Quick answer: On the Barista Express BES870, Breville lists a cold cup, cold portafilter, cool milk, scale and the water-temperature setting as separate causes of coffee that is not hot enough. Warm the cup and portafilter first. Compare a straight espresso before adjusting the machine.
Which drink is cool?
If espresso tastes hot but a latte tastes cool, check the milk rather than changing extraction temperature. If only the first shot of the day is cool, cold metal and ceramic are more likely. If every straight espresso is cool despite preheating, move to the temperature and maintenance checks below. When the machine itself never reaches ready status, use the BES870 not-heating guide.
What you need
A heat-safe cup, hot-water outlet, clean dry cloth and your normal coffee recipe. Beware hot water and metal. Keep hands clear of the group and steam wand, and do not remove the case to test temperature.
Run one controlled comparison
- Wait for ready status. Let the machine finish warm-up. Compare the same coffee and cup size on each test.
- Warm the cup. Rinse with hot water from the outlet and place it on the cup-warming tray, as Breville directs. Discard rinse water before brewing.
- Warm the portafilter and basket. Rinse them with hot water, then dry both thoroughly before dosing. Breville warns that a wet basket can encourage channeling.
- Try straight espresso first. Taste promptly. If it is satisfactory but a milk drink is not, address milk temperature separately with care; do not heat milk beyond safe handling.
- If still cool, review maintenance. Follow the BES870 descaling guide when due. Then, if your exact BES870 manual has Advanced Temperature Mode, consider a small increase, retesting the same recipe. The cited manual allows ±4°F in 2°F increments; it is a recipe adjustment, not a repair for a failed heater.
When service makes sense
If the machine never heats, the ready lights behave abnormally, or water and steam remain cool despite normal setup, stop treating it as a cold-cup issue. Do not attempt electrical or thermostat work without a qualified repair process. If extraction is also very slow, diagnose water flow separately.
FAQ
Should I turn the temperature up immediately?
No. First remove heat loss from the cup, basket and milk. The setting is useful only after a comparable straight espresso still needs adjustment.
Does a cleaning tablet cycle descale the machine?
No. Breville describes cleaning and descaling as different maintenance tasks.
Source
Breville BES870 instruction manual, “Coffee not hot enough,” pre-heating and Advanced Temperature Mode. Confirm your variant and control layout.