Pre-infusion - good? bad? indifferent?

[nickR]

I've had a bit of a search but can't find much specifically here about pre-infusion, so thought I'd start a new thread.

The context - I have a EM7000 and have had for a long time, but for some reason have never played with the standard settings. By crikey, changing the steam settings makes a massive difference to milk texturing...

And now to play with the pre-infusion settings - this machine comes with 3 settings which I am currently testing out, a few days each, with different beans, to get a good idea of the outcomes/pros/cons.

But more generally, does pre-infusion have this mythical quality of something that "you should just do"? I have read all sorts of opinions in my google travels - everything from
- makes a world of difference
- makes no difference
- makes it more likely to get a decent extraction
- makes it less likely to get a bad extraction
- soaks and expands the puck, making for an even extraction
- why bother with exacting dosing/tamping/grinding if you are just going to flood the puck before extraction .....

and so on.

I have my views, and I'll also post my EM7000 specific thoughts and findings later, but just thought I'd open this up to other opinions first.....

[kwantfm]

I have a few preinfusion options on my machine. Firstly, I have a spring-loaded preinfusion chamber, secondly, I have a needle valve controlled mode that allows me to set the flow rate for pre-brew. I think there are two benefits to a softer preinfusion. The first is that I find that the process is more forgiving. I get beautiful pours from a bottomless PF every time. The other (and more important in my opinion) difference is that a long preinfusion allows me to grind finer and still have the same extraction flow rate later on when I engage full brew pressure. This allows me to bring out different flavour nuances from the coffee. I roast at home and therefore generally have three or four single origins available at any one time and I find that a long preinfusion highlights the differences between different origins.

[TampIt]

+1 to kwantfm. As a long time Electra lever owner (20 odd years) preinfusion can make a huge difference. Depends on the roasts, your setup , skill level etc etc.

I also have a 7000 - I often trick it by flicking the pour button twice (play with the timing, you will get the idea) to start the preinfusion and immediately stop the shot. After the time delay of your choice, hit manual and stop it when / before it blonds. Makes a lot of difference to some roasts, very little to others.

Being "old school", I haven't bothered to use the 7000's presets... perhaps I should.

TampIt

[Jono_Willmer]

This is something I have just started to play with and looking for some answers. When using pre-infusion on a GS-3 I have been allowing the line pressure to wet the puck until I see the coffee come through the filter in a naked portafilter, then I activate the pump and pull my shot around 25-33 secs pour after pre-infusion for a 35-45 gram pour. If I try to activate pump straight away it basically chokes and the pour becomes massively over-extracted trying to get a similar 35-45 gram double. I would have to grind so much courser to not use pre-infusion. Is this typical and actually the benefit of pre-infusion being able to grind finer?

[TC]

Yes Jono- experiment with finer, lower doses using the strategy you have been using.

(PS- the rest of the black in transit to you....)