cafeIKE wrote:What's interesting with circles is the open area between any 3 circles changes as the square of the radius ratio, but the total open area changes linearly for a number of circle to fill a fixed distance.

Intuitively speaking this seems wrong to me because AREA does not change linearly (it changes by a square). In my silly example, there is an area rather than a linear distance and in puckology terms we would be going 3D...

Of course this is just my intuition and I have not done any modeling or calculation but I would imagine it goes kind of like mesh screens might if you were to vary the wire size as well as the grid lattice spacing.

back in the real world, the sticky part is that every particle is irregular so close packing spheres is a "rough" approximation at best

cafeIKE wrote:...the burrs are spaced about 0.25mm and 1 gear wheel tooth changes the spacing about 4%, but the net extraction time could change 10%, 20%, 50% depending on ....

So it would seem that the behavior is not linear with burr spacing. Considering the tiny amounts of adjustment we make this probably shouldn't be surprising. Instead of talking percentages, consider expressing the same thought using microns for burr spacing...

Mental Exercise:

Lock yourself up in a dark room and write down one clearly true thing you have learned from this thread that will benefit your espresso making skills.

ken

Plus we are not dealing with a planar problem but with a 3d non-spherical jagged particle. So the packing problem may be much higher than best case sphere packing in geometry.

Ken Fox wrote:Mental Exercise:

Lock yourself up in a dark room and write down one clearly true thing you have learned from this thread that will benefit your espresso making skills.

ken

Is the locked dark room supposed to help this exercise, or make it more difficult? I have trouble writing in the dark.

RapidCoffee wrote:Is the locked dark room supposed to help this exercise, or make it more difficult? I have trouble writing in the dark.

The darkness will help to clear the mind. Locking the room is really only necessary if you think you might be a danger to yourself or others.

It will only be a challenge should you find something you need to write

ken

JonR10 wrote:Intuitively speaking this seems wrong to me ...

Consider the case where the radius ratios is 1:2. The areas change is 1:4. However you need twice as many of the 1r as the 2r to fill a fixed distance, hence the total is 1/4 x 2 = 1/2, the same ratio.

Ken Fox wrote:Mental Exercise:

Lock yourself up in a dark room and write down one clearly true thing you have learned from this thread that will benefit your espresso making skills.

Ignore anything certain people contribute to a thread they didn't originate

One thing I do know is that dogmatic dosing a certain weight is sub optimal for most espresso and Jim's idea correlates well with my preference to adjust the timer, rather than the grinder. I'm guessing the grind composition is changing with to bean age, probably coarsening due to more fracturing than shaving. As expected when coarsening, dose must increase. It may eventually turn out that as coffee ages we should both coarsen and increase the dose.

Back in the 80's a pal picked up an old Cray for 10 grand from a university. I'm hoping an SEM shows up on eBay.

cafeIKE wrote:Consider the case where the radius ratios is 1:2. The areas change is 1:4. However you need twice as many of the 1r as the 2r to fill a fixed distance, hence the total is 1/4 x 2 = 1/2, the same ratio.

It seems to me that the inherent problem with this logic is that we not filling a linear distance, we are filling an AREA. The problem is complex in 2D though, because the area of the voids and the number of circles (and voids) do not change linearly together. The problem becomes even more interesting in 3D

Ken Fox wrote:Mental Exercise:

This entire thread is an interesting mental exercise (the quoted post being a notable exception). Does it improve my espresso skillz? Maybe not directly yet, but it is certainly causing me to THINK outside of my normal box and to me that is always a positive thing.

cafeIKE wrote:Ignore anything certain people contribute to a thread they didn't originate

One thing I do know is that dogmatic dosing a certain weight is sub optimal for most espresso and Jim's idea correlates well with my preference to adjust the timer, rather than the grinder. I'm guessing the grind composition is changing with to bean age, probably coarsening due to more fracturing than shaving. As expected when coarsening, dose must increase. It may eventually turn out that as coffee ages we should both coarsen and increase the dose.

Good: Consider changing any and all parameters when making espresso from beans that have aged past their prime. Molecular explanations of why these changes work will be, at best, incomplete, and at worst, misleading. No one specific change in these parameters will work for all coffees at all points in their evolution.

Better: Adjust your coffee consumption routine to reduce the likelihood of deterioration in the coffee in the first place, reducing or eliminating the need to change these parameters very much. These adjustments include getting a "better" grinder and using fresher coffee, with the freshness coming either from more frequent coffee purchases, more frequent roasting, or judicious use of the freezer.

ken

Ken Fox wrote:Molecular explanations of why these changes work will be, at best, incomplete, and at worst, misleading.

Gosh - that seems to be a short sighted view. As one who values knowledge and learning I feel that the exercise in itself has rewards, and that the realm of possibility expands with every increace in knowledge.

To challenge theories with skepticism is healthy and useful
To discourage the pursuit of knowledge is not.

This morning trying a blend of Brazil Moreninha Formosa, Java and IMV beans I had a very nice first try where the basic flavors and temp of extraction seemed fine but it had about 20% more volume then I thought ideal. Normally I would have tightened the grind a bit but instead I added another 0.7 gm of beans to the dose. It did exactly what I wanted and it improved the espresso as I had hoped. I didn't do the other experiment to change the grind but instead got to my caffeine limit with a repeat of the successful experiment. I would not have tried it this way if not for this thread so thanks.

Otherwise, I see this discussion degenerating into an exercise in mental masturbation. I don't understand the need to divert attempts to explain coffee extraction with scientific methods.

PS- I don't believe a scanning electron microscope (SEM) is a good way to measure true size and shape of ground coffee. Samples that need to be held under vacuum and possibly surface coated as well will not represent what is there at room temperature and humidity. As described, the laser defractometer or even a simple dissecting microscope, camera and size marker spheres as controls would be better IMHO.