I had an interesting experience. I was using a spirograph WDT device, but not on a perfectly level surface. Well, the grounds were not level to the basket. Even though I tamped with a leveling tamper, the shots were still noticeably one-sided. Moral of the story: grounds distribution >> tamping

Same The beautiful tamper I bought on Etsy sits on my accessories shelf just for decoration. The PV has a small diameter

That's possible. Old roasts tend to have less crema than fresh roast. The expiration date shown may not be faithfully chosen. Any roast older than 1 - 1.5 month is... "over the hill", "past its prime". That's why I do my own roasting so that I know what the real expiration

Air bubbles coming out the anit-vac valve and all your other symptoms point to a not-sealing anti-vac. Could be what cmin has experienced and the o-ring has failed. But before you resort to disassembly, (even though it is super easy), give it a tap with something hard like a small hammer... a tap, not a smash, or several taps, in

Boiler water/steam is either leaking through the brew valve (which you might see as movement in the tube moving toward the center of the boiler) or past the pipe in the boiler (which you might see as movement moving away from the center of the boiler or perhaps just escaping out through the group). You could remove/inspect/clean and reinstall

It's a dual boiler machine. It's going to heat an empty brew boiler and destroy its element if you do something like that. The pop was probably the element rupturing and the smoke was probably from what-all got burnt. I agree with Dave C's "Open it and see how bad it is" opinion

One of the roasters exhibiting at the London Coffee Festival earlier this month was using a Swan. He was very unhappy with the shape of the hopper, saying that he had to keep toying with the beans to get them to drop properly into the grinder

Do you have a compilation of that work anywhere? I'm interested in your procedure and what you define as retention. I've always taken retention to be the ground coffee that causes shot to shot dose variation, which is pretty easy to measure in single dose grinders. I've always figured that stray coffee that got packed off into

Monitor & photograph your results for reference as colour is an indicator of scale present and your progress

If the boilers aren't filled with water, and you send electricity to the heating elements, things will go pop?