Pre-Infusion Equals Fast Shot?

Beginner and pro baristas share tips and tricks.
BillF

#1: Post by BillF » Jun 11, 2019, 12:57 am

I have a Profitec Pro 700 and I have noticed when I pre-infuse for maybe 6 seconds a shot that normally pulls in 30 seconds will finish in about 20-21 seconds. So the thought occurred to me what if I ground the beans finer to slow the shot down would that result in more tasty cup because of the pre-infusion? I drink flat white or latte's type drinks usually.
BillF

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Jake_G
Team HB

#2: Post by Jake_G » replying to BillF » Jun 11, 2019, 1:08 am

That's the idea.

I'm generally a fan of some duration of preinfusion, but it would be an oversimplification to suggest that all beans will taste better by grinding finer.

A better way to look at this is that you can control the amount of extraction by adjusting the balance of preinfusion duration and shot length with grind level. Some coffees taste better with a higher level of extraction, and others taste really bad when extracted beyond their sweet spot. I suggest grinding finer and noting the difference. Then preinfuse even longer and grind even finer. Eventually, the coffee will get astringent and you'll want to back off the grind and and preinfuse less to get a better tasting shot.

Over time you'll find that some coffees have a wide window of tasting great, and others are much more narrow. Also, some coffees taste very different at different extraction levels, and others taste very similar non matter how you pull them. Then there's the matter of adjusting brew temperature to see if you can unlock magical flavors from a coffee that has been moved outside the sweet spot by grind and preinfusion.

Welcome to the boss level of espresso enjoyment. :wink:

Cheers!

- Jake

Lateralus

#3: Post by Lateralus » Jun 12, 2019, 12:51 pm

Try new things! Just change one thing at a time to know what helped if you get a good shot. Tightening up the grind is a good place to start.

I'm assuming you're plumbed and running on line pressure. Do you have a bottomless portafilter?

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cannonfodder
Team HB

#4: Post by cannonfodder » Jun 12, 2019, 3:14 pm

My machine comes to full pressure in just over one second. I use 5 seconds of pre infusion under 2 bars of mains pressure to gently ramp up the pressure and give the puck a moment to settle in and swell before hammering it will full 9 bars. It tends to give me a more defect free shot. What causes that, do not know. Could be the fines migrating to the point of least resistance inside the puck and slow down the flow in that spot. I attribute the change in in flavor to the more uniform flow through the puck.
Dave Stephens

grover

#5: Post by grover » Jun 17, 2019, 12:31 pm

I'm completely new to pre-infusion as I've only had a machine that goes to full pressure. So I am to assume even if I doing a 4 second pre-infusion the overall shot time should still be the same?

liquidmetal

#6: Post by liquidmetal » replying to grover » Jun 17, 2019, 1:47 pm

I think most people would suggest that if you're pre-infusing, you don't count your "shot time" until you are done preinfusing + liquid is hitting the cup.