When boiling is done we need to filter wort becouse there are many particles inside. That is why we stir a wort to create vortex. So, a centrifuge concentrates those solid particles on one part of kettle – bottom. We can also add hop at this stage, this is the moment when wort cools a bit.
Usually we make whirpool:
- when wort is not cooled yet – we make whirpool as soon the boiling is done, wait for 20 to 30 minutes and use counterflow or plate chiller to chill the wort during racking to primary fermentor.
- when wort ia already cooled – we make whirpool after we have chilled wort with an immersion chiller, wait for 20 to 30 minutes (be careful for infections!). Rack to primary fermentor.
Whirpool when wort is already cooled: