Hello fellow HBers, I recently acquired a NS oscar, for the first month or two I was making some awesome espresso my technique is:

- Flush a cup full of water at the beginning of a session
- Grind beans evenly in the portafilter
- Tap the side of the portafilter several times with my palm to shake the grounds around
- Tap the portafilter on the counter to settle the grounds
- Tamp straight down ~30 lbs of pressure
- Do one quick flush
- Brew for 20-30 seconds.

Within the past week I've been getting bleh results, I can pick up on this salty/bitter taste in every coffee I use. It also manifests itself in lattes and capps, not just straight shots. I haven't changed anything in my technique.. I pulled out a bottomless PF and pulled a shot with that for the first 20 seconds of the shot the pour looks super even then the pump changes noises and it starts to spurt. I should note, I don't get very clumpy coffee and trying to stir the grinds yields the same result.

So far this has happened with 2 coffees:

Big Trouble from CCC
Heart mender from Commonplace

I typically put 18 grams in and get 30-32 grams out, this has always made an excellent latte. I should also note, the spurts only began happening recently I don't remember getting them at first, and If I did it didn't affect flavor significantly.

I wonder.. could this be a temp issue, or maybe the machine has significant scale build up?

Descaled /we'll see what happens in the morning!

LukeFlynn wrote: - Flush a cup full of water at the beginning of a session
- Grind beans evenly in the portafilter
- Tap the side of the portafilter several times with my palm to shake the grounds around
- Tap the portafilter on the counter to settle the grounds
- Do one quick flush
- Brew for 20-30 seconds.

You're not tamping at all?

It's hard to believe that you've accumulated major scaling in a "month or two" unless your water's really bad or your guesstimate's really off.

Forgot to add tamping. Tamp with 30 or so pounds of pressure, nothing too fancy or crazy.

My water is fairly hard, I neglected to mention I purchased the machine used.. It's a 2008 model, and it never appeared to be descaled.. I'm sure there is something living in there. When I get the chance, I'll disassemble the machine and do a full on proper descale. I'm sure there is more judging by what came out!

Also, I went ahead and pulled the screen off. It appears that even though I backflush every day there was a bunch of coffee residue on the rear of the screen. I will say this; the taste is marginally better this morning, I no longer get a salty aftertaste.

Confirmed after pulling a bottomless pull - I no longer get channeling. I wonder if the coffee residue/buildup on the screen caused a variation in pump pressure. The pump would often change noise as if it was increasing the pressure; By the second change of noise the espresso would turn into a gusher. Now I don't get any weird pump noises, it's fairly quiet too has a similar noise level to a rotary. Now I know the importance of backlashing... not something to neglect. (Or descaling.)

So, I realized something.. everything I did was unnecessary, I was blaming myself and my equipment. I realized this had only been happening since Saturday, then it clicked.. I got a cold on Friday and woke up feeling awful on Saturday (Stuffy nose, sore throat, etc.) then I finally went *duh* taste relies on smell... especially considering anyone else I made a drink for never complained or reported a "bitter/salty taste". I remember reading a post about someone drinking espresso while they were sick describing similar symptoms.. I feel dumb, but at least I know it wasn't my fault! Has anyone else had this happen to them?

I have no experience of what a cold does but can imagine it may cause your taste to go off, yet I can vouch for the effect of quittting smoking...the result was a strange metallic (could also call it salty) and sour tasting espresso which faded over several weeks, returnin to normal after a good while.

Ahh, that's a great description of the taste I am getting - metallic.