Grind particulate sizes

I have been putting a lot of thought lately into the simple task of brewing one cup of pour over coffee. I have always been know as the “coffee guy” at what ever job I was working. My last job was in an engineering firm, (working with engineers, not engineering myself). The coffee was provided by a large company know to many an office cubicle dweller by their distinctive initials that always put the word “standard” in my head. By free association, I am then mentally transported to the men’s room in my mind, staring down at the logo for the urinal manufacture . I think it is because the initials have both an S and a D, which makes me think of Standard. So I have always made my coffee with my beans, one cup at a time in a pour over. Everybody called me the coffee guy.

So now that I working for a coffee roasting company, I am still making my coffee one cup at a time. But it is not so simple. Sometime it is great, sometimes no so great. I have been trying to figure out what makes it better, why the results fluctuate.

You frequently hear that you should use the right grind for the brewing method, but what I have found to be very significant in the pour over brew is that you use the right grind for the volume of coffee you intend to make. If you simply use the “cone filter” setting on your grinder, sometimes indicated with a little icon of a cone filter, and then try to brew a single cup with a little Melita cone, the water will pass through with a shorter dwell time than it would if you were making four or six cups. The single cup needs a finer grind because the smaller volume of water takes no time at all to pass through the grounds. My grind is set so that the dwell time is about 1 minute 30 seconds. (That is counted after the one minute of bloom time.)

The second important factor I will address in this post is the level of agitation required to extract only the compounds contributing to a pleasurable cup of coffee, and leave the ones that produce an over extracted flavor. I have read many posts on coffeegeek that refer to stirring the slurry, some calling for as much as 30 seconds or more of whirlpool action in a french press. I was lambasted on one thread, (and I think I was accused of peddling snake oil), for suggesting that you can control the level of solids that dissolve into your coffee by how much agitation you introduce (I was also told there was no need to bring physical science into the discussion). Less agitation, I claimed, will achieve a more complex and desirable flavor, and more agitation will flatten the taste.

Let me go through the current state of my pour over technique for one cup of coffee. The measurements I use are in one hundredths of a pound, because the scales I use don’t do grams.

For a 12 oz cup of coffee I start with 14 oz of water, and use .050-.065 lb (depending on the bean), the excess is absorbed by the grounds.

-Water from the kettle about 30 or 40 seconds after boiling is poured on, just enough to soak the grounds in the cone to bloom.
-After a minute of them soaking, pour the remainder of the water slowly in such a way as to cause the least amount of churning as possible. Let the water seep all the way through.

The result should be a crater of grounds left in the cone that very evenly coats the sides. If you have poured in a way that caused too much agitation there will be bare spots, or worse, all or most of the grounds will have fallen to the bottom. The most amount of over extraction happens when all the grounds go down to the bottom because the contact time between the water and grounds is the greatest.

When I made a larger amount of coffee in the Chemex with the same grind, the dwell time increased to four minutes or more, and at that fine of a grind there was just too much extraction for a great cup of coffee. So I figure I need to adjust the particulate size of the grind proportionately with the volume of water to be brewed in order to maintain the same level of extraction; more water, courser grind, less water, finer grind.

  1. Great writeup Phil. I’ve never been a convert to gravity (man thats funny on a few levels). Always choosing my press wherever I go. If I was ever to experiment with filters though I’m printing this baby out for reference!

  2. If and when I ever pass through your neck of the tall pines, I will brew you a cup with my trusty gold filter gravity feed. There is a whole technique just for that, and at a much finer grind than French press you can cut the fines in half.

  3. I do think some agitation is necessary, or you end up with a very under-extracted cup.

    Of course, if you’re blessed and not doing this for commercial purposes, the same rule does not apply.

    It’s easy enough to control the flow rate so the grounds do not reach too high up in the filter. If that happens, you get an un-even extraction. The coffee in the bottom of the cone is still being extracted while the coffee that’s stuck to the walls up towards the top have barely been extracted at all.

    This does not mean severe agitation.. just enough to encourage every coffee particle to contact water. (if you don’t, clumping can lead to dry patches.. and that means under-extraction)

    Just my $.02.. from the Alternative Brew Methods article in B-mag a few months back.

  4. Yes, the more detailed explanation of the technique includes:

    -the minute of bloom time should provides moisture to all the grounds, and the subsequent soaking needs to churn enough to prevent clumps

    -pour slow enough to keep the water level at or blow the maximum desired elevation

    -the slow pouring provides all the gentle agitation needed

    -as the water retreats from the apex, the grounds that stick to the sides maintain a properly decreasing ratio of submerged grounds to water

    But all this minutia is just the kind of thing that got me flamed on CG, I mean geeze, somebody starts a thread about how to get specific results from brewing, but get into detail about the basic psychical science and suddenly your accused of blowing hot air.

    But you get the picture. I haven’t seen this B-mag article, I should get a copy.

  5. No you shouldn’t. I wrote the Melitta portion. If you want the info on FP and Clover, then by all means, get it.

  6. Vac pots… vac pots…. That’s the future or maybe it was espresso, I forget again.

    I like to see tweaking that’s flavor based but I always say test everything and challenge any standard because it is often specific to roasts and coffees used.

    my apples and your oranges… may both taste great… or I could have much better apples than your obviously wrong and not so hip not quite 3W oranges.

    Jason y Phil, I challenge a blogger take all review and comparison with vac pots, clover, aeropress, french press and any other sensible device that can be mustered…

    best quality drip discussion? Pros and cons of each method and ideal coffee styles for each? Good fodder, no?

  7. I certainly don’t mean to suggest that a little plastic funnel is the “Alpha and the Omega” of extraction. I go through phases of what I like best at any given time of year. Sometimes it the plunger (that is Australian for French Press), sometimes the Melita, or the knock-off “gold” filter (it is taking on a non golden patina lately). Many days it is good old Mr. Coffee. If you pour 3/4 of a cup of 203 degree water int the basket at the beginning of the cycle it much improves it’s performance.

    So I do not think of one method as producing a better profile than an other method, just a different profile. Within each discipline there are certain taboos of science that, when observed, will target the most generally agreed upon best tasting solubles. There will also be tradition based on legend, or habit born out of O.C.D., or pure nonsense.

    What I am all for is weeding out the real “Snake Oil” from the tasty brew.

    If you suggest a collaborative, cross-net, multi coffee brew technique flush out project, then lets get a list together and divide the duties. We might end up with a nice spread sheet of do’s and don’ts.

  8. “collaborative, cross-net, multi coffee brew technique flush out project”
    Must come up with a better acronym but hey, why not ‘with our blogging powers combined’ we do a little constructive comparison of multiple drip brew methods? I can think of at least two more bloggers who might be down for a little bangin exploration of methodologies…
    Not a set of rules but a what can we find type of project…

  9. I’m in.

    I must confess a certain pre-existing bias I have, though. I already think Vac-Pot is king, but I’m willing to experiment anyway.

    Full submersion with timing control and minimal sediment = excellent brew method.

  10. I’m switching to coffee-chew. A semi-find grind between lip and gums, oh yea. Submerged, partially agitated, 100% sublingual hahaha. :o)

  11. Don’t forget the spit cup.

    • seasun4
    • April 4th, 2007

    Can I dig this and some other postings?

    Have you seen the drip-style coffee brewing process widely used in Japan and Korea, which can be a good help for you as to how to pour water with less agitation?

  12. What do you mean by dig? If you link to the original you repost, if that is what you mean.

    I don’t think I know the Japanese and Korean technique you are referring to. Do you have a link to an explanation of that?

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