Clump by definition indicates lump of something. Lump of something among ground coffee bean should be a lump of coffee bean grinds. Usually, this lump indicates grinds in close proximity of each other, therefore, this lump should be denser than the loose grinds around it. How else would you explain it?

Clumps are ephemeral like clouds or fog.

The slightest disturbance - poof - they're gone.

I've tried to simplify my process by grinding directly in the basket instead of into a catch cup + WDT but I always end up with areas of extremely uneven density when trying to distribute, and I also realised the time it takes for me to distribute by hand is basically the same time as stirring with clump liberating wdt so, eh.

I don't know about objective scientific studies but I measured a few data points of time to get a certain weight out (flow rate?).

My hypothesis going in was that WDT at the same grind size will slow the flow as it is more evenly distributed which decreases channeling. I had noticed this with my home roast when I first started WDT; I had to go a few steps coarser on the grinder to get the flow I wanted. My home roast was medium Ethiopian.

So I took my DF64, Strega, and some Lavazza Super Crema and did some measurements of different prep techniques. See below:

18g in of Lavazza Super Crema. Measured time to 30 g out:
Normal workflow: Grind to dose cup, transfer to portafilter and then WDT. One or two tamps to settle
36s
Grind to dose cup and dump in portafilter. Single tap to settle.
50s
Grind directly to portafilter. A little finger leveling and tamp
47s
Repeat normal workflow at top
32s

Results? Different than what I had previously perceived. Subjectively the coffee seemed like it flowed to one side in the non-WDT attempts. They all tasted like Super Crema. Objectively the coffee ran faster in the WDT routine.

Take it or leave it...

You are making an assumption that a tiny difference in density pre puck compression effects density post puck compression. Do you have any actual data that this assumption is true? So if we are giving our subjective view of physics, it is simple physics that a difference in pre puck compression which is orders of magnitude less that the density of post puck compression will have no effect. So my question remains, is there any data to support you assumption or mine?

bullet08 wrote:Clump by definition indicates lump of something. Lump of something among ground coffee bean should be a lump of coffee bean grinds. Usually, this lump indicates grinds in close proximity of each other, therefore, this lump should be denser than the loose grinds around it. How else would you explain it?

Until you flatten the whole thing with your bodyweight on a tamper.

TheodoricOfPuck wrote:So my question remains, is there any data to support you assumption or mine?

No.

espressotime wrote:Until you flatten the whole thing with your bodyweight on a tamper.

I would call that a "puck". I noticed the other day tapping the coffee grind in the basket against tamping mat created a crack down the middle of settled grinds before WDT. Wonder of WDT and distributor got rid of it before tamping. Shot came out fine.