walt_in_hawaii wrote:you need to develop consistency; are you using a cold machine that is warming UP? or a hot machine that you need to cool DOWN? The flushing is to control your group temp. But it depends on how long your machine is on and when your last shot was pulled. Like the majority of people here, I don't leave my machine on all day. That's for coffee shops. I only turn it on for about an hour in the morning, to draw the morning's cups. Then its off all day.... From startup you can get an ok cup in as little as 15 min, but I usually wait around 30-45 min for a better cup. If your machine has been on longer than that, that's normally when you start looking to flushes to bring the temp down a little.

I use a homeplug in order to turn on the machine one hour before I wake up in the morning and one hour before I go back home in the afternoon. I make just two shots per day. For the rest of the day the machine is off.

That is a good amount of time, and an excellent routine
BUT... at this point with a brand new machine, I wouldn't do that. It does give you a very consistent warmed up starting point, but it doesn't tell you little things about the temp that you need to learn. For instance, you won't be able to tell if you should be using more heat or less heat because you never encounter the colder machine. When my machine was new, I just used a large O ring around the group head, to hold a K type thermocouple (they are very cheap now) on the head to read out temp and I would note its temp before pulling any shot, then keep track of what temp gives you the pulls you like. You can also get one of those tape strips that change color to indicate temp. That will give you a good baseline so you know what temp you prefer; then set your timer to give you about that temp for your morning and afternoon cups, and also the thermocouple or strip can visually show you where you are as you use the flush to change the group head temp. But you won't know what temp you are trying to GET TO if you don't start with the cold machine.
Although, in your case it sounds like you are doing something else wrong, because if you are already starting with a 1 hour preheat, you should be drawing a reasonable cup; if you arent happy with that, then there is something else you need to bump in your routine first, the temp thing is more for fine tuning and you aren't on the board yet.

Thank you for your advice.
I am sure that something basic is missing on my routine, except from the fact that I donnot have the time to make many shots during the same day in order to understand what I am doing.
So I am doing all the basics these days, starting from less grams (I always used 20 grams with the machine that I had before), stopped measuring the time and try to have a consistent routine until I will get more o less stable results. When I will achieve this I will try to change one simple thing every time until I will find the flavors that are best for me. I hope that if I will follow this path I will achieve some nice shots at the end.

You routine is what about breaking clumps ? try to have best distribution possible ?
Never tap with the tamper you pf !

I use a distribution tool, sometimes I use the Weiss distribution technique, never tap the tamper and the last couple of days I tamp lightly

if a picture is worth a thousand words, then a video is worth like a bazillion.
I'd shoot a quick vid of your prep routine and then the pull. I think you'd get a lot of helpful tips after everyone can see what you are doing... there's been a lot of back and forth and you seem to know enough to be making good progress, but if you aren't happy with the pull, I think others will have to look at it to get further. Just a suggestion... There's just a few of us, like maybe Samuel Law, who really just want to see your machine

Ok, I like the idea...tomorrow afternoon I will upload a video...

I have uploaded two videos.
My routine is more o less waht you see in the video.
I use a light tamping, 18 gramms of freshly roasted beans and take 36 gramms of espresso (the distribution tool is normally clean..!)

sorry, I cannot see either video. Your link takes me to youtube, but it says video is unavailable...

I am sorry, now it's ok..