These get talked about like two rival technologies, but they're not quite that separate. Here's what each term actually means, and why heat-up times vary so much even between machines using a similar approach.
Thermoblock is the general, industry-wide term for a heating system that warms water as it flows through a metal block with an embedded heating element, rather than storing a reservoir of hot water the way a true boiler does. Several manufacturers use some version of this approach, including DeLonghi, whose Dedica uses a Thermoblock system that reaches temperature in about 30 seconds.
Because it's a general category rather than one specific product, heat-up times and performance vary between different manufacturers' implementations, even though they're all described with the same word.
ThermoJet is Breville's own branded version of this same basic idea, engineered specifically to heat much faster than a typical thermoblock. It's consistently reported at about three seconds to reach brewing temperature, which is fast enough that some machines skip a dedicated warm-up step entirely.
So the honest answer to "ThermoJet vs Thermoblock" is that ThermoJet is a thermoblock, just a specific, faster-engineered one that Breville uses across several of its machines, including the Bambino and Bambino Plus and the Barista Pro. It's not a competing category so much as a faster entry within the same one.
Thermocoil is a third term worth knowing, since it shows up on some Breville machines like the Barista Express. It heats water through a coiled element rather than a solid block, and it's generally slower than ThermoJet, though published heat-up figures for it vary quite a bit depending on the source and what exactly was measured.
Breville has moved toward ThermoJet in its newer machines, with Thermocoil showing up mostly on older or lower-tier models in the lineup.
For convenience, yes, genuinely. A three-second heat-up means you can decide you want espresso and have it a minute later. A slower system asks you to plan a few minutes ahead, or accept a short wait.
For the espresso itself, not really. Once any of these systems reaches its target temperature, the water going through the group head is doing the same job. Heat-up speed is a convenience question, not a shot-quality question.
| System | Maker | Approx. Heat-Up | Used In |
|---|---|---|---|
| ThermoJet | Breville | About 3 sec | Bambino, Bambino Plus, Barista Pro |
| Thermoblock | DeLonghi (and others) | About 30 sec, varies by implementation | Dedica |
| Dual Thermoblock | DeLonghi | Varies, allows simultaneous brew and steam | La Specialista |
| Thermocoil | Breville | Reported figures vary widely by source | Barista Express |
Functionally, yes. Both heat water on demand rather than storing a reservoir. ThermoJet is Breville's own branded implementation, engineered to heat much faster than a typical thermoblock, but the underlying concept, heating water as it flows rather than storing it, is the same.
Thermocoil is another Breville-specific system, used in machines like the Barista Express, that heats water through a coiled element rather than a solid block. It's generally slower than ThermoJet, though exact heat-up figures vary across sources.
Not directly. Heat-up speed affects convenience, how long you wait before your first shot, not the quality of the espresso itself once the machine is at temperature. A slower system that's fully warmed up makes espresso just as capable as a fast one.
Often because sources measure different things. Some report when a ready light turns on, others measure when the machine reaches full, stable temperature throughout the group head, which can take noticeably longer even after the ready light appears.