I don't know much about horses, but I've been given to understand that dead ones do not respond to even the severest of beatings.

Disclaimer above. I have had countless grinders over the years and just added to my arsenal a Eureka Zenith 65. The burrs are as they were when they left the factory - rough and unseasoned. In my joy and impatience, I took the best coffee I have and went ahead and pulled a shot. It tasted beautiful. The taste was not what got me puzzled.

After a few pulls and getting the grinder where I wish it to be, I found that the consistency is all over the place. I'd pull a shot and be forced to adjust the grinder two shots later - several times during the same session. I tried looking on-line for the explanation but I drew blanks. I wish to find out what it is that makes the adjustment wander. I'm baffled that I have to adjust finer and the go coarse in two shots.

Can someone please explain in 'six-year-old-child' terms how and why this is and how it happens. I have never had to struggle this much with a grinder before.

HB wrote:For what it's worth, when I test grinders, I usually run ~2 pounds of stale coffee through for small grinders and at least 5 pounds for large commercial grinders. It's not a tragic mistake if you skip the burr seasoning, just a little grind setting inconsistency.

New burrs go through a break-in period where you may be chasing your tail to get the right grind for your shot a bit. Once you've seasoned the burrs a bit, they settle down and are more consistent. Sorry I don't have a more scientific explanation, this is just based on strong anecdotal evidence.

Adjust your grinder to the finest setting (above zero) and get some kilos through it.
Conical burrs need much more seasoning than flat burrs.

Here is Scott Rao's take on seasoning burrs, starting at 0.20min

https://www.youtube.com/watch?v=tiqjf8- ... 63nIJCTpCQ

Thank you for the link Terranova. It still beats me how burrs that have not been adjusted can give such a huge variance - Turkish to drip, back to back. I guess this is the grinder's way of telling me to start paying more attention to new additions in my arsenal.

Been searching all over the Internet for a fellow Zenith owner who had anything to share with regards to seasoning.

I can tell you from a lot of careful analysis and recording that luscious shots I was pulling at 2.75 setting in its first week, I now need to pull at 1.5.

So there's definitely been a huge change. Definitely too big to attribute simply to 'no two roasts of the same blend behave the same way'. This is Square Mile I'm using. The benefit of consistency had to be attributed. It was the mythical 'seasoning' I never really believed in.

Another practice I've recently given up on is timing my shots. I weigh my dose, I weigh my yield, and I dial-in based on flavour. What tasted great at 30 seconds has actually ended up going to 41 seconds now. And you can 'see' it in the extraction. The pours started becoming too creamy from the start.