This optional chamber mimics the passive preinfusion you find on the venerable E61 group. The LUCCA A53 Mini and La Spaziale Mini Vivaldi II’s brew group is designed to make installing the preinfusion chamber easy and reversible. Instead of all the pump pressure flowing straight through the group head, the pre infusion chamber diverts some of the flow resulting in a gradual 6 second (not adjustable) ramp to full pressure. This saturates the coffee bed more gently to minimize channeling, making even extractions easier and shots more consistent! To learn even more, check out our article on pre infusion here.