ForzaItalia1 wrote:Grazie Mario! Forza Napoli!

I will try to measure out 7 grams per shot going forward.

I guess I am still confused as to why the flow starts off perfect but then goes too quickly. Is the water pressure increasing after I start? I would think the pressure should stay consistent. Just hoping this is not an issue with my machine.

If you really must use those beans, try to updose them. In a single basket I'd try to go around 9-10g, and a double I'd plan to get around 18g or so if you can. Unless you are hitting the shower screen and causing channeling, you'll likely need all the coffee in the basket you can get to keep the pressure up throughout the shot.

Sometimes I run out of coffee from my home roasts and don't have time to roast another batch, I've tried how to pull un-fresh coffee, and really it almost never works. Better off to just make it with pour-over or an Aeropress. Even just roasting 40g of green beans in a cast-iron skillet comes out so much better as espresso in a pinch.

ForzaItalia1 wrote:Hello,

Newbie here. I just purchased a used Nuova Simonelli Oscar with a San Marco grinder. I am having a tough time making the perfect shot and already wasted 1 kilo of lavazza super creme beans!

I think i finally got the perfect grind level....the shot starts flowing at 5 seconds at a good rate but then it starts flowing way too fast and comes out watery.

Anyone know what may be the issue here?


Thanks!
Italia

The answer to your question is very simple and it has nothing to do with all the advice you received above.

The Oscar does not have an OPV like other machines, which means that the extraction presure starts @ 9 bar and then rise to 13 bar and that why you have channeling.

You need to install an OPV - look on YouTube for a clip that deal with it and buy a set of it.

You don't really need to install an opv if your beans/grind are good. I installed one on my Oscar and then eventually realized it was unnecessary. It's sort of a circular reasoning thing. If your opv kicks in then it means your beans/grind are off. The puck should regulate the flow correctly.