I used the dissecting needle to stir the coffee in the filter as John suggested prior to tamp and noticed that the shot volumes in my Solis SL70 went from 3.5 oz. to 2 ounces. Am wondering if this "coffee stirring method" makes for a more compact puck, thus decreasing water flow. Anyone else notice this difference? thanks Lou

If performed perfectly, the WDT can indeed lead to what you might call lower shot volumes. I'm assuming you mean lower shot volumes in the same shot time?

Think about it this way: the point of the WDT is to improve distribution, right?

What happens when distribution is poor? Well, the water will find a flaw in the puck density and exploit it, and run faster through that flaw.

So then what if the distribution is better? There will be no (or less of a) low-density flaw for the water to run through, restricting the flow through the entire puck in a more even way.

So in the same amount of time, poor distribution on a semi-automatic machine like the SL70 can and will lead to a higher volume of resulting extraction. The problem is, the extraction has a significant amount of over-extracted volume.

I'd guess that your WDT-shot is also thicker in viscocity, and perhaps darker in color (at least the crema).

ldilts wrote:I used the dissecting needle to stir the coffee in the filter as John suggested prior to tamp and noticed that the shot volumes in my Solis SL70 went from 3.5 oz. to 2 ounces. Am wondering if this "coffee stirring method" makes for a more compact puck, thus decreasing water flow. Anyone else notice this difference? thanks Lou

That's an indication you probably had some channeling before. And a 2 oz. double shot is just about right!

Jack