Mypressi V2 + Preciso, Sour Shots

#1: Post by **bcx** » August 24th, 2013, 9:23 am

I keep making sour shots and from what I have read, that is due to underextraction. I'm using a Preciso on grind setting 10F and my water is hot enough. I've also preheated everything. I'm pulling 25-30 second 2oz shots with 20g dose, but it comes out sour. If I adjust to a finer grind then my shot takes much longer than 30 seconds.

Any suggestions?

Yes my beans were roasted within a week (Te Aro Diablo from Fahrenheit, and the shot I had at the shop was very tasty).

#2: Post by **jontyc** » August 24th, 2013, 9:43 am

Have you tried two or three preheats? Measuring the temperature of the chamber, I was amazed how quickly it drops.

#3: Post by **jedovaty** » August 24th, 2013, 8:04 pm

What Jonty said, preheat 2-3 times. If you are doing that, then also consider which beans you are using, some will be sour and the twist may not be able to deal with those. Try something else.

Another idea, try a double pull -- basically, squeeze the trigger and let go at the moment you see drops forming on the basket. Count to somewhere between 5 and 10, then pull the trigger again. BTW, I found when doing this, I had to coarsen the grind just a touch.

If even after the double pull you keep getting sour shots, then instead of espresso, consider making an americano; do an 18g coffee to ~30-36g shot over 25-35 seconds into 100-170g of hot water (by taste..). This has almost always mitigated sour shots for me and made for a surprisingly good tasting drink.

August 25th, 2013, 11:15 am

I'll give the multiple pre-heating a try. Do you have everything assembled (including coffee basket) when doing a preheat or do you just use the handle+water chamber?

August 25th, 2013, 12:07 pm

The most important item is the water chamber, and maybe just the ring part of the handle. I keep the water boiling, fill the chamber, empty after a few seconds, repeat, then fill with the still boiling water, add the filled and tamped basket, lock the water chamber onto the handle and press. I think that's the procedure from MyPressi blog. Works great for me on the road.

#6: Post by **MWJB** » August 25th, 2013, 12:50 pm

I wouldn't worry too much about sticking religiously to 30second shots (I have had delicious shots well beyond this, ultimately you need to put more water through the puck...if you're under at 30s, keep going), go by output weight. Are you counting from pulling the trigger, or from 1st drops?

+1 on the double pull on the trigger.

Also try dosing less.

I actually make singles using the single/pod basket more often than doubles, they have a thinner body and little crema (so not for everyone), I use a 10g dose, aim for 10g output...maybe run a few additional g each into a 2nd & 3rd shot glass and combine with the first glass if it's too acidic sour?

I find the Mypressi very consistent & pretty forgiving when you get the hang of it.

#7: Post by **jontyc** » August 25th, 2013, 7:31 pm

bcx wrote:I'll give the multiple pre-heating a try. Do you have everything assembled (including coffee basket) when doing a preheat or do you just use the handle+water chamber?

I actually pour the boiling water in the bottom of the chamber, keeping the lid sealed at all times. I had to do this to get around the problems I had with the lid o-ring expanding with heat and the showerscreen flap letting water through during preheating.

So everything is assembled except the basket and showerscreen assembly. The handle is especially important to survive the next 25-30 seconds.

#8: Post by **sgmonkey** » August 26th, 2013, 12:41 am

Used to have this problem until I recalibrated my Preciso to the second screw hole in the "Fine" spacing. I'm now at 10B/C and pulling shots that rival my favorite cafes.

I actually found that I have plenty of gas left over after pulling four doubles, so instead of heating multiple times, I actually do a quick "purge" of boiling water through the water chamber, shower screen, and empty basket. Just a super quick trigger pull. Works for me

#9: Post by **sgmonkey** » August 26th, 2013, 10:07 pm

So I just pulled what I think is my best shot ever on the Mypressi by changing my technique a bit.

Leaving everything the same as I metioned above, after getting the grinds in the basket and stirring it a bit with a toothpick, I first tamped at half my normal pressure (15lbs or whatever) and then did a minor nutation motion for 2-3 rotations, leveled off my grounds and checked the bed was flat and even, and then finally tamped at full pressure.

Did it a second time with same results. Try it for yourself!

#10: Post by **jontyc** » August 27th, 2013, 8:16 am

I remember my extractions always started at the perimeter of the basket and filled inwards reasonably quickly to give a central stream. It's hard to know whether I was getting some degree of overextraction and the perimeter, underextraction in the center.

I noticed mypressi promotional videos showed the same behavior, so assume it's the same with everyone, probably from the way the rubber flap disperses towards the perimeter.

Did you find with the nutation extraction still started at the perimeter?