevers.
    -Tom

  3. I worry that close to pot would mean that the reduce volume of water would lose heat quicker in the ‘empty’ spout.

  4. Thats a good idea nick. I’ve considered a rubber stopper, with a hole in it, inside the ‘pot’ and plugged into the spout.

  5. It is indeed very easy to brew under temp with pouring kettles and it is a pain to re-heat the water if you use the kettle only as a pouring device. That’s why I stopped using my electric kettle and just use the Buono on the gas stove.

  6. As far as bloom goes:

    Try coffee with or without a bloom – noticeable difference in taste. Try a 15 second bloom, then a 120 second bloom.

    It also helps release CO2, which messes with the interaction time the water has with the coffee. The more CO2 being released during the brew makes the drip have weird interactions – bubbles rising up from lower points of the cones, etc. Also, I’ve always been under the impression that CO2 blocks extraction, so releasing it with a bloom meant easier uniform extraction.

    I think you can have a good cup of coffee with or without a bloom, but the bloom helps standardize it better, and is easier to repeat.

  7. I’ve been practising with my buono and followed the guides at the barismo blog, where they emphasize on wetting all the dry grounds to prevent channeling

    But when I think of it I could just keep on pouring while the coffee blooms. Maybe it has something to do with the CO2 tescaping from the grounds. I often notice some bubbling while blooming.

    I imagine it works the same way as preinfusion in espresso, giving a more stable resistence against the water, forcing it to go through the grounds more evenly.

    Just my thoughts, nothing solid really.

  8. “I think you can have a good cup of coffee with or without a bloom, but the bloom helps standardize it better, and is easier to repeat.”

    Totally agree, bloom makes your result more repeatable.

  9. Oh great. Others saying pretty much the same thing. Just better and faster ;)

  10. Pre-infusion doesn’t necessarily work well in espresso, it can lock up fines mid-puck and lower resistance, screwing up the extraction. I guess it’s different in pour-over, but can be dependant on the grinder you’re using (whether it produces loads of fines or not).

  11. Re: chaff. I can’t remember any correlation between flavor differences and differing amounts of chaff. Has anyone tried “brewing” the contents of their chaff catch? I wasn’t aware that it really had any flavor to speak of.

  12. What about when you can control the pressure, like on a Slayer? Would that be similar to what’s going on in pourover brewing?

  13. In response to the chocolate point. I’ve been studying chocolate and coffee at the same time, and the models are far much more comparable than coffee to wine. The knowledge is there to be had for chocolate, it just is not in the public eye, and is not so heavily marketed, you have to activley seek it out. Or at least that is my experience.

    The elements involved in tasting chocolate gave me a better start to to tasting the flavour and complexities in coffee. I have since moved onto tasting wines… and pretty much everything else i can get into to help it along aswell :D.

  14. I’ve brewed chaff. It is not yummy, but chaff from a natural is a little better than from a washed.

  15. For chaff what about placing a wire mesh 2-3mm just before the filter (for example on the output hole/tube of the Guatemala)? Should let even a coarse grind through and stop the chaff.

  16. How is the honeyed process different than the pulped-natural process? I recently had Edwin Martinez’s Honey Michicoy from Guatemala, roasted by Barefoot Coffee. I didn’t taste a huge difference from a normal pulped natural, but felt like I should have. So, how’s it different? What makes a “honeyed” coffee?

  17. Speaking of brewing under temp with kettles, I began experimenting with my kettle at home to find what percentage of the brew time in my Chemex was receiving water in the 195-205 range. I hooked up a probe and began plotting the temp decay of various amounts of water over time. I found that even with a full kettle, the temperature dropped below 195 after 2 minutes.

    So, I decided to find a way to keep my kettle heating while dispensing the water. What I came up with was using a stainless braided water line (like an espresso machine hook-up) fitted with a 1/4 turn valve plunged into the kettle. After priming it, I am able to keep a probe in the kettle while simultaneously dispensing and pulsing the boil.

    Yes, the Uber would do better, but for an ex-roaster now teacher, this is a pretty decent set-up that allows me quite a bit of control.

  18. I understood the term „honey processed“ as a better sounding alternative to „pulped-natural“. Did I get it wrong?

  19. I was once told by Graciano Cruz that the pulped natural process was invented in Brazil to move big amounts of coffee dried on patios … what became known as honey processed coffee here in Panama and other CA countries is a method used for small micro/nanolots depulped mechanically or manually and dried always on african beds without using a drop of water … (we did a short video here: http://www.youtube.com/watch?v=OcLLtPXEkCI)

  20. Honey Process-

    Since we started sourcing from a variety of roasters, and seeing a wider range of producers, it certainly seems like more people are jumping on the “Honey Process” bandwagon.

  21. You didn’t mention anything about cheese snacks. It’s one of the hottest topics, really.

    Anyway, organizing the Naturals debate seems to be the smallest of issues. This posts bites off more than most can chew – it’s the shotgun approach and I am sure the comments will reflect this too. They already have. Since you asked for opinions

    Chaff in ground coffee: get rid of it at the sample roaster – neary impossibe to separate in the ground coffee unless you use sieves or vibrate-separate the coffee.

    No Reposo: unless you want coffee to be something other than a dried seed, it needs to be stable. I am sure you can use some interesting roast and brew treatments to create fantastic beverages from coffee in it’s transitional stages as it reaches a state of equilibrium (ie rested) but it will be awfully difficult to reproduce those results.

    Brew kettles: could help pour-ver techniques to become more repeatable and less technique sensitive with improved design, I agree.

    Chocolate vs Wine analogies: I don’t think chocolate is as similar as it might seems initially in substance. I think it is most useful because there are so few other analogies for bittersweet qualities in food and beverage. But as a process, they are so different in all respects, agriculture, physically, process…

    Cupping: Oddly as grounds settle they tend not to overextract the liquid, from my measurements . But I switched from bowls to taller cups because there is one big issue here: the way people put the spoon in the cup and remove it. It is amazing the turbidity from how some people put the spoon into the liquid! If you have finer grind, big spoons, and people with certain styles, they totall “stir” the cup even though they don’t go down into the grounds with the spoon. Turbidity leads to overextraction.

    Honey Process: Some would say it is different than pulp natural, but only in that they want to separate a raised bed drying of thin layers of coffee from the mass drying of pulp naturals, possibly on patio/ground, as it might happen in Brazil. “Miel” was the word used by Santa Elena Beneficio in Costa Rica, sold by Erna as Tarrazu Taparto, going way back. Now a lot of honeys are created using demucilagers and controlling the exact percentage of mucilage on the parchment, which is different than simply running coffee through an old style pulper and then drying it. They can be great, they can be dangerous, you can be rewarded, you can get burned, people need to decide for themselves what role these coffees can play for them. And with that last sentence, I wish the naturals debate did not start with a universal decree, but rather something more bite-sized and relative to each of us who use naturals, or PN coffees, or choose not to use them. I like dialectic antagonism but it can be more productive for people to respond by speaking from their own experience, about their own decisions and why they make them, rather than casting this upon everybody in ambitious statements. Maybe that is less interesting and ends up just like a internet poll in the worst case. So it was the source material for the Naturals debate that both made it inspired but also very limited, in my opinion…

    Tom

  22. Agreed that the models for chocolate and coffee are closer than are wine and coffee… but yes, they are still different.
    However, I was talking with a person in high-quality chocolate R&D last week, and his opinion was that chocolate is still very much behind specialty coffee from a sourcing and quality development perspective. Needless to say, he and I had a spritely conversation, ending on the optimistic note of the possibilities for chocolate to follow (somewhat) in the footsteps specialty coffee has blazed in the areas of direct sourcing, producer-partnership, transparency, and quality-improvement measures.

  23. My nana was ahead of her time with temp stability research. She knitted teapot covers (tea-cosies) which appear to have a positive effect on the pouring kettle too, providing an outer insulating layer to help the pouring kettle retain its heat throughout the process.

    We lag our boilers and water tanks to retain heat, so why not our brewing equipment (in a similar way to the Eva Solo covers)?

  24. I’ll give my home roaster and coffee enthusiast perspective

    - Chaff: Shake vigorously after roasting in a mesh drum. Wouldn’t it be great if the grinder could separate the chaff? I’m finding that I get a lot of chaff left behind in the top chamber of my Kyocera hand grinder, either because the chaff is electrostatically attracted to the plastic barrel or because the beans rub the chaff off in the narrow tube before being ground (or both).

    - Bloom: I figured it was to prevent the mess when the coffee expands above your cone or AeroPress… that’s why I started doing this with fresh home roast, out of necessity.

    - Flow restrictors: While your at it, make it an aerating flow restrictor, as long as it doesn’t drop the temperature too much.

  25. Try a bartenders spout maybe?
    A better quality one short pour at 10mL per second. I’m not sure how you would attach it in standard form, but I’m sure something could be made up quite easily.

    I’m assuming this is what you mean by restricting the flow?

  26. no reposo, adding to thompson: the fascinating thing about reposo is no one has ever explained it without just describing proper drying. ie. if reposo is stabilizing the seed, what is drying? if drying is stabilizing the seed, then what is reposo? the research seems to say that, if given moisture or heat or an abundance of oxygen, that seed is a viable germ, and hence respirating (bad). below 13%, it is not a viable germ. if the coffee is truly dry, stable at a percentage at or below 12%, it’s certainly good to be packed. if we’re talking shipping in jute, it’s another story, and much more nuanced to the particular origin.

    honey and pulped natural, adding to thompson: definitely not the same, but the increase in central american honeys lead to pulped naturals called honey. ie, true honey is not demucilaged, and pulped natural is demucilaged.

  27. As per TO and Ryan,
    I see what you’re saying there Ryan, but reposo is super important not just to arrival quality, but to a coffee’s longevity, including, and maybe even especially coffee packaged in material separate from jute (Grain-Pro, Vac-Pack). From my understanding, reposo is stabalizing a coffee in a more controlled environment than drying , creating uniformity of moisture levels from seed to seed. Vac-Packing a coffee without proper rest can lead to some funky cups.

    I agree on the chocolate thing, I’d like to see more dialogue on that front. As far as the chaff goes, it’s best to deal with it before grinding; although, I am generally clothed in little else than stray chaff from one place or another

  28. James,
    As per your question to the seasonal “overfreshness” of coffee:
    I was in Costa Rica cupping stuff that was less than a week off harvest. There were some wildly “fresh” notes on the table to the point where I was having a hard time discerning some character. Francisco Mena of Exclusive coffees cups 4,000 samples a year and said to me after the first couple rounds, “This will be really good in a month or two”, implying that the fresh harvested coffee needed to rest. From his perspective, at least, was that a bit of rest time for green helps with cup character and clarity. Just some interesting thoughts.

  29. Regarding organising your blogs. Well I was talking to my journalist flatmate about unrelated online blogs and the comment sections in some online newspapers. He was saying the best ones were when there was rating system in place for peoples comments. This allowed for more educated and/or productive comments that readers found most relatable to at the top of the list and not scattered throughout amongst the other random comments people are making. This creates a real arena for debate– the stuff people want to read is much easier to find– and is where online journalism gets the most exciting.
    Best examples I can think of are digg.com and youtube.com and some online newspapers…. I think nytimes.com has a good system like that. It can be just a simple thumbs up, thumbs down next to each comment. Youtube lets you change how you view the rating also.. ie: highest first, lowest first or newest first.
    Umm maybe you could add something like a “people in support of the article” and “people against the article” rating too… and create such lists etc etc… i guess there’s numerous possibilities.

    anyway hope this help spark some ideas.

  30. Installed the best I could find (suggestion welcome). Will give it a couple of weeks trial.

  31. chaff tastes dry and corn-like. can’t think of any way to sift or winnow it out without making a big mess… maybe we can re-think what we see as a “mess,” and call it “floor spice.”

  32. I immediately thought of doing plaster work. One starts with much less water than final to encourage wetting, waits, then pours in the rest. I do the same thing with chocolate milk. It makes sense for dry clump prevention.

  33. Please explain!?! – isn’t it simply to make for a more even and full extraction due to an effect similar to pre-infusion!?…

  34. Agreed! – reposo seems very important! – I have heard from many cuppers now, cupping super fresh crop, that they are simply not developed yet or pleasant at that point!…freshness is a tricky term in coffee! – when is the optimum time to end settling of the beans!? – I think this is an area, that could really make or brake a coffees quality and an area for further development and knowledge! – Ussually one month is sufficient I am told! – but I also think that this could be the bare minimum in some cases. In some cases it might just be what is really the most convenient period of time for the producers wanting to be able to finish harvest processing and push their production which is limited by their capacity! – therefore time becomes an issue for sale and income.
    It might be kind of like wine! – some coffees need to mature a bit more than others! – provided that they do get packaged in a sealed environment immediately afterwards to secure that optimum level of maturity and freshness.
    I have heard of only some controlled experiments with settling time. I guess it is a matter of taste when it all comes down to it, as with most things in this business. But I am sure settling is essential for a coffee to fully open up and to secure an even quality in a lot.
    The smell in the rooms where coffee is resting is quite intense! – coffee resting really gets parfumed and I am confident that important chemical reactions takes place in the center of those tulhas.

  35. Regarding wine, chocolate, etc. analogies: Why look outside of coffee for inspiration? Isn’t coffee inspiring enough on it’s own? And why do we need a “model” at all? Why not work from first principles to develop and understand coffee on it’s own terms?

  36. about flow restrictor: i personally do not find this necessary with these “narrow mouthed” kettles. have other than buono and restricting the flow into dripping is a wrist thing. flowrestrictors might work better with wide mouthed ones though. .

  37. The extra sweetness of the honey process in combination with the clean aftertaste and the ecological approach in terms of less water consumption are in my opinion important criteria for more mills starting using it. We already have two estate coffees honey process in our line and we are waiting for one more to come.

  38. An aside to temperature of pouring kettles: Why does everyone talk about water temperature rather than brewing temperature? Surely the temperature the coffee is brewing at is the important measure, yet I never see any references to this. Assuming for simplicity (yeah, I know) that you want brewing temperature to remain constant throughout, this would require a fairly high strike temperature (as they call it in brewing when adding initial water to the mash tun) to bring the grounds and filter and brewer up to temperature, then water temperature close to the required brewing temperature to raise the level in the brewer, and then when topping up the brewer a higher water temperature to counteract heat loss. Has anyone done anything like this? Are we assuming that the current brewing temperature profile is better than a constant temperature (maybe like a lever machine pressure profile)?

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