Cooling Flush Myths

Cooling Flush Myths & Misconceptions

Just a few things to cover here

1. The cooling flush cools (and is to cool down) down the E61 group

no it doesn't the group is not as hot as you think. At the bottom of the group (where the portafilter locks in) the temperature is approximately 80C…this will of course vary with different machines, but not by that much.

2. The cooling flush should always be X oz
no this isn't true either, it will depend on the boiler pressure you are running at and the ambient temperature to a small extent

3. The machine should be flushed until the water dance stops and you get a steady stream
This is only partly true, depending on the machine and the taste of your shots… may or may not want to do this. The main objective is to get some or all of the very hot water out of the HX unit. However you may find that flushing a few OZ and stopping before the water dance ends, may give better results for your machine…..always be guided by taste

4. Scaling of my machine doesn't affect the cooling flush

Oh yes it does….big time, as the machine scales, the transfer of heat across the heat exchanger becomes much more innefficient, you may not want to flush as much if your machine is scaled. This of course is a compromise as the water will be initially too hot and later too cool