I AM NOT TRYING TO SPOIL ANY FUN YOU WILL HAVE, BUT ...
it all depends on your level of ambition.
mmm wrote:Will I be able to survive without Eric's thermometer for a while?
mmm wrote:I've also been reading up on how to do a cooling flush today; it doesn't seem too hard.
It does not sound too hard, but depends on your own awareness of the variables in the equation, your patience and ability to patiently stick to some formula.
I have a similar HX machine (QM Andreja Premium) and did without the thermometer in the group, but developing a feeling without instrument feedback is a slow process. To get Olympic precision, the gymnasts must rehearse an exercise 10,000 times before they get at the precision desired.
Since you are probably starting a learning process where you develop your ability to discern coffees/shots you prefer over ones you like less, in the beginning you may be less discerning and feel less in need of instruments (thermometer, timer).
You can probably speed up the learning process by just buying half a dozen pounds of the same coffee and start exploring the optimization space. Too cold, warmer, too hot. Change pressure. Change grind. Change dose (with headroom and grinder setting!) Visually judge, smell, take a small sip, let it sit to record crema persistence, and do the next one. Play with back-to-back series versus ones that are spaced well in time and see what the optimum distance in time is.
So, as you are on the quest for the holy coffee shot in a multidimensional search space, you want to have control over as many variables as possible.
Some coffee roasts are more "forgiving" than others: select one coffee that will serve you for a long time, stick to it. You even want to develop an idea of how to adjust the grinder during the aging of the beans in the hopper (I now find a very small daily coarser adjustment is required). Develop a notion of how fresh the coffee is initially. Very fresh, the coffee has more gases and the trickle is fluffier (thicker), so you do not want to tighten the grinder until you get the extreme "mouse tail". Search for the grind/temperature that gives the best "tiger skin" (with darker reddish spots on the tan crema surface).
If you are thinking now I am rather finicky in taste and may have been a bit sloppy in process - you might have a point.
You may feel you can cover up some faults with the milk, but will discover in time that you have become discerning here as well.
mmm wrote:Right now for accessories to buy I have: frothing pitcher, frothing thermometer, Bumper tamper, knockbox...
Frothing thermometer - not sure you need that, but consider a digital cooking thermometer that can measure the temperature of water/coffee in the PF spout. As I don't do milk drinks, somebody might learn me the large dial classic thermometer is better, though. And, yes, I am aware the frothing thermometer can measure temperature in the PF spout as well - I just doubt its repeatability and preciseness required there.
The Motta aluminium 58 is a bit cheaper than the Bumper, and, I would consider the Bumper tamper stand/base - one of the best add-ons I bought.
If you want to take another variable out, consider the ESPRO tamper - it helps you tamp at the same pressure each time, yet more expensive.
Knock box - make sure it is dishwasher proof. I prefer that, and volume, over looks, but I put the knock box in the drawer of the trolley my espresso machine is on.
A coffee scoop is probably with the machine, but if not, a dosing spoon (the volume of about 7 grams of coffee beans) really helps.
Think shot glass so you can see what is happening during the shot.
Think digital scales, as these are more precise than the 7 grams scoop (I bought a very cheap kitchen model with 0.1 gram repeatability, however 1 gram readout - when you add one bean and the scale moves to, say, 14 gram, you actually went over the 13.45~13.55 gram threshold. I start with two scoops and updose with a few beans at a time). Remember there is a debate as to the relevance of weight over volume, or v.v.
Have fun with good coffee. Less good shots will generally be better than the best ones you have away from home, except for a few professional serious espresso outlets. And, as you become more experienced, after some time you may think it is actually more difficult than you thought in the beginning.
Maybe Chris Coffee would be prepared, BTW, to unpack your machine, test it, and adjust pump and boiler pressure to their commercial optimum. I found my machine out of the factory was set at too high a pump pressure and the boiler was slightly too hot (=pressure). To me, today, that would be an essential part of my negotiations over price. And stick to those machine settings for a long time.
regards
Peter