We recommend models which score 70% or more overall, so long as they also score well on other crucial factors including taste and milk frothing.

The CHOICE Expert Rating is made up of taste (60%), ease of use (20%), milk frothing ability (15%), and coffee temperature consistency over consecutive cups (5%).

Three experts test the espressos in a 'blind' tasting, checking the colour and thickness of the crema (the tan-coloured foam on the top of an espresso), aroma, flavour, mouth-feel (for example, creaminess or wateriness) and aftertaste.

How easy the machines are to use. We try the controls, fill the water tank and the bean hopper, adjust the grinder, make a coffee, and clean inside and out.

We experiment with each machine to find how it best froths milk, looking for fine, pourable froth. We use what the manufacturer recommends (a milk frother, milk-based capsule or coffee capsule extracted over milk).

We measure the consistency of four consecutive coffees for each machine after it warms up.

Not scored, but will affect how quickly you can turn out a cup of coffee.

The manufacturer's recommended retail price. Prices are often flexible, so shop around both online and in bricks-and-mortar stores for options.

The recommended capsule (pod) type for each model. Nespresso (original) refers to the older-style capsules, while Nespresso Vertuo is the newer patented and barcoded system which comes in different sizes (these are incompatible with third-party capsules).

Thermoblock heats up only a very small quantity of water on demand as it flows through the system. Boilers heat a larger amount of water and keep it heated fairly consistently. A dual boiler includes two boilers; one for making coffee and one for steaming. Heat exchanger models use a single boiler but are designed to produce coffee and steam at the same time. 

The pressure the pump exerts when pushing hot water through the ground beans; measurement given in 'bar'. Some trial and error with the pressure and grind is required. A high bar does not necessarily mean a superior machine. We optimise the machines before giving them a taste test to give them their best chance.

Whether the machine comes with a milk jug for frothing or not.

Manual machines generally contain integrated milk frothers. Capsule machines often have a separate milk frother which you either need to buy separately, or as part of a bundle. Some capsule machines use milk-based capsules.

Some capsule manufacturers provide a recycling scheme.