[pmarcelll]

Pressure is not an issue since a vibratory pump in the most basic espresso machine can produce 15 bar of pressure quite easily. In fact, manufacturers have to put an overpressure valve in their machines to limit maximum pressure to the optimal 9 bar.

Also, this project is about sophisticated temperature and pressure/flow control, something even many/most professional machines simply can't do. So I really don't think the person who built this machine lacks experience in brewing coffee.

[andrewxdiamond]

Pressure is resistance to flow. In the aeropress, the coffee and the plastic filter screen resist flow and thus create pressure.

Not very much pressure, but there is pressure