Currently in talks with option o because I've been having similar issues with inability to grind fine enough. Most beans are between 0.1 and 0.3, but I just had a light roasted Mexican anaerobic and grinding at 0.01 from chirp and at max RPM was a 20 second 2.5:1 ratio shot.

einholen wrote:Just got a brand new P64 with Mizen burrs, and so far it can't even grind fine enough for espresso - I hear burrs starting to chirp at 0 (and can't go below), but at half a tick (0.05?) my shots are fast and peak at 5 bar, whereas I had no problems getting to 7-9 bar grinding this coffee with NZ. Reading this thread I see reports that folks get proper shots anywhere between 0.5 (5 notches) and 2 (20?!) - so my situation does not sound normal, right? Not finding any shims in the box.

What dose, basket, and rpm are you using?

GDK wrote:Almost certainly sounds like your grinder needs the ticker burrs or shims. Can you take off the upper burr carrier and see if the inner surface that is around the upper burr is scratched?

Let me clarify as my statement may not make much sense w/o this. What you likely hear is not the burrs touching but the three teeth that protrude around the lower burr touching the ceiling of the upper carrier, hence the scratch marks you can see to prove it. This simple check may facilitate the communication with Option-O. Not only they sent me the ticker burrs, but also an upper carrier as mine was scratched (minor) - what a service!

Wodan wrote:What dose, basket, and rpm are you using?

I've been brewing with 18 grams in a VST 15g basket at speeds 6-7.

I've finally been able to get to 9 bar - at grind setting 0.025 and speed 4, and reverting to a 20 gram dose in the stock BDB basket. Still a bit fast (20 in 44 out in 25 seconds) but it's at least in normal range, and mort importantly espresso was delicious! But obviously still concerning that I can't go finer.

GDK wrote:Let me clarify as my statement may not make much sense w/o this. What you likely hear is not the burrs touching but the three teeth that protrude around the lower burr touching the ceiling of the upper carrier, hence the scratch marks you can see to prove it. This simple check may facilitate the communication with Option-O. Not only they sent me the ticker burrs, but also an upper carrier as mine was scratched (minor) - what a service!

What are ticker burrs? I initially thought it was a typo from "thicker" but then you said it again

Agreed about customer service! I reached out to Option-O and got a very quick response, suggesting me to clean it and check whether zero is set properly. He said the issue is likely with the burrs if zero is set correctly, and they'd send me new ones.

LOL, two mistakes in a row... but they tick me off too sometimes when I pull shots with lighter roasts.

maccompatible wrote:Currently in talks with option o because I've been having similar issues with inability to grind fine enough. Most beans are between 0.1 and 0.3, but I just had a light roasted Mexican anaerobic and grinding at 0.01 from chirp and at max RPM was a 20 second 2.5:1 ratio shot.

How are the talks going?

I cleaned my grinder and after that was able to go from 0.025/20g dose to a whopping 0.1/18g dose for a proper extraction with the beans I currently use (Colombian anaerobic medium roast that kind of behaves like a decaf so a low setting is expected I think).

Update on my issue: it's the beans, plus seasoning plus maybe alignment which I improved just by opening the grinder (one of the screws might've been looser than the other?). I suspect it's normal that some light roasted or decaf coffees "reside" close to zero. It's also not surprising that NZ produces a more traditional espresso at these grind settings because it produces more fines. The coffee I've been using produces good espresso at 0.15 now (so it shifted up 0.05~0.1 as the burrs season). I also tried two more different beans by now, and they both dialed in at 0.5-0.7 which I think is good range. Thanks everyone!

Mine actually worsened after putting coffee through them. Now the smallest amount above chirp produces a turbo shot for light roast. And medium dark is being pulled at 0.1 to 0.2. They said they think the burrs are the problem and they're going to send a replacement.

Thanks and please share developments!