Thanks for your response, the point is that the roast has not changed and I was able to stay in the sweet spot of extraction over the aging period with minute adjustments of the grind. (Mind you, I always run out of beans well before they are past 2 weeks post roast)

Switching to the dark roast I did go coarser, but I am back at the good stuff and the grind is where I think it should be judgimg the flow and the result is sour. I only used the preground to see if the result using that came close to the days prior owning a super jolly and it didn't...

Marcelnl wrote:i agree with you, it is just that I seem unable to increase the temp...

I reckon screwing the pressure adjustment clockwise into the valve should up the pressure (which seems to work) but the temp remains the same at around 93-95 'C
Turning the little screw counterclockwise results in a release of pressure, so my logic should be ok but the boiler temp appears evasive of logic and the gas laws.

i am at a loss here...

I had a similar problem with my lever and Kitchen Aid/Gaggia machines and it is one of the reasons I put PID controllers on both.

Unfortunately a Faemina can not be PID't as the temperature is controlled via the boiler pressure, but anyway; 95'C should be just right for the beans I'm using and the GC gives the same sour result

You've found an interesting conundrum. I'll be curious to know what turns out to be causing the sourness.

To rule out the mano, I think you should try brewing the fresh coffee with a bottomless portafilter?

To rule out the beans, I think you should try buying fresh coffee from another roaster. Brewing espresso with stale or preground coffee usually ends up with unpalatable mess. The mess is usually underextracted as stale or preground coffee do not have enough resistance to restrict the flow of water and brew espresso. As we all know, underextracted coffee are sour. Maybe you can also try brewing the sour beans using Aeropress and with water at a relatively high temperature? People on this forum said that if the brewed coffee is also sour, then it is the beans causing the problem. I haven't try this method so take it with a few grains of salt.

The machine is probably okay as you brewed coffee on both machines and they both end up being sour.

To rule out the grinder, you probably need another grinder or rule out all other variables. We will leave this to the last.

Yeah a conundrum it is, though I'm not sure if I find it 'interesting'

Thanks Thomas, for your information.
I agree preground is ususally too coarse, but Inknow ites taste and can restrict make a okish espresso with on the GC.

Our current hypothesis is the wallpaint we put on the kitchen wall two weeks ago...it may sound crazy but it' s the only variable we've come up with that has not been tested and changed in any way. The hypthesis still stands upright at this point, water used in that machine is tap water so that can also be ruled out but e big difference is that the coffee sits in aluminium cups and the result is not sour ( if extremely weak and clearly tasting thin and like a very dark roast)

Am going to put my setup in the bathroom, get even more fresh beans AND preground coffee and bottled water and see how the results are.
Will also grind some beans in the grinder of a friend but I think that the grinder is ok as the preground stuff also results in very sour espresso.

i know Illy preground is not the best, yet I have used it for a good while and know its taste profile which is nowhere near as sour as the crap i'm currently making.
Yesterday I ground some beans a bit coarser and added hot water (97'C), the result: not as sour as espresso but still unpalatablw.

Small update: opening up two nespresso cups and making a small espresso with the ten grams of very dark roasted coffee resulted in an also extremely sour espresso, had to restrict the lever quite a bit as the grind is apparently quite coarse.
The taste 13 espresso was an extremely dark roast and tasted like it, apart from the sourness...almost burnt...yuk

bTW: no bottomless PF for faemina, dare say that distribution or tamp are not the issue...

Ps: finding a normal faemina PF is nearly impossible as it is, anyone with one lying around is welcome to contact me as I' m after a pf with the brown bakelite handle...


Next experiment:

Made coffee using a fresh can of illy preground, using hot water from the faemina> weak but not sour coffee...this makes me quite sure the water is not the issue.

Latest experiment:
My beans in a friends grinder gaggia classic, his setup water etc >sour espresso
Fresh can of Illy preground, his machine > sour espresso

Unfortunately he had no beans in house, will be continued but I am beginning to think my taste is off or I am suffering from a mindblowing case of halithosis...but then again, my GF confirms my taste results.

I am not surprised that Illy preground is sour when brewed as espresso. It is afterall preground.

Did you get your friend to taste the sour espresso that is brewed using his grinder and machine? Is it sour for him? I think the problem is the beans if the brewed coffee taste sour. Try another roaster.

In case you have bad breath, brush your tongue. It improves your taste sensitivity.

Well, the Illy preground does come in a pressurized tin which to some extent keeps the oils inside...Have been using it in the pre grinder days and it is ok-ish if not great.

The beans also were my first guess, contacted the roaster and he did some taste comparisons on a faemina he happened to have around and he did. Not find any excessive acidity (he roasted for several barista national championships over here and I have used his roasts for a while now with great results). His coffee is widely used and he is quite shure the problem is not in his roast, also because it is well used by other taste experts and coffee shops...Will go ahead and buy some more beans...this is proving an expensive challenge and an elusive one...

Marcelnl wrote:Edit: just noticed that the safety valve is leaking steam, so that probably is why I am having a hard time getting the temp higher...just managed 95 'C (Measured after flushing twice straight in a double walled glass cup without the PF) and the acidity is a bit less.

Was it the safety release valve(one on steam valve) leaking or the pressure relief valve(one opposite the steam valve)?

The safety release is a membrane, and if it is blown then you'll never get up to pressure/temp. The pressure relief is the adjustable one and according to an old Faema tech the pressure should be at .4 bar. If you don't have a manometer to attach to the steam wand they're easy to rig up. Just attach a piece of robust tubing to a 2 bar manometer, and then attach that to the wand.