Archive for February, 2007

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.

retro

The first leg of my espresso tech training started out a the American hub of Astoria, the General Espresso & Equipment warehouse and showroom in Greensboro, N.C.  These folks are the center of the Astoria and Wega espresso machines in North America.  The Astorias have a reputation for reliability and low maintenance, and coupled with a reasonable price tag they fill the primary criteria of many an independent coffee shop owner.  With a heat exchange brew water system they may not be the envy of many cutting edge wavers on the fringe of the specialty coffee industry, but MOST coffee shop owners use that extra $2,000 on other essential business expenses.  That is where real life hits you, in the pocket.  The result is that thousands of these machines are spread across the land (and other similar brands), and these are usually what most folks are likely to get their drinks from.   Pictured above is the new but retro styled Rapallo, a shimmering old timey replica with the groups on the outside.

The training involved two days, the first covering a breakdown of traditional machines, and the second day concentrating on superautomatics.  I suppose if we can’t get an army of teenage mutant ninja Baristas trained up, the least we can do is make sure they can make a half decent shot just by pushing a button.  We set this thing as close as we could to perfect, and let me assure you, these will not replace the practiced hand of the True Barista who has learned their craft, but it will put mochas and vanilla lattes in the bellies of a culture that is starved for culture.

pistons

The superautos are a marvel of engineering.  These two pistons swivel into place after the internal grinder delivers their load of grounds into a cylindrical chamber, and the shower screen pushes up from the bottom.  Espresso squeezes out at the top and is directed to the external spouts via the white tubing.  The churning action created by it’s travel in the tube creates a very homogeneous colored crema on to of the shot with no visible flecking no matter what grinder setting you use.  Doses and water volume are adjustable in the programing mode, and all settings can be downloaded to a memory card and transported to other compatible machines.

One traditional machine that was in for repair was this Argenta that had been subjected to water softener abuse.  If you have ever had to reconstitute your water softener you will remember that you must fill it with salt pellets, flush it clean till the water coming out has no more salty taste, then open the line back into the espresso machine.  In this case, the service technician omitted the flushing stage and just hooked up the espresso machine with salty water.  I believe there is a law suit pending.  Imagine, if you would, an Italian accent issuing the phrase, “Holly shit!”, and it will be just like you were there.

I will have more training updates as I receive ESI training and Fetco, and what not.  So far it has been a great deal of fun, and quite the adventure.

Back with Beans

After a short bloggin’ pause, (and a forced DSL upgrade) I’m back with some green beans. The folks from Stockton Graham & Co who were kind enough to sponsor our little Soy Challenge got cozy enough with me to offer me a job as their equipment tech. All these years as a part time Barista, I was never presented with an opportunity to actually make a living in the coffee industry (Barista does not pay much). So now I have left the fast paced life in an engineering firm producing autocad drawings for a leisurely life basking in beans and espresso. Plus I’ll be traveling to some interesting places for training and events and what have you.

If you have recently checked out James Hoffman’s blog, you will notice his beautiful up close photography of a gigantic coffee been, a breed of Arabica called Maragogipe, or like he spelled it, Maragogype. The “Elephant beans” are just huge. My first day on the new job they had me working in the roasting room, mostly just watching the coffee being roasted. I noticed a sample bag of some green beans that were the size of roasted beans. Since they puff up about 20% bigger when roasting, I thought this must be the legendary Maragogipe. The label confirmed this for me. These are a Colombia grown coffee from the “El Boton” estate. We will be cupping it next week, I hope it has big flavor too. Here it is pictured next to an Ethiopia Harrar.

elephant bean

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