Vanquishing the Pit Monster.

The following picture shows the 4 pits on the top of the puck, there is also some evidence of cracking, although it is possible this happened after the pour. In any case these are what I am trying to get rid of.

I have delayed writing about modifying the adaptor to fit the X3 until I used it for a while.

Here is the front of the adaptor. I made no real changes from the original adaptor, but I did cut a small lip into the outside edge to seat the dispersion screen. You might notice the nick out of the rear edge. The problem was that it was very difficult to hold in the lathe to machine, and it popped out of the chuck, right at the end and put a few dents in the rim. I even made up an adaptor to fit the center hole, but the hole at 4.2mm was really too small to hold the adaptor accurately enough for machining.

Here you see the back of the adaptor. This is where most work was done. I did not touch the pod void as this proved to fit the FF! X3 perfectly. It is important that the lip at the top locates into the filter screen groove. Here was the major difference, as this was about 1.5mm from seating (measured with Plasticine). The adaptor has a groove for seating the o-ring, I machined flush, and then removed an additional 1mm or so. You can just see the color difference in the picture below, at the base of the curve - thats how much came off. You can also see the outside edge where I had to machine a step to clear the upstanding lip on the X3. You'll see it's in 3 steps, because the X3 lip has a small radius.

Here is the modified adaptor fitted in place in the X3, we lose about 2mm of head room in the filter basket. The screw is a standard stainless 25mm length M4. I decided to go for a slot head as it's easier to keep clean.

OK, now for some post modification puck forensics. As you can see the pits are no more - also no sign of cracks in the puck. There is an impression of the screw head, due to expansion when brewing - but there is clearance when the grounds are dry. Anyway I believe that is a much better looking puck. I understand the idea is a dry clearance the thickness of a small coin - which I have - with a 15g dose (see below).

My dosing is pretty standard, I grind into the portafilter, use the back edge of a butter knife to level it (no pressure, my cooking teacher when I was 12 would have smacked me on the knuckles for that) and then tamp. I had a couple of baskets of my grounds weighed after leveling and in both cases it was pretty much bang on 15g, so that is only a 1g updose.

Positive comments on the modification:

1. It is now easier to clean, the pod void and o-ring were a pain.
2. It has a better looking puck, no pits or cracks and it is dry.
3. I only have to wait a couple of seconds - previously I might have had to wait 20 or more seconds to avoid the dreaded portafilter sneeze.
4. While I have no confidence in MY ability to taste the difference, I think it does.
5. There was no change to crema production.
6. It limits you to a 15g dose - which is close to design intentions anyway. One point, the Gaggia screen I used is fairly curved. I think you could get a little more headroom using a flat screen or a convex tamper.

Negative comments on the modification:

1. It is not bolt on as I had hoped.
2. The machining was fiddly and difficult. Without free access to a lathe I doubt it would be economical to do this.

Overall Comment:

A fun way to spend a morning out in the garage in the pursuit of better coffee.