Filter brewing
Preheating a brewer
Small brews lose a surprising amount of heat into cold ceramic, metal and glass. Warming everything first costs ten seconds.
- Skill level
- Beginner
- How long it takes
- Ten seconds
- Equipment needed
- Pour-over dripper
- Steps
- 3
Why it works this way
A 250 ml brew has very little thermal mass, and a cold dripper, carafe or cup has quite a lot. The result is a brew that starts at the temperature you chose and finishes several degrees below it, which shows up as sourness and thinness that no grind change quite fixes. It matters most for small pour-over brews, for manual espresso devices, and for any drink served in a cold cup — including a flat white, where a cold cup can take a noticeable amount of heat out of a small volume of milk.
What you need
Required
Helpful, not essential
How to do it
Run hot water through the brewer and into the serving vessel.
Combines with rinsing the paper if you are using one.
Discard the water immediately before brewing.
Warm, not wet, is the goal.
Warm cups for espresso and milk drinks too.
A cold cup is the most common reason a correctly steamed flat white arrives lukewarm.
How to tell it worked
A brew that tastes the same at the last sip as at the first, and a milk drink that stays comfortable to drink for longer.
If it did not work
What you saw, what to change, and why the change works.
Coffee tastes thin and sour despite a reasonable recipe
Change: Preheat everything and brew again before changing the grind.
A temperature drop through the brew presents very like under-extraction.
Common mistakes
Preheating and then leaving everything to cool while grinding
The benefit is gone by the time brewing starts.
Instead: Preheat last, immediately before brewing.
Diagnose a specific problem
The science behind it
- Water temperature
Brewing water is typically just off boiling — too hot or too cool both cause problems.