Why don't pros use the WDT? More advanced distribution techniques? - Page 6

#51: Post by **Rainman** » March 16th, 2007, 9:37 pm

I do live in the southwestern US (avg relative humidity is 4-5% during the dry parts of the year at the highest temps of the day, and upwards of 35% during the coolest times- except during the monsoon season; that blows the entire humidity curve, but accounts for just a few weeks of the year). I think relative humidity plays a bit part in some of this, but I'm sure the bean itself (and whatever storage container people use) may be an overriding factor in containing the essential oils and other volatile compounds in coffee beans. From most of what I've read and heard, these compounds are fairly sensitive to environmental conditions (whether via heat transfer during roasting or humidity/lack of humidity during storage). Not sure what you mean by "coffee cooled by water"?

Andy, can you clarify?

Ray

#52: Post by **AndyS** » March 16th, 2007, 9:46 pm

Rainman wrote:Not sure what you mean by "coffee cooled by water"

Some commercial roasting operations cool the beans at the end of the roast with a water spray. If properly metered, the water evaporates and doesn't significantly affect the moisture content (MC) of the beans. If too much water is used, however, some liquid water remains and obviously raises the MC.

#53: Post by **Rainman** » March 16th, 2007, 10:13 pm

Then what do you think can explain the difference in my grind settings? Somethings definitely up, there. I'm a complete amateur at this, so any words of wisdom are most useful to me. I know what I like, and have been reasonably successful within the confines of my home environment for several years using a variety of different technologies (by my tastebuds)- but it's probably a far cry from doing this sort of thing professionally. I think Teme alluded to this above talking about overanalyzing these sorts of concerns, which is very easy to do when each of us are sitting at home (in an uncontrolled environment) analyzing our own shots and reporting our findings here. I'm willing to bet that some of you guys would generate some bitter-beer faces tasting my espresso, but to me they seem pretty good (I honestly don't know). I think because of all of the variables involved, the only real way to figure out if we're on the right track is to travel around a bit and sample good espresso elsewhere (funny, but it's usually in colder, coastal cities where it's very cloudy and rainy)- I've never seen more espresso machines in operation than at gas stations in the state of Washington- here, in Tucson, we have Bunn coffee makers at best!

Ray

#54: Post by **another_jim** » March 16th, 2007, 11:18 pm

The weird thing is the difference in pour times I'm getting between my i-Roasted stuff and some of the Black Cat blend I ordered from Intelligentsia; the grind setting on the Kony is a little more than a 90 degree turn of the adjustment collar for the latter. I know it's like comparing apples to oranges, but I don't remember having anywhere that big of a difference in grind settings between those two coffees w/ the Rocky to produce the same pour times (maybe just 2 or 3 clicks). Mostly, I think fluid bed roasters just dehydrate the bean more than professionally drum-roasted coffees do- at least that's been my observation.

Actually a false conclusion from observing the finer grind required by air roasted beans. The moisture content in fast roasters (like most air roasts) is slightly higher during and just after first crack, when the beans hit their "glass phase," where the cellulose acts like a liquid and the bean expands rapidly. This creates a slightly softer, less brittle bean out of faster roasters. So a finer grind is required to get the same quantity of fines (it's the fines that regulate the flow).

Very soft beans, like monsooned malabar, require ultra-fine grinds, while some aged Sumatras are so soft that one can't get a good pour from an SO shot even at the point when the beans stop feeding. Ultra-high grown beans, on the other hand, tend to be more brittle, and require coarser than average grinds.

#55: Post by **another_jim** » March 16th, 2007, 11:28 pm

I'd love to have a way to test your questions on the effects of the WDT. I wonder how one would go about testing that? Where's Jim Schulman when you need him?

The discussion so far is on track -- stirring any mix of fine and coarse particles will tend to settle the fine ones at the bottom (salt in the peanut jar is an example). WDT presumably works because it anticipates the fines migration that happens in ordinary prep pucks, thereby reducing the window when cracks form.

The simplest and most convincing test would be with a laser particle sizer. Remove samples from the top and bottom of a non-wdt puck, and the distributions should be close to the same. Remove samples from top and of a wdt puck, and the fines will all be at the bottom.

Barring that, the indirect test is to presuppose that the fines control the espresso flow (this is the current idea in the literature). If most fines have migrated in a WDT puck, removing the top half won't much affect the shot flow; whereas in a non-wdt puck, this procedure would produce gushers. Start with wdt and non-wdt grinds and packs that produce equal shot flows. scrape off equal weights (say 5 to 8 grams) off the top of each, and time the resulting flows. If WDT works by anticipating the fines migration, it's flows will be a lot longer, close to the intact puck's, than the non-wdt pucks mistreated in this way.

#56: Post by **AndyS** » March 16th, 2007, 11:33 pm

another_jim wrote: The moisture content in fast roasters (like most air roasts) is slightly higher during and just after first crack, when the beans hit their "glass phase," where the cellulose acts like a liquid and the bean expands rapidly. This creates a slightly softer, less brittle bean out of faster roasters. So a finer grind is required to get the same quantity of fines (it's the fines that regulate the flow).

I wonder if this is the phenomenon behind the unusual requirements of Gillies espresso beans, which seem to require an ultra-fine grind. Something about Gillies's Lilla roasters?

#57: Post by **RapidCoffee** » March 17th, 2007, 12:08 am

another_jim wrote:The simplest and most convincing test would be with a laser particle sizer. Remove samples from the top and bottom of a non-wdt puck, and the distributions should be close to the same. Remove samples from top and of a wdt puck, and the fines will all be at the bottom.

I actually suggested this (somewhat jokingly) to Teme in a PM. Hmmm... would it be possible observe the migration of fines while stirring in a glass container? Certainly be a lot easier than slicing pucks...

#58: Post by **another_jim** » March 17th, 2007, 1:05 am

AndyS wrote:I wonder if this is the phenomenon behind the unusual requirements of Gillies espresso beans, which seem to require an ultra-fine grind. Something about Gillies's Lilla roasters?

I noticed it on their 5 points; I assumed that it was because they had an aged indo in there (it would explain the price they are charging, and the nicely complex low end tastes). If it's also the case for their other blends, then it could be the roaster.

It's easy for me to tell on my own roaster, since I frequently get green and roasted samples -- my roast always need a finer grind, and it's so regular (0.35 on the 10 point scale on the Versa), I usually can figure it out without any test shots.

#59: Post by **AndyS** » March 17th, 2007, 8:18 am

another_jim wrote:I noticed it on their 5 points; I assumed that it was because they had an aged indo in there (it would explain the price they are charging, and the nicely complex low end tastes). If it's also the case for their other blends, then it could be the roaster.

I noticed on one of their "Dark" blends and also their Espresso do Brasil (no Indo).

#60: Post by **LeoZ** » March 24th, 2007, 7:08 am

Abe Carmeli wrote:This is only an observation after judging three barista championships in the past 12 months. During the competitions and the workshops that precede them, judges spend days in close quarters with the competing baristas and some national champions who work in the workshops. It is my impression that the secret ingredient in their barista technique is updosing. 18 grams in a double L/M basket is considered normal by most of the baristas I worked with. At times the impression of the shower screen screw on the spent puck is so deep, it forms a small crater. The updosing is so severe, that in all three competitions the L/M technicians needed to replace the dispersion screen halfway through the competition on all the machines. The baristas will go up to 19 & 19.5 grams at times. There are a couple of reasons for doing it, one of which is compensating for less than perfect distribution & tamping. If the machine can take it, updosing evens out deficiencies in canted tamps, and hurried up distribution. It has to do with the coffee being pressed evenly down by the shower screen. We did some experiments with canted tamps on updosed shots: The spent pucks looked perfectly level. Because of that, judges pay very close attention to leveling the shot and no longer take a leveled puck after the shot as evidence of a good tamp.

Funny thing is, low dosing, that is 13-14 grams, will also produce a shot free of channeling even with less than perfect distribution, but for a different reason. Such shot pucks end up being a dough like mesh during the shot with self healing properties which close any gaps during the shot.

Overdosing however can be severely punishing when it comes to taste, and it is all coffee dependent of course. I suspect that the great number of imbalanced shots we got in the GLRBC has to do with overdosing.

well doesnt that go against everything jim schulman taught us with his article!

what kind of flavor profile is 'award winning' by judges? is it anything close to what european espressos would taste like? i get quite different flavors from the 2 techniques.