There is a shot timing anomaly I have noticed and wonder if any of you have found the same thing.

When a shot is timed, the timer starts (i.e. 0 time) when the pump button is pushed. The first drops of nectar are supposed to occur about 6-8" after 0. OK, my shots nearly ALWAYS start to fall 6-8" after the pump is started. However, I have noticed on more than one occasion that the shots that start on the short side (6") pull longer and the ones that start on the long side (8") pull faster. In other words, if the shot starts to fall at 6", it may take 30-35" to get a full 2 oz. where if the shot starts at 8", 2 oz. is reached much sooner...sometimes less than 22".

This seems to be counter-intuitive.

What gives?

Len

Are you getting a steady flow, irrespective of when your first sign of a stream shows?

Yes. The flow is steady.

Len

Espresso puzzlers are always fun.

My completely unscientific observation is that excessive grounds manipulation (e.g., stirring a la the WDT, mid-tamping, or aggressive Stockfleths Move) can produce pours that bead more quickly but then slow way, way down (due to fines migration?). Maybe that explains the difference you're seeing.

I've noticed the same on my setup and was also wondering why. Dans answer seems to be on target as it applies to my experiences.

An alternative way this happen is dosing variation. At higher doses, the first drops appear quickly, at lower doses they appear slowly. However, if you grind the lower dose shot for the same initial flow rate as the higher dose shot, puck breakdown and gushing happen earlier, and the shot ends more quickly.

Compressing the grinds with various grooming moves can inadvertently create an up-dosed shot. That means Dan's cause and my cause may turn out to be one and the same.

Jim,

You state:

At higher doses, the first drops appear quickly, at lower doses they appear slowly.

This too seems to be counter-intuitive. Higher dose, i.e. more coffee in the basket would, one would think, produce the first drops of coffee less quickly and visa-versa...just as it produces the desired volume less quickly and vica-versa. What am I not understanding.

BTW, I do not over manipulate the grounds (at least I think not). I do a (kinda') Stockfleths move and usually scrape the excess grounds off the top after leaving a small "hump" in the basket. I do no mid tamp and NEVER tap the side of the PF as I have found that tapping causes chanelling.

Len

It seems counterintuitive, but it's true. There's less head space, less puck expansion and coarser grind on a higher dose shot. A low dose shot that has the same overall timing as a high dose shot will always have a longer dwell time, and a faster finish.

Jim,

I understand what you say about less head space & less puck expansion but don't understand your assertion that there is a coarser grind on a higher dose shot. Why so?

Len

To get the same flow rate through the puck, either less coffee ground finer or more coffee ground coarser. This part is obvious. The part that gets tricky is to what extent the finer grind slows the flow due to more fines or smaller coarse particles.