Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Sour Espresso shots from beginning to end.

I'm an espresso drinker looking for a machine to brew a good tasting espresso. I started with a DeLonghiEC155 entry level espresso machine, with poor results. Then I bought the Gaggia Classic. All the shotswere sour. I tried everything recommended by several people on the Gaggia forum. Temperature surfing,better beans, roasting my own beans, adjusting the boiler pressure, darker roasts. Since I couldn't drink the espresso, I did start making cappuccinos, which this machine can do.Putting lots of sugar in the drink offsets the sour coffee taste. Not what I wanted, so I returned the machine. (Kudos to Amazon for their liberal return policy!) Wondering what to buy next to get that heavenly shot of espresso in the morning?