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.