I bought a couple times from this guy, best price, fast and free shipping within the US.
10lbs. Brazil Yellow Bourbon Green Coffee Beans, They are Raw, Unroasted. | eBay
Some mentioned Starbucks and Tim Hortons, you guys need to get out and try some GOOD coffee.
That's like when people say Millers and Bud is a good beer lol:)
Totally agree with it depends where you are, find some good coffee shops/bars and try their espresso.
If you like it ask what kind of...
Sounds like you are getting too much pressure, there is a way to adjust but it needs a tech to do the job.
Try to do a search online to see if anyone else had the same problem and you may find the solution.
Sounds good but will it open a beer bottle and scratch your back the same time? :)
As a project you will have your hands full, keep us posted and good luck.
Robusta is really good to a certain amount in your espresso blend.
In Italy most cafes mixed it in their espresso.
But you have to experiment how much you like.