Since a few days I am the proud owner of an Expobar Brewtus IV (-P, used with the reservoir if that is of interest). It replaces my P.I.D.'ed Rancilio Silvia and although I still have to learn the machine a bit more, I am already getting rather good results with it.
I noticed that it takes a bit more time before the espresso comes dripping through after the pump is activated than with my Silvia and already read that that has to do with the pre-infusion. In another thread here I read a reply from another_jim where he mentioned 6-8 seconds. With my machine however it takes around 12 seconds. Now I wonder if that can be correct.
(Btw, in a review on a Dutch site they even mentioned a time of around 15 seconds).
Thanks in advance for a reply.
Ton

Assuming your grind is ok and that you are in the surroundings of a 2 oz double in around 25 seconds.

Part of the delay comes from the E61 pre-infusion chamber. From memory, it should lead to something like a 6-7 seconds delay (someone with an E61 might chime in to confirm/correct this).

Part of delay comes from the head space between the coffee puck and the group screen (which will vary depending on the dose used). The more head space you have, the more time it will take to fill in before the water starts to push through the coffee bed. The duration of this phenomenon will also depend of the flow provided by the machine (presence of a gicleur, for example, which would slow the flow).

Thanks Louis for your reply.
My shots are indeed around 2oz in about 25 seconds.
I use a VST 17-19 grams basket and I weigh the grinds to be 18 grams, so the basket is not filled completely to the rim. So that might be the cause, because there is of course a bit more headroom then.

Hi there,

I have an e61 and when using an 18g VST basket with a 19g dose, i usually get around 5-8 seconds before the first drops appear, depending on the beans and grind.

As mentioned earlier, concentrate on your pour time and yield (and taste!), that is what is important in the end.

Hi

Don't know about the tank version, but the BIII plumbed version is ~4-6+ seconds controllable with the mid position of the lever. That is, in the plumbed version, you can make the preinfusion last as long as you want by holding the lever in the mid position (pump off). You can also adjust the preinfusion pressure (line pressure).

Cheers