Hi to everyone and I hope that this post is in the right section. I will try to keep my post short and I appreciate any help!

I am new to the world of home espresso machines and after some research I ended up purchasing a Breville Dual Boiler and Niche Zero (I have not taken delivery of the niche yet).

Currently using the Breville Dual Boiler and a Commandante C40 to try to get some decent results and running into every single shot being extremely sour. I have read the guides on here, watched hours of videos. Gone through about 1000 grams of various coffees (roast dates are around 7-10 days ago). I have ground so fine that the machine chokes, ground too coarse so extraction happens too quickly and even when I am able to get around 36 grams of espresso in around 25 seconds (18g starting dose) it is still sour. Tried everything from 17, 18, 18.5, 19, 19.5, 20 gram doses as well.

I am only using the manual button and the pre infusion (pre wetting) is as it is set from the factory. I have tried temperatures from 195 to 203. For tamping and distribution I have the jack leveller and the stock Breville tamper.

My pucks all have the shower screen impression, additionally they come out crumbly.

I am so new at this, I know this is all my fault. I just can't seem to figure out which variables and techniques to change/improve on.

What kind of beans? What water are you using? Conventional wisdom says lower the dose and grind finer, at a higher temp. Are you new to espresso? Novice palettes often confuse bitter and sour, sour and bitter. Maybe you just don't like espresso.

I am new to making Espresso at home but have been drinking it at shops for 20 plus years. I have had sour shots from shops before but never like this. I am certain I can tell sour from bitter. Additionally I use an aeropress at home and enjoy light roast all the way up to dark and have experienced various flavours coffee has to offer. I am using some beans from idrinkcoffee that were roasted feb 15 and water is distilled with third wave water (espresso blend) added.

I will try lowering the dose and grinding finer, I had not thought of going below 17 grams in the double basket.

The most important thing to aim for is an even extraction. If you don't get an even extraction it is going to to be unpleasant every time.

Your machine is set at a relatively high pressure and that is going to work against you with light to medium roasted coffee because you're going to have to grind finer to slow the flow to get enough contact time in order to not under extract. However, when you grind finer it is going to increase the likelihood of channeling which is going to cause an uneven extraction. With a 1:2 ratio (18in/36out) it is going to be challenging to balance this.

My suggestion would be to aim for a 1:2.5 or even a 1:3 ratio. Even if that is not where you want to end up eventually, it may be easier to get an even extraction this way and then you can work it down from there. I would also suggest a long pre-infusion which tends to help the coffee puck heal up and prevent channeling.

Excellent thank you very much. I just happened to try some off the shelf dark roast and I ground it really fine, did a light tamp and it was 16 grams in 32 grams out in 25 seconds. It was excellent and I used a bottomless portafilter and there was channeling but no spraying or anything crazy.

The puck didn't come out solid.

I think I am getting closer and the points you bring up make a lot of sense.

Great, a couple points:

- if it wasn't clear I meant to suggest a coarser grind with the longer ratio which will make channeling less likely..

- I would not worry too much how the puck looks after the shot. If you are using a smaller dose in a larger basket you are going to have wet pucks after the shot. That tells you nothing about whether the shot was good or bad. It's just a result of having more headroom in your portafilter. Don't read into it.

Ahhh okay thank you again, that really clears things up on the puck. One less thing to "worry" about.

As far as the coarser grind goes...I fear that until my electric grinder shows up the steps on the Commandante C40 seem to be limited to choke the machine, kind of close, too coarse. Like literally one setting seems to work with one bean! I do not have the red clix and I do love the C40 for aeropress but my espresso skills are zero so again probably me doing something wrong.

Espresso 101: How to Adjust Dose and Grind Setting by Taste

start off with a 'regular roast' but freshly roasted ( like a week ago) as most grocery store beans are a year old and will always run fast (and sour).

I have tried this. One medium and one medium dark, roasted feb 15 2022 from a Canadian company. I also tried Starbucks French, another "sweet espresso" one from a grocery store and one other brand from Costco. Oh add a light roast from a local company roasted end of Jan. The worst results are the "fresh" ones. This is definitely a me thing. Lack of experience is the issue. I am seeing somewhat promising results by varying the dose as I think the Commandante C40 is just not fine enough to dial in the fresh beans I have.

too fresh is also not great, I'm not familiar with the C40, from what I read is's use for espresso is a bit handicapped;

Comandante C40 for espresso

Did you also go BELOW 17g, as channeling gets in your way quite easily when you overdose?

Key message is to keep at it!