Breville Dual Boiler - Pre Infusion - Is this normal?

#1: Post by **wouterdr** » September 19th, 2021, 12:13 pm

Hi all,

I received my Breville Dual Boiler this week as an upgrade from my trusted Gaggia Classic.

Hence, this is my first machine with pre-infusion, so I was wondering if what I'm seeing is 'expected'.
In the video I am showing the flow and pump activity during pre-infusion.

During the pre-infusion (currently kept at stock at 60% in the BDB, the flow of water is very minimal, and there is no pressure being built up in the puck at all.
(Yes, I am talking about when pulling an actual shot, not without anything in it as shown in the video).

FYI: the actual shot is currently dialed in to about 1:2 in about 30s, so it is not that it is choking. The pre-infusion at the current grind setting does not produce anything yet, it typically takes another 3 seconds at full pressure post that. Bottomless portafilter has been ordered, so I don't really know what is happening with the bed at this time.

Thanks,

Wouter

#2: Post by **lancealot** » September 19th, 2021, 1:26 pm

Looks right to me. The flow is so slow that in order to get pressure to build up, you have to extend the preinfusion time to something very long. Which in many cases is unnecessary.

I'm my opinion, Breville should call their preinfusion "adjustable water debit" rather than "adjustable pressure."

#3: Post by **coffeechan** » September 19th, 2021, 1:56 pm

This is normal for stock factory. Pre-infusion time is set to 7 seconds. You can press and hold the Manual button to control the pre-infusion time then release when you want the pressure to build to 9-10bar on the gauge which the OPV is usually set at. Depending on how fine your grind is, first drops for me usually appear at the 13-15 second mark if you decide to extend pre-infusion. The merits of how much pre-infusion has been debated in the past and can be searched for. Consensus is to stretch out the pre-infusion for light to medium hard to extract coffees and to cut down on it for darker roasts.

Congratulations on your upgrade. The BDB is a capable machine that will serve you well with many a tasty drink. I'd recommend reading and reinforcing how to manipulate extraction parameters to get the most out of the machine.