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Does anyone know when timing for a shot, do you take into account pre-infusion? Some machines can give as much as 3 seconds pumping.

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Generally yes, as this is water contact time with the ground beans


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I don't really understand "pre-infusion" It's just the time it takes for the water to saturate the puck, and find the path(s) through, isn't it? Surely it can't be controlled by the machine? When you press the button, the water is flowing at the same rate from the start to finish, right?

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As soon as I switch the pump on, I count to 4 and on the count of 4 the coffee normally comes out. Anything before or after that, I know its a dodgy shot!!


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In some equipment there is a separate preinfusion phase, where the puck is exposed to water but at lowered pressure. So it's true "pre" infusion rather than just part of the regular infusion.

 

With our consumer-level equipment the pump usually is not capable of moving a lot of water very quickly, so when it encounters an obstacle - the puck - it takes a little bit of time for the pressure to build up to its nominal level. That too can be considered preinfusion, though it's a different sort -- pressure ramping up steadily, rather than low pressure and then high pressure.

 

FWIW with my machine and my standard dosage of my regular coffee, for my tastes (syrupy but still sweet ristretto) seven seconds or just a hair more to first drop is the sweet spot. Five is a drinkable but undistinguished not-very-ristretto shot. Nine is a drinkable ristretto but with significant harsh notes. But Sandy and I use different machines and different coffees, and probably have different tastes, so it would be kind of weird if our timings happened to match.

Edited by ChiarasDad

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As soon as I switch the pump on, I count to 4 and on the count of 4 the coffee normally comes out. Anything before or after that, I know its a dodgy shot!!

 

I agree with that. More than a few seconds and the machine is choked. Less than that, you'll have 150ml in 20 seconds.

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Ive got a Giotto Rocket which is an E61 group head. Had it a while and only just found out about pre-infusion while reading a bit about the FAEMA original. My instruction manual said nothing about it.

So, I know nothing about pre-infusion other than the reason for doing it (this is explained in loads of places) but how to do it seems to be eluding me. How long should I do it? With it being none pumped on my machine, do I take the infusion time away from the pull time or add? Any info greatly appreciated.

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This issue confuses me too. My machine pumps for a few seconds, pauses & kicks in again after 6 to 7 seconds. If I include this in a less-than 30 sec pull, that accounts for around 20-25% of the pull!

 

Kind of important when you're chasing such an exacting time-to-volume ratio.

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Well, Glenn helped me out here and told me to add a 3-4 second pre-infusion by half opening the lever in addition to the normal shot pulling time. The idea being that the coffee is wet and so expands, so when the pumped water comes through it hits a puck that has a more even consistency.

However, I tried it for the first time this morning and it seemed that it had the opposite effect. Im blaming myself obviously, but for some reason the shot after infusion came through very quickly. After extraction, the puck came out easily, evenly and fairly dry but the espresso was lacking in a good crema and tasted a little under-extracted.

Its the first time I tried it so I have a lot more fiddling to do- grinder setting and so on.

Ill try to put up everything I learn in here.

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Grind finer in this instance and see what happens


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What is the general rule of time for coffee to appear here then? When I pull a shot it usually takes between 6-8 seconds for the pour to become visible and around 22-27 seconds for 60ml. I am timing my shots using a stop watch so those times are pretty accurate and I'm now getting pretty good shots (well I thought I was)


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Thats about right for a Rancilio Silvia / Gaggia Classic and other machines of a similar design


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With my limited knowledge. chriscoffee web site advertises a La Cimbali DT1 machine. This machine has the capability of pre-infusion. It looks to me like the group on this particular machine fills with water and after a few seconds the pump kicks in. That's my understanding.

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