I’m cheap and this coffee is not, $16.99 for 12oz. This morning I made 4 shots and put 3 of them in a latte with 4oz of non-dairy milk. Better and less hassle than making a double shot and a single shot, switching portafilter strainers in between. Having the shot of straight espresso left over, I sipped. Very different. I expect straight espresso to be a bit bitter. This was sour. Sour espresso indicates under-extraction. This article on the Sip Coffee blog goes into why espresso can be sour and how to fix. It also covers the opposite problem, over-extraction, with causes bitter espresso. I will try the various fixes in the next few days and tell you what I find.