The boiler is the heart of an espresso machine. It controls heat, pressure and how quickly you can make milk drinks.
Single boiler
One boiler heats water for both brewing and steaming. You must wait between the two tasks. These machines cost less and take less space. They suit people who drink a few espressos a day.
Heat exchange
One large boiler holds steam. A pipe passes through it to heat brew water on demand. You can brew and steam at once.
Heat exchange machines need a short “cooling flush” before brewing. Skilled users get excellent results. Beginners may find temperature tricky.
Dual boiler
Two separate boilers handle brewing and steaming. Each holds its own temperature. This gives the best stability and speed.
Dual boilers cost more and need more room. They suit those who make many milk drinks or who care about precision.
How to choose
Count how many drinks you make in a morning. One or two points to a single boiler. Four or more points to heat exchange or dual.
Whatever you choose, descale on schedule. Scale is the most common cause of machine failure.
