A grinder dialogue

Matin wrote me and asked:

I recently stumbled upon a video of your Compak grinder paired with the small dosing funnel. I was wondering if you can share your single-dosing experience with your grinder? Is grind quality affected when you single dose?

My reply:
Single dosing works best for me in a really big grinder like the R120 where the size of the burrs and the speed make it near impossible for beans to pop and bounce around during grinding.

With the small dosing funnel I do not single dose but I do ‘small dose’, keeping the tiny hopper filled so there is some weight / mass of beans resting on the beans that are being caught between the burrs and that way the grinds come out very nicely, enabling a good extraction.

With single dosing on these ‘not huge’ grinders, the extraction is a bit more difficult to get right, in my experience.

Even with the R120 there is a rare bean bouncing around but no bad effect on the grinds / extraction.


Matin:

I've actually come across a product that introduces a weight on top of the beans.
 How difficult would it be to dial-in these 'not huge' grinders? I am torn between a Compak E5 (flat burr) and Compak E10 (conical burr).
 Have you ever come across any other grinders that are capable of single-dosing?

My reply:
Weights on top of beans have been tried in many versions, but the weight can never push all the way like beans can so it’s always a compromise.

The EK43 by Mahlkönig does dingle dosing well too, but that grinder sometimes need minute burr aligning which can be a nuisance.

Is there an urgent reason for you to do single dosing? Why would you?

I do single dosing on the R120 after every roast so I can measure the roast color but I don’t use those grinds to make coffee (too fresh) and I use the R120 if I want to figure out what the most optimal grind / shot / taste is for a roast, allowing me to try different grind settings. The procedure uses up a lot of beans but since I roast enough volume myself that’s not a problem for me.

Dialing in the E5 is very easy, straightforward.

I like the E5 - E6 - E8 line, but never tried the E10.

http://kostverlorenvaart.blogspot.nl/2017/06/the-four-daltons.html

Matin:

I have been manual brewing at home for a few years now, and I'm now considering crossing into the espresso realm. As such, I've grown accustomed to the workflow associated with filter coffee preparation i.e. preheat brewing vessel, weigh out beans, grind beans, brew coffee. I only grind what I need and there is no need to alter grind settings until I move on to a different bag of coffee.
I figured I could replicate the same workflow for espresso extraction. Primary reason for single dosing is to avoid wastage of beans, this is of paramount importance. These are the types of questions that comes to mind when I think of a fully-loaded hopper:
Given that the weight on the beans will decrease as the week progresses, does this require a more frequent dial-in process in the mornings;
Freshness of the beans left in the hopper; and
The need to purge grind when changing grind settings.
Where I'm from, I have to source beans from neighbouring countries, having to depend on the occasional business trip or friends travelling to secure beans to last me a month. Unless you can convince me otherwise, I think single dosing is the way to go.

Me:
In the ‘normal’ hoppers I let the level of beans go down until they are finished. I could stack another roast on top but I want to know for sure when one batch is finished and another is in the hopper so I will be able to note the difference and write down on the roast profile how I liked these beans of that roast over time.

That means accepting that the last bit of the grinds may be somewhat more messy in the extraction. I won’t worry about it since I expect it.

As long as there are a few handfuls of beans on top, it’s all fine, no problem and there is no ‘heavy weight’ needed. The popping of beans is not an explosive force to press down on. Not really spectacular.

At the start of the day I grind away about 2 seconds of beans before preparing my dose in the basket, so I get fresh grinds, ensuring that any half-crushed beans or grinds in between the burrs from the day before are out. A fiend of mine actually uses that first dose of the day as he feels the mildness of the extraction works very well for him in the early morning. So you can decide to ‘waste’ about 10g of beans or use them on purpose.

In the R120 I always throw in a small handful of beans and grind them away before grinding what I will use for measurement or espresso. So the R120 is not there to prevent ‘waste’. I want to make sure that what I measure is really the recent roast and not in part whatever previous grinds might be hanging in there. There is hardly any ‘retention’ but when working in a lab environment, taking accurate measurements, I feel it’s worth while to make extra sure the grinds are correct. Also when I experiment to find an ‘ideal’ dose / grind setting for espresso on the R120, I throw in a handful of beans in between every grind adjustment and grind, so I use up a lot of beans but the aim is to find the best shot real fast, not save beans.

I enjoy noticing the slow development of taste. Beans roasted need a week of rest, then they can be thrown into the hopper. They slowly age there and over the week or weeks I like discovering how the taste can get richer, more subtle after the ‘sharp’ freshness subsides, and if I have 1kg in the hopper, I can monitor the process for weeks. Sometimes towards the end the bean is absolutely fabulous, subtle, tasteful, before it ‘falls asleep’ and its time is over.

No need to ‘keep fresh’ the bean bag in a ‘hidden’ place. First of all, the ageing of the beans cannot be stopped anyway and complicating it by single dosing does not make life easier. Fussing around with ‘frozen’ beans makes it even worse, with condensation and the sudden temperature shock the beans will go through.

Matin:

Thanks for presenting a different perspective, offering a glimpse into your daily workflow. Do you dial-in your coffee daily with the full hopper methodology?
I now realise how tedious single dosing will be, I should just enjoy the ride and learn as I go. This will certainly open up more grinder choices for me, although Compak E5 is at the top of my list...

Me:
Mostly I leave the grinder as it is. My roasts all aim for about the same type of roast depth ao hardly any correction needs to be made. Sometimes when I have roasted lighter than planned, I need to grind a little finer and dose a little more for that batch.

So adjustments are made rarely, and certainly not every day.

A timer on the grinder also compensates for any small changes. If for instance the timer is making 18g of grinds in 5 seconds, and for some reason (temperature change in the room) the burrs are a little wider apart, then the grinds are a tiny bit more coarse which is compensated because in that case the grinder produces a little more grinds in the same 5 seconds. So the flow which would otherwise be faster with 18g of coarser grinds is about the same because I get (for example) nearly 19g of grinds instead.

If one buys 250g from one roast and then 250g of another, from another roaster even, then one always need to be tweaking and dialing in. So it's an advantage to get more beans of one specific roast and make that stock last for a few weeks.

Thank you Matin!!