In our minds the best espresso machine is one that can make great tasting espresso (and probably steam some milk add to it) and is simple to use. That way you'll never shy away from using it out of laziness (it's understandable, we can all be a bit low energy in the morning), and you'll never be tempted to go to the coffee shop instead because their offerings taste so much better. Accordingly we focused our testing on how well each each machine could satisfy our taste buds, and how easy they were to use and clean.
To evaluate taste we recruited the most diverse set of palettes we could. We wanted to make sure we got opinions ranging from people who aren't particularly fussy about their coffee, to people who could really pick apart the nuances of each shot. After an intense round of recruitment our talented taste testing team included a few casual coffee drinkers, a few people who already own their own espresso machine, a professional coffee roaster, and a former professional barista.
For the actual taste testing we first had everyone sample some straight espresso from each machine. We used the same coffee beans across all machines, except for those that took their own dedicated capsules. We made sure each shot was freshly poured, so that each shot was at it optimal taste level and our results weren't skewed by shots sitting around and stagnating. We then repeated this process but used each machine's milk prepping capabilities to make a cappuccino for each tester to taste. For the two machines that didn't have any sort of built in milk frothing/steaming capability we used both an Epica Automatic Electric Milk Frother and an Nespresso Aeroccino Plus Milk Frother. After all of this the testers ranked and scored the qualities of each machine's various espresso offerings. After this we had to take all of our testers out to happy hour, to even out their caffeine high.
Ease of Use
During the time that our testing lab was transformed into Cafe testin' tech all of our testers made literally hundreds of shots of espresso. Thus we gained a very intuitive feel of how easy or difficult each one of our machines was to use. Throughout the process we took careful notes on the initial setup of each machine, the design of the interface, and how easy it was to remove and refill the watertank. Finally, we performed a cappuccino time trial for each machine, with the clock starting when we began making the drink and the clock stopping when the drink was ready and all parts that required immediate cleaning had been attended to. This gave us a definitive measure of which machines would be faster to use on a day to day basis, for those who tend to be rushing out the door every morning.
Ease of Cleaning
As we said before, Cafe testin' tech was a bustling place, so we had plenty of opportunity (and need) to clean all of our machines. We split our ease of cleaning evaluation into three categories: daily cleaning, weekly cleaning, and descaling (essentially long term cleaning). Our daily cleaning testing focused on the things that needed to be cleaned after making each drink, namely milk wands and frothers. Weekly cleaning testing looked at how easy it was to empty the drip tray, which ended up be quite simple on all the machines. Descaling, a process that must be completed every few months in order to remove any mineral buildup, was performed by our testers on each of the machines. We took careful notes on how this process differed between machines and how annoying it was (because lets face it, the best any required cleaning can be is not terribly annoying).
Our milk steaming/frothing test aimed to which machines could produce cafe quality milk, for those looking to make latte art or that care more about milk texture than espresso taste. We made both steamed and frothed milk on each machine, and compared them both visually (looking for the right sized bubbles) and through side-by-side taste testing. The milks with the best taste, texture, and foam composition scored higher.