Friday, December 23, 2005

espresso theory 201

there's an ongoing debate among espresso enthusiasts about dosage amounts of espresso in the portafilter. many folks believe that a slight 'gap' should remain between the top of the tamped espresso and the group head difuser screen. this allows water to sort of pre-infuse the espresso evenly and helps eliminate channeling (where water finds the path of least resistance through soft spots or 'channels' in your packed espresso), off-center extraction and the like.

the flip side of the argument calls for overfilling or 'updosing' the quantity of espresso in the portafilter--perhaps bypassing the tamp altogether, as the italians are historically known for doing--and simply relying on the greater quantity of espresso in the portafilter basket to do the work of fighting channeling, evening extraction and ensuring an overall delicious shot of espresso.

there's more.

take into consideration extraction times with different doses of espresso. any good barista will tell you that a good shot rule is comprised more of sight than of seconds...so long as you're getting that good 'tiger-striping' in the pour as your espresso honeys out of the portafilter then you're in good shape. but as soon as the color begins to pale (what many refer to as 'blonding') then it's time to shut off the shot, so to speak. this can happen as early as 18 or 19 seconds (some even claim good tasting shots at 16-17) or can last well into the high 20's and some even say they get good striping into the low 30's. the point is, the visual cues should outweigh the timing factors. nobody closes their eyes, hits a timer and waits for it to go off before stopping the espresso pour. a great barista uses sight, smell, even the 'feel' of how a pour is going to determine greatness in espresso shots. (and obviously, all those factors are trumped by taste.)

yes, there's more.

what are some of the things that can cause the difference in color/time? and what might be one of the factors in deciding on an appropriate dose? [by the way, this is all just the set up for my theory...it's all generally accepted barista theory i'm laying down here.] well, assuming the technological field is leveled--that you're using a temp stable machine with good water--and assuming you're skilled enough to know how to use the machine, one of the last, greatest factors to account for is the bean(s) themselves. i say 'bean(s)' to mean whether one is using a single-origin espresso or a blend of beans for their espresso...and of course, what mix of beans and in what quantities.

so here's my theory.

since there are too many factors to account for when talking about an espresso blend (i believe there are some 1600 types of beans combinations available for blending into espresso) i'll limit my theory to single-origin espressos, which are getting much more attention these days.

everyone knows that the espresso method is a far superior way to detect a coffee's true taste profile. (it should be noted for non coffee nerds that espresso is not a type of bean nor a type of roast, but a method of preparation. another post.) anyways, running shots through your espresso machine will highlight the guts and glory of a bean, tell you a lot about its roast and, in my theory, present some significant evidence as to its method of preparation, meaning how the bean was processed in its country of origin. my theory is that, all other things being equal, a semi-washed or natural (dry) process coffee should be able to hang out longer in the portafilter before blonding, before the shot goes awry. further, i believe the processing method may also be a big enough factor to surmount dosage differences. think about it. in dosing you're basically talking about a difference of three to maybe five grams of espresso. yes, i know, that small amount can make a huge difference. but it may not present as big a difference as a dry will show versus a wet.

it's all about the mucilage. a wet processed coffee basically strips the bean from its cherry, gets 'washed' free from the mucilage membraney stuff that surrounds the bean, then gets tossed into a fermenting tank of water for several hours. that is a huge factor in how that bean is going to taste. a bigger factor, perhaps, than roast profiles, than dosing in an espresso machine, will, in fact, help shape and determine the roasting profile and the roast curve a good roaster will treat the beans to.

flip to the dry side. a dry or natural process eliminates the water fermentation tank and allows the beans to dry inside the mucilage and cherry before being hulled. so now, all that mucilage-ey 'stuff' (the stuff of legends, maybe) is drying onto--into--the bean. that is huge. those of you who cup coffee seriously know the difference between a wet costa rica and a dry sidamo. yes, they are from differing regions with inherent taste profiles specific to their geography and 'terroir.' but there is that other, almost unspoken but definitely noteworthy, difference in mouthfeel, in gaminess, in leave. it's what can account for the oddity of a timor maubesse tasting more like a guatemala than an estate java or sulawesi. the timorese have been wet processing their coffee for maybe a decade, giving their product more snap, more crisp acidity than its nearest neighbors, the brooding, mysterious and sludgy sumatras.

it's another fold in the ongoing theory debate over espresso. the longer i cup coffee the more i am convinced that processing can affect flavor every bit as much as terroir, variety, yes, even roasting and dosing. this concept naturally--maybe definitively--manifests itself in the intense parade grounds of the world of espresso.

let me just iterate here that mucilage or its lack on/in a bean does not trump the variety, geographic character of the bean itself. but a bean's processed method can make some significant differences in the cup. everyone talks about how the centrals (central america) must be washed as though it's a foregone conclusion that those beans will only stand up to wet processing. but maybe it's a self-fulfilling prophecy. maybe no one tries to dry process the centrals anymore because they just take it as received wisdom and don't bother to test and retest the settled questions. maybe that will be the next frontier in boutique coffees.

there are some really killer blogs and enthusiast sites that are theorizing and debating much more eloquently than i can. i encourage you to check out some of those sites: godshot, i am a green bean, portafilter, coffeegeek and viva barista are all great sources of info.

happy hunting. and bring on the comments. it should be noted here also, at least for posterity's sake, that i don't currently have the equipment/beans to test my theory; so it's also a call for someone to look at this theory and test it. i currently have a super auto home machine that doesn't get me where i want in terms of in-depth testing.

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