I think my regulator will max at a little higher than 15 psi. My line gauge also reads only up to 15 psi.

I turn the regulator up and my gauge pecks. But when I do a middle lever shot it goes down to 14 psi. When I do an upper shot the gauge now reads 12.5 psi. I could change in the future to a higher regulator but I did another hybrid shot and it all taste good.

I think other people may have higher setting for the regulator than I do but I could try to change the bypass valve and see what happens

Cheers

That's what Ken and Jim concluded in How to Preinfuse; Extraction Pressure Redux, i.e., a few seconds of preinfusion at 3 bar made a positive difference for some coffees. See The Impact of Preinfusion on the Taste of Espresso Shots for their test results.

Dan. Thanks for that link

Just in case and for the goodness of human kind, tomorrow I'll do naked portafilter shots to see if mine also come from the side of the basket at low pressure.

Cheers

OK. I tried to verify the low pressure side channeling and this is what I got. The low pressure makes everything go sloooow motion.

In a total of four attempts, I got the side channels to always wet before anything else. An even wet ring forms on the very edge but no drops. Soon afterwords, the wetness spreads towards the center and the first drops appear. The first drops start always from the edge at very low pressure.

Rafael's planet is full of bean challenges

Cheers

PS: Doses were always bellow 11 grams in double basket

Unless you have tasted shots from a paddle group machine I think that attempting to simulate the results will be somewhat challenging.

After playing for some time, I think long preinfusion benefits from grinding coarser than normal. The flavor is fuller, tastier, and enhanced in a good way.

It reminds me somehow of how a french press works, where you leave large grounds soak for 4-5 mins, except that here, it is only about 10 seconds.

If you have an E61 with spring preinfusion, you can duplicate the effect by cutting the shot before it builds full pressure and letting it soak for 10 seconds or so. Then pull a regular shot but it will be maybe only 15 to 20 seconds instead of the normal 25 to 30 seconds.

Cheers

Hi folks!!!!

This morning, my mind didn't want to surrender to the idea that water always comes first from the sides, as previously exposed in this thread. At to this point, till my eyes saw in slow motion (low pressure) a naked shot, I've been creating a perfect mountain centered in the middle, believing that long time of initial extraction was a good sign of proper distribution. But a perfect mountain has a peak which later becomes a higher pressure point, which in turn, makes water start to come out first from the walls. At higher pressures, this small difference in puck pressure is not as apparent.

I've initiated a personal search for a method to prevent this from happening. So far, I've experimented with dipping my finger in the middle of the mountain (prior to tamping) forcing a 'weakness' in the middle with the aim of having an equally timed extraction. It is too early to make any claims due to the practical difficulty of tasting minor taste differences. However, I've gain an awareness that I previously didn't have. Now the sides start first to wet but immediately the center follows and drops start even _at low pressure_ (and of course high pressure).

Cheers to all

and how did it taste

They taste good. It helps to bring good qualities forward.

I just made a video demo but with different times (longer preinfusion, longer extraction, and finer grounds) to show the formation of the ring. This video was made using the self inflicted weakness to equalize the extraction so that drops don't start on the edges at low pressure.

This is how a normal basket looks (~ 10.60 grams if that matters)



this is how an equalized basket looks like



Once tampered all baskets look the same



This is the video of that basket with the new preparation method (making a dimple in the middle).



Cheers

PS: This coffee was decaf somewhat old jeje