Post By gonzob
Hand grinder as roasting aid
With great fear of putting a cat among the pigeons, I'm going to put forward the hypothesis that a hand grinder (I'm using a Lido) is a great tool for fine turning 'ideal' roast depth and profile, as the changes in turn resistance are easily felt in a hand grinder, and that by adjusting the profile to achieve a consistent 'feel', you are also roasting to an ideal baseline for any given bean and roast depth…
What leads me to this spot is that I've found that in many beans - when I have roasted via trial and error to the best flavour profile for my taste - there is generally no grind adjustment required on the hand grinder. But when I muff it, I have to make large changes.
For example, the Harrar Longberry. Roasted with a long profile, the bean is super soft (think baked) and responds in the grinder like I've put baked beans in there rather than coffee beans - no resistance at all - easy grinding. But then it chokes up the machine. So therefore you make massive adjustments to grind.
But … with my latest batch of Harrar, roasted with a faster profile, it 'feels' like every other bean, pours like all the others - and tastes great!
On the other end - a bean like a brasil, roasted too fast, is really hard going in the grinder and tastes a little lifeless. Stretch it out, feels good in the grinder, pours well, and has the great sweets cocoa flavours we'd expect.
So … maybe there an ideal, consistent espresso roasted bean development level, achieved by varying profile dependent on bean and origin, that will work for every bean?
Just a few thoughts…
PS I do know this won't work quite the same for filter roasts - but I wonder if they will also all be harder work to grind at the same roast depth?
So... if you were able to turn the grinder at a fixed RPM and measure the torque you were applying... you could put some numbers to this??
I feel a new machine design project coming on!
Reckon that'd be about right
I think it can only give you a good indication of the roast level. I don't think you'll see any differences between two roast profiles that were dropped at the same temperature but one was stalled and one had a proper development. I might be wrong though, looking forward to hear more about your experiements with this.
Bit like in the mining industry we have crushers.
Just by looking at the load "current drawn by motor" it gives you a clear indication how hard the grinder is working. If the grind is too coarse load drops off.
As you pull in the gap between mantle and concaves "burrs" load increases producing fine grind.
Harder material (beans) will pull harder loads. But this is something that you will learn. Certain beans will require different loads to archive same grind.
Hmmm PID grinder!
Certainly would assist dailing in grinders every morning in commercial use?
Possibly reducing coffee wasted.
I can see a little project going on with my K8.
Few things need to account for. Wearing burrs and weight in the hopper.
Very interesting thread, and especially so for me at present. I'm currently using a ROK hand grinder fitted with Baratza burrs. With the original burrs it was useless for espresso, but now it's working very well. A couple of weeks ago I tried a couple of different beans from FiveSenses in WA. They were by far the hardest and densest beans I have ever encountered. In the electric grinder I could hear the motor struggling, and in the ROK I could feel much greater resistance. Much more effort was needed for both of them than for my own roast beans. One was a Brazillian and the other from Guatemala. Both looked quite light in colour, but did not taste as light as they looked. ( Sorry, but my uneducated palate can't be more specific than that ).
Like Mal, I have noticed some minor variation in resistance between beans while grinding them by hand, but I put it down to the origin of the beans rather than the profile or depth of the roast. But the 5Senses beans were radically different to any of mine, and that puzzled me. Then Mal comes up with these observations about roast profiles as well as bean origin and now I'm really curious. I will have to try some roasts with the same beans, with different profiles and depths. I have a couple of greens in my stash that I'm not really keen on, so I won't have to sacrifice any of my favourites. Who knows ?, I might even find a profile that works for them.
Does anyone here know what sort of profile(s) FiveSenses use for their roasts, or is it a closely guarded secret ?. I had a quick look at their website, but I saw nothing that gave me any clues to their roast method or profiles. Some of their beans are offered with a choice of espresso or filter roast, others as espresso only. The ones I tried were for espresso, but when I first saw them, I checked the labels, because I thought they might have been filter roasts.
Hand grinder as roasting aid
This theory definitely has merit in my mind. Simply doing it by hand with a Lido or similar will only give you a very basic idea without much consistency, but it'll at least be one more small tool to help judge the outcome of a roast.
Some sort of grinder that can measure the torque required to grind beans where every other part of the process is fixed (motor power, RPM, bean weight etc.) could give some consistent and interesting results I'd imagine. An HG One could be a good one to mod as it could be fitted with a moderately powered motor to provide low RPMs.