Well that was interesting reading the topic you linked to, the idea that high temperatures dont lead to 'burning' as such but the release of compounds that create a bitter flavour is something I wasnt aware of. I think at the moment I am minded to reduce my variables so as you say leave the Pstat at a setting that would be generally considered as reasonable (assuming that my gauge is correct, well not assume confirm) and then adjust grind setting, tamp pressure, preinfusion time etc as separate variables and see how that progresses.

On the grinder subject I will hopefully be pairing the Empress with an aging but handsome Italian called Fiorenzato, currently in bits after major bearing replacement surgery and unfortunately in need of an expensive 3 phase inverter to get running D'oh! I also need to get the burr carrier back onto the axle which is so tight it's not so much a friction fit as an interference fit. So I think the burr carrier will be going into the oven at some stage and the grinder into the freezer! Actually I think the freezer might not be such a good idea.

Here's some pics, I think when these 2 have finished their respective overhauls, renovations and restorations they will make a well suited pair sitting somewhere in my kitchen.

Oh and also a picture of my current grinder - the less said the better $15 from the charity shop and made by a company with a somewhat less than ethical history.

I agree my current grinder is not going to give me the consistency to dial in the empress, the fiorenzato should hopefully not take too long to get set up - a drive inverter, plastic inner for the doser and new burrs, so I hope I can get both working together, although it would be tempting to get something in the interim, I saw a nice used mazzer mini for sale on gumtree near my brothers in London.

So I finally got my finger out and ordered the parts I needed to get the Fiorenzato grinder up and running and did a raid on the bargain corner at Ikea for a bit of countertop to sit on top of some old kitchen units to put everything on (£5 for a 1.3m long piece of acrylic countertop not bad once the scratches were buffed out). I will build a nicer set up soon, but at the moment we are not sure wether we are doing a full blown extension or just renovating so its a bit of a lash up to test things out.

I will put up a separate post about the grinder as it might be useful for people who either unwittingly like me or out of choice need to run a 3 phase grinder on a domestic single phase supply supply. I ended up ordering a 0.75kw inverter drive - 1 phase in 3 phases out at 240v +- 15%. I was a bit nervous as it was quite an expensive way to test wether I was right that the grinder was 3 phase! I initially tested it with a jumper across the drive enable switch terminals and used the built in keypad to test the grinder, the presets for the drive ramp it up from 0Hz to 50Hz in 5 seconds on run and the same in reverse on stop this is nice and gentle but does mean there is very little torque as it builds up to speed which can lead to stalling if there are fragments of beans in the burrs, so I may need to reduce the ramp up time and also look at the setting for boosting the current at low frequencies to provide more initial starting torque. The thing I was really pleased about is that I was able to run a control cable to the original power switch on the grinder from the 12v control terminals on the drive, by then locking out the keypad using the menu the drive can be started and stopped by the grinder switch.

I have noticed straight away an improvement in consistency of grind (still using the old burrs - new ones arriving today hopefully) and this and the use of a proper tamper (not the bottom of a glass!) has had an impact on the extraction time and quality of the shots I have been getting. I'm still obviously a long way from where I want to be and really am still just tinkering, my goal is to have a point where the machine is completely assembled and in place the grinder is working as I want it and then I can focus completely on learning how to get the results I am looking for.

As you can see from the pictures, coffee grinds end up pretty much everywhere in the doser other than where they are needed, so I may experiment with a turning vane to direct the grinds downward. The burrs run evenly and level, but I need to check the seating of the burr carrier as I think it is sat on top of the pin in the drive shaft not over it - it was a hell of a job to get it back on it is such a tight fit, so that is a bit of a pain. I also need to seal the acrylic tube liner for the doser at the top and bottom I used 110mm OD tube which is a bit loose as the next size up is 120mm which is too big to fit I might order some 120mm and take a slice out of it to allow it to flex in a little. I also need a nice lid for the doser at the moment I am using the lid from the cardboard postal tube the acrylic came in, nice snug fit though.

Any way onward and upward!

Nice grinder ! You could have it perfectly running with only 5$ capacitor.