We've said it before, but we'll say it again:

With the Bacchi we recommend you start off by going and buying yourself a tin of roast & ground Illy espresso blend coffee from your local grocer or supermarket.  If nothing else you can have a chuckle on the way around the aisles at the best before date that stretches off some 12 months beyond the canning date (let alone the roast date!).

Yes, you read that correctly.  Start with an unopened can of Illy coffee as it 'dies' pretty quick after opening

Illy is very forgiving of poor technique in the Bacchi for some reason.  This will build your confidence in the Bacchi's ability to knock out a good espresso without the risk of you getting lost in the woods of getting your gourmet coffee grind & tamp 'just right'.

Start with a moderate, middle of the road 7g per shot (14g double) dosing and all that.  Beginners & extreme measures are seldom a good mix in our experience, not just in the realm of coffee.  A moderate approach greatly improves the likelihood of you getting very good espresso within the first couple of shots.  Its very easy to lose the plot when you change all the variables at once.  We understand the Bacchi was actually developed in fairly close liaison with Illy, although scant mention is being made of it in the marketing material.

We're not hesitant in advocating Illy if it helps you achieve a good result with the Bacchi 'out of the box'.  One of our missions is to bring great coffee within your reach at home, not to add more bull to the tide of misinformation that seems to go hand in hand with coffee.

One of the primary reasons we decided to stock the Bacchi is it is unique in that you can make an 'acceptable' cup of espresso using a tin of pre-ground Illy.  That is to say, you can make an espresso of very high quality at home without a grinder.  Our definition of 'acceptable' in this context is that it will be at least as good as the Illy espresso you would receive in a cafe that uses Illy coffee, and often far superior.

I am not able to explain why Illy is so fault-tolerant in the Bacchi, and have neither the time nor inclination to find out, the important point is that it is.

Yes, freshly ground gourmet coffee will ultimately give you a much better result in the Bacchi, but it is much less forgiving than the pre-ground Illy in our experience.  On balance starting with gourmet coffee in the Bacchi is likely to make your learning curve steeper, longer, and more volatile.

Finally, follow the instructions in the manual and discard the first couple of espresso as an amount of cutting fluid residue and metal swarf from the manufacturing process will flush out.  It does not present a threat to your health, but it wont improve the taste of the espresso.  Run a couple of cycles with just water and no coffee then you can see when the debris has been completely flushed out of the internals (using an espresso cup with a brilliant white interior will allow even the smallest specks to be seen).  We will have performed one test cycle at our factory if you buy your Bacchi from Londinium, but we will still recommend another couple of cycles before you consume the output.