This kind of "puckology" is seldom revealing of channeling, at least on better machines. There is a huge rush of water out of the basket when the three-way valve opens. Many times the defects seen are due to that rather than something ...

... mid shot. If it is clearly extracting more on one side and bald in places I find it isn't nearly as good. Others will say this is sort of like "puckology" I.e. worthless, but I find it to be very indicative of the

A few considerations you might want to ponder on: - The grouphead and machine you have are fairly notorious for having a huge temperature "delta" between what you measure from the grouphead surface to what is actually the brew temperature. From what I recall you might want to have the grouphead temp...

I've seen that video before, but in the first two shots the puck compressing and expanding again don't seem to change its shape much, in the sense that the taller parts of the compressed puck are still the taller parts in the expanded puck. Here are the side-by-sides. {image} {image} Overall the sha...

Search for puckology. It's something of the past and has been shown to be pretty useless a long time ago. Just as Nunas already showed every machine with a 3-way valve will "destroy" the puck after the pressure is released. For ...

When one pulls a shot, the puck first expands as water permeates the grounds. As pressure mounts, it is my understanding that the puck is greatly compressed by the pressure of the water. Then, when the pull is over, on machines with a 3-way valve or e61 (maybe others), the pressure is suddenly relie...

Search this site on ""puckology"" and you'll find lots of discussions of post-extraction pucks. Pre-extraction pucks, as you pictured in your post, is a relatively untreated topic. But assuming good distribution, I'm deeply skeptical ...

Look up puckology. Short answer it's completely useless to look at your puck and try to derive any conclusion fomr it about extraction. Only way to do this is using a naked portafilter

Search on ""puckology"" to read other prior discussions. FWIW, I agree with the other posters that (a) it looks like a dispersion screen impression, (b) looking for evidence of channeling with a bottomless portafilter offers more ...

Are you single dosing? Are you purging old grind leftovers from the previous shot? 5-6 seconds is normal to start for a well flowing shot. Dose, grind, taste and shot volume are all interrelated and must be adjusted in concert. I concur with going to 17.5g - depending on the coffee - and grinding fi...