Shots suddenly started blowing out - Page 3

Beginner and pro baristas share tips and tricks for making espresso.

#21: Post by chipman »

WDT tool? I just bought a little cocktail whisk and cut the ends off. works like a charm. Added highlight is that the wires are retractable. They can be spread as wide or narrow apart as needed.

Interesting to me at least, is that since I've been using my Key with the magic tumbler, I haven't had to use WDT once in the past three months.

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#22: Post by Nunas »

ZebcoKid wrote:"*9 acupuncture needles in a 3D printed handle available in a number of Etsy shops" I used acupuncture needles and a wine cork. I have a drill press, and just drilled some fine pilot holes in a pattern matching the commercial tools. Works like a charm. And...looks super next to my elegant espresso machine...revealing my true cultural roots!
0.4 mm 3D printer nozzle cleaning needles work well for this too. Wine cork (used, free, needles, cheap as chips online). Nothing more needed, except maybe to blunt the needle tips a bit, so they don't catch on the little holes in the bottom of the basket.


#23: Post by Giampiero »

Does the issue began after you installed the flow valve or the machine comes brand new with it already?

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#24: Post by borrik »

Per my experience, such "wild" shots could be related to short development phase and/or too low drop temperature. If you still on track with your home roasting, try to increase development phase for additional 40 seconds and drop at higher temp as well. Grinder will work much faster with less resistance and puck preparation will be much easier because of more "powdery" grind.

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Kaffee Bitte

#25: Post by Kaffee Bitte »

I have been using a wine cork with six small sewing needles as my wdt tool for years. Never saw a need to buy a nice one.
Lynn G.
LMWDP # 110

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#26: Post by borrik »

Plain needles should be used very carefully because they could damage the basket holes and cause permanent uneven extraction, especially if basket has flat (unstamped) inner surface that is very sensitive to mechanical damage. I'm using some twist needle tool with adjustable depth to eliminate the risks.


#27: Post by HeinK »

Have you checked your shower screen? It could be that coffee grease partially blocks the holes, which can lead to channeling in the puck.

Benos (original poster)

#28: Post by Benos (original poster) »

After my last post, shots continued to randomly blow out. After testing and replacing everything possible, I called WLL for a tech call, but was routed instead to and email exchange. Which turned out to be completely useless.

I had a feeling the rotary pump was the problem, because it would not stay in any sort of consistent adjustment. As the days went by the pressure would rise from 9 bars up to 12+ bars. I'd set it back to 9 bars, then the pressure rise would repeat.

So called WLL again, but this time spoke to the sales department. I described the issue ... and told them I wanted to buy a new pump. And the guy was kind enough to sell me one at 50% off retail. After replacing the pump, I'm back in business. Perfect shots. Shot after shot, day after day, not a bit of pressure fluctuation.


#29: Post by GDM528 »


So, rapid pressure bursts were fracturing the puck and creating channels for the blowouts?

Benos (original poster)

#30: Post by Benos (original poster) »

Maybe. I can't imagine how that pump could cause the blowouts, but replacing it fixed it for sure.