Just saw a couple youtube videos where people were incorporating a preinfusion, I'm curious if anyone on here has experimented with it? What's the ideal preinfuse time for a double shot?

Thanks for any suggestions

No such thing as an "ideal" pre-infuse time as it's all personal taste.

If your machine has a rotary pump and is plumbed in you can slow down the pre-infusion by only lifting the lever halfway up to engage the line pressure. Minimum time on an E61 such as yours is about 6 seconds, but by only lifting the lever just over half way, you can extend this to whatever you'd like. Finish the shot by lifting the lever all the way to engage your pump to ramp up the brew pressure to whatever you have your OPV set to.

Have fun exploring what works for you.

Cheers!

**edited to reflect plumbed-in rotary machines**

Thanks for the quick reply Merle. So does the ~6sec pre infusion time count in the 25-27sec extraction time??

CelliniEVO wrote:Thanks for the quick reply Merle. So does the ~6sec pre infusion time count in the 25-27sec extraction time??

Yes, most will consider it in the shot time. But regardless of what others do, tweak the shot to fit your taste buds. For instance, if you pre-infuse for 12 seconds, you can't really still shoot for a 25 second shot and expect the same as one pulled by flipping the lever all the way up right from the start. Just be sure to cut the shot off when (I prefer before) the espresso starts to blonde.

First, all manual (lever) E-61's have a basic preinfusion built in. It is explained and fully illustrated in the new Vibiemme Domobar Double "DD" owners manual available HERE. I am not sure about the versions of the group which are electrically controlled.

For rotary machines that are also plumbed, raising the lever to just past the first point of resistance opens the brew valve and allows the line pressure to push water past the pump and into the group at line pressure. As long as the lever is held in that position, water will flow into, and eventually through, the coffee. There is no rule as to how long, but I have found that when the first drops fall into the cup is a good time to stop. You can start with about ten seconds.

I quit using a clock to time shots a long time ago. The critical timing is for shots that happen too fast (there is a radical photographic example of that in the above-mentioned owner's manual). I have had excellent extractions that took 40-45 seconds. A few even longer.

Randy,

Great catch on the "plumbed in rotary machines". I omitted that in my original post but went back and edited it.

Also, nice to see someone else put aside the timer for shot duration. Like you, I've had many outstanding shots that went well over 30 seconds.

I have experimented with a vibe pump by adding a resistor and switch in line with the pump. It allows the pump to run at low power where water pressure stays very low. I usually go about 5 seconds before I release the switch and let the pump go back to full power. It does seem to make the start of the extraction a bit smoother as the puck has had a few seconds to get wet and expand before the pressure hits it.

If everything else is kept the same, preinfusion time is dependent on your line pressure. The practical way to determine the time, already mentioned, is to lift the lever to the preinfuse position and see how long it takes water to start coming out of your basket (preferably) or coming out your spout. Use that time, or perhaps a little less. Regulating the line pressure going into your machine is usually a good idea. Seems like you have a lot of good info in the foregoing; hope you get great results.

Regulating the line pressure going into your machine is usually a good idea.

I could not agree more! In my (regulated) 60 psi home water system I initially installed a lower-pressure (30 psi=2 bar) regulator on the espresso machine branch, just to be kind to the equipment and to stabilize supply pressure at a reasonable and constant value, since pressure applied to the coffee changes with water supply pressure. Good enough, but only later, when I started playing with preinfusion, did I come to appreciate the value of being able to adjust the preinfusion (line) pressure. This came after many preinfusion experiments at my chosen default 2 bar pressure, with equivocal results. Disappointed so far, I upped the pressure to 3 bar, and began to see unmistakable and consistent effects. This pressure was enough to cause bleed-through, previously unobserved, in 5 to 10 seconds, which may be a useful guidepost. Some timing parameters are necessarily tweaked when preinfusion is inserted into the process. This has pushed me to ignore the timer and watch the shot, as another poster noted. Not that the overall shot time increases that much: I have noticed that after the no-pour (preinfusion) phase, turning on the pump results in a slightly faster flow than was my normal, but that flow is rich and thick, and I like the results, both in terms of increased richness in the cup, and reduced channeling, even with the fickle (for me) LM single. In sum, pressure regulating began as prudent insurance, but morphed into a useful tool for exploiting a brewing dimension new to me: preinfusion.