Long story short: I bought this kenyan back in january, only to find that its super tricky to work with. Since then I have had it in my thoughts and last week I bought it again. This time I think its even more crazy then last time. When i grind finer, the shot time goes up. Every coffee I have tried have followed this rule (only crazy channeling can change that rule).

When im pulling this kenyan roasted 24/4 from a well known local coffee shop, I use a vst 18g basket, aerofilter in the bottom (really like results of this, and it helps to slow down the shot i think), flow profile that i picked up by one of you in here, have got really nice results with this recipe. 8ml/s to 2 bar pressure in the grouphead, 4ml/s to coffee shows under basket, stop flow 10 sec and then back to 8ml/s to 1:2 ratio is achieved.

Normally i find my taste favour shot time around 40 sec, included pre infusion. With this shot the flow is crazy high. 1:2 ratio in maybe 9-10 sec without pre infusion, and as you can see in the video, high flow with pre infusion.

I have grind alot finer then usual. Mye usual setting is around 1, andre im now at 0,5 ish. Compared in the i normally use 4,5 sec to grind 18, and im now at 7,5 sec. Taste wise the shot is ok, its naturaly really fruity, but the shot is ok balanced, missing some clarity, a little thin in flavor, but if anything more on over extracted side then under.

I have tried grinding finer, resulting in more or less the same time, but more channeling and weak and bitter taste. I have also tried grinding coarser, resulting in even faster flow and under extracted taste.

Have you any suggestions whats off, and what I can do to get more juice out of the beans? Or do I just have to live with that this is the best i can do and probably never buy the coffee again and try to forget its existence?

The grind is too fine leading to channeling? Or maintain the grind and using a smaller dose?

Try a standard basket and tamper. With that fine grind in the VST you should be using a distributor with no tamp. I'd guess you're tamping that fine grind into something as hard as clay and the puck starts breaking up and channeling under pressure.

Maggiekw wrote:8ml/s to 2 bar pressure in the grouphead, 4ml/s to coffee shows under basket, stop flow 10 sec and then back to 8ml/s to 1:2 ratio is achieved.

Those may be positions of the valve, but as soon as there is backpressure from the basket, the flow rates aren't what you quoted.

Watching pressure during extraction is perhaps a better thing than the position of the knob.

As it looks like the shot falls apart quickly in the video, I would try "back to basics" and then adjust your technique and profile from there.

I'd try a moderate grind with your stir-to-level and tamp (assuming you don't use a leveler - don't, if you were). Leave off the bottom filter. Try a moderate-flow basket fill, pause for a few seconds once full, then ramp up to 6-7 bar in the basket. Perhaps ramp down a bit, watching the pressure gauge, from during extraction. Adjust the grind, as needed.

I use wdt to level (no distrubutur), tamp.

I tried what you suggested, both with and without pre infusion. It seems like the synchronika cant build pressure above 7 bar. Pressure begins to drop from that point. So the puck either 1. Falls apart, 2. Insane channeling, 3. My grinder cant handle this coffee so the result is particles that are so uneven that the flow will never be uniform.

I have tried grinding coarser, the flow increase. The taste is kinda right, but weak. If I grind finer you see the result in the video. I usually dont have much problems dialing in, but this coffee is a nightmare. Can it be the roast?

Have you tried updosing to increase puck resistance instead of grinding finer?

I have tried 19g in a 18g vst basket. No noticble affect. My toughts was that this might increase the chances for channeling. Therefor the aeropress filter in bottom, that kinda slows it down.

I dont know what more else to try. Waiting for my new lagom p100, will for sure buy the same coffee to see if its the coffee, grinder, or me. Just weird it only happens with that bean.

Maggiekw wrote:Just weird it only happens with that bean.

Nothing weird at all. Every coffee is unique and dosing / grinding to spec in a single basket type is a sure fire way to frustration.

Try a different dose / grind / basket until you like the taste. Keep notes so you can quickly get back next time you brew an outlier.

Before we start talking about puck preparation or wdt eccetera I would want to know the roast depth of the beans (light or medium or dark would suffice) and the roast date. Until I had that information it's pretty difficult to diagnose anything.

It could be that you provided that information already and I simply didn't see it as I read through so please forgive me if this is out of place.

What would also be helpful is to know also the brew temperature because that affects quite a lot relative to light roast vs dark roast.

I mentioned that the beans was roasted on 24/4, but the beans was like that from the start (2/5). It is a light roast. On my synchronika It says 96 Celsius, but I havent measured the actual temprature that comes out. Dont know how precise it is? Im empty for the beans now.