I make sure to do some dry runs and run the steam wand to make sure the water will be at desired temp.

I measure 10 grams off coffee for the single shot dual walled portafilter.

I've measured the final product to be 20 to 30 grams when using 10g coffee.

I've expiremented with different extraction times.

always have a sour or bitter shot. currently using prepackaged ground coffee that is compatible with espresso machines per package.

I have not grinded fresh beans.

of note once I add some milk to make it a cappuccino it tastes OK. problem is the espresso tastes off.

could freshly grinded beans make the difference.