The pre-Christmas rush provided me with a lot of hard work and a good deal of food for thought. The background to this article is simple; in early November I received a long awaited shipment of  expresso machines at the same time that I ran out of stock of other machines. In the following 6 weeks I set up and tested, in batches of 6 at a time.

Temperature

All the components used in brewing, machine, porta-filter and filter baskets, need to be at a stable temperature. The best way to achieve this is to let everything heat up together for at least an hour. Leaving the machine on overnight or longer is not a problem as long as the boiler is full and there are no leaks from the steam wand, solenoid etc.

Quantity

A little bit more or less coffee makes a huge difference. Once I’d worked out the temperature thing, this turned out to be the biggest single source of variation.