I am having a problem which started suddenly about 5 days ago, with my LMLM, and which I have been unable to solve. I had bought a Sproline group screen, and the first shots out of it were the best-tasting shots I ever pulled. I was able to keep my grinding and machine parameters about there they had been for the IMS screen I had previously been using. I should say near the outset that I have had minimal problems with the LMLM, and very good consistency, as one would expect.

Then suddenly my shots started tasting quite bitter. Since my equipment and workflow otherwise than the new screen had not changed, I dialed things in again, did a chemical backflush although it was not scheduled for a few days, redialed and cleaned my HG One grinder, but there was no change in the taste of my shots. I then went to my roaster, whom I know quite well, and asked her if she would check the roasting profile of that batch, and she did, saying that someone other than her had roasted it, that the first crack had been at 12 minutes rather than the usual 10 minutes, and she gave me some newer beans that she had roasted and cupped herself. Things with the new beans were slightly improved, but to my taste not significantly so.

So I put the IMS screen back in, redialed in the beans, and again got some improvement, but very modest. I simply do not seem to get much of the aromatics (for lack of a better term) out of what I am pulling. The pull looks normal, the crema amount is what one would expect, but the shot is still lacking depth and complexity.

I use an 18g VST basket that I have used successfully for over a year, weigh the beans, use WDT and a light Stockfleths, use an Eazytamp - nothing had changed. My water is the same, and tastes fine as well. The pressures on the LMLM - via the gauge anyway -- are unchanged from what they were. The temp on the PID analogue dial has remained at about 202°, where it as been for this roast - I did try upping and lowering it a bit with little change.

I am about to try another roast which I have, a lighter one, to see if I can dial that one in better, but those beans are a bit old. What puzzles me most is that fact that what has happened seems an abrupt change, and such a difference has mostly seemed to occur in the past for me with inadequate coffee (too old usually), a dirty machine, or poor distribution technique. I lack a scale to weigh the pour, a Scace (although I can borrow one), or a refractometer.

Any suggestions?

Switch to a different roast, and enjoy. Try not it obsess about changes as you have no control over. (And even when you think they are, they often they aren't!)

Not only do roasts change from time to time due to various factors, but so does a person's palate. You are human, you are dynamic. Our minds do all sorts of wonderful things to adapt, filter information, and influence our perceptions.. Taste or otherwise (look up the 'McGurk effect' to have your mind blown). But not only that, there's also physiological changes associated with diet and disease, that affects our senses.

Anyway I'm rambling.

If it helps, this happens to me all the time. The longer I stick with the same roast, the less enjoyable it is. I've learned now to adapt by alternating through many different roasts. Almost EVERY time I try a roast I haven't tried in days, weeks, or even months, I enjoy it as I remembered it, sometimes even better.

+1

I had a sinus infection early this year, I couldn't drink any espresso.

Both of the suggestions I have received -- about enjoying a switch to another roast, and having possibly a virus are certainly reasonable. I will say that my wife and son, both experienced espresso drinkers and one (my son) with some time with his own home machine, agreed with my dissatisfaction, more or less.

One thing I did not mention is that the just-ground coffee out of my HG One started feeling different when leveling about the time I noted the change in taste; it felt like it was packing differently, almost like it was slightly damp. I just attempted to look at the grind with a 50X hand 'scope. I am no expert here at all, but there were all sorts of different sizes of particles and nothing as uniform as I had imagined. I will be happy to disassemble the HG One, check the condition of the blurs (3 months old), lubricate the device, and reassemble, if someone thinks this could possibly be significant.

Was there anything that could have affected the alignment of your HG-1? Bad alignment definitely adversely affects taste, but it would also tend to have other discernible effects such as channeling or changed extraction times.

I do wonder about the HG One, but no there was no specific incident or observation that would indicate a misalignment. Tomorrow when I get time after Christmas, I will look more carefully into the HG One's condition.

Since you indicated your son had an espresso set up, easiest confirmation would be to ask him to bring over his grinder.

You may have a slight buildup on the burrs of your HG1 that's throwing things off.

This morning checked (for alignment and any defects I might see in the burrs themselves), as well as cleaned and lubricated my HG One. Shortly I will report on whether this has made a difference.