"Slow grinding" - Lance is back with another interesting hack

Beginner and pro baristas share tips and tricks for making espresso.
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#1: Post by sympa »

I'm not sure I buy his explanation for why the results are so different, but there is a striking difference in terms of how the grinders perform when you introduce your beans into the hopper little-by-little. Namely, the grounds turn out much coarser (than the standard method of dumping all 18g in at once). Lance claims greater grind uniformity and less fines as well. But one difference is clear: since the grounds are much coarser, the shots are way faster.

Three questions immediately came to mind:

(1) does this technique move us too close to the zero point on our grinders to effectively dial in shots?
(2) what are the results in the cup?
(3) how repeatable is slow grinding?

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#2: Post by erik82 »

This isn't something new and that some of us have been doing for years. Yes you need to go finer and with unimodal burrs you're already near chirp. That leaves us with less room to work with but still enough if you own a good grinder.

In terms of consistency it's more consistent as you know all beans will be ground without any backpressure from other beans also in there. Dumping everything in gives less control and the first part will be ground different than the second part. See it as the first part being ground like a hopper grinder and the second part like slow feeding.

sympa (original poster)
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#3: Post by sympa (original poster) »

I take your word for it, however, I've been reading up on/making espresso for ~3 years now and this is the first time I've seen it mentioned. At the very least, it does not seem to be a widespread practice. I guess my follow-up question is: if it has such effects, why isn't everyone doing it? Especially curious since we espresso fanatics are willing to do all sorts of inconvenient things in the name of chasing god shots.

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#4: Post by HH »

Yes this has been known for a while. It's one reason why hopper-based grinders are not usually good at single dosing, they are designed to have a consistent back pressure from the weight of beans in the hopper.

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#5: Post by erik82 »

There are a lot of posts about slow feeding the last years so you probably missed them. In almost every SD grinder topic people are talking about it. There's also been whole topics about it to but they are I think about 3 years old already. It's pretty widespread information.

There's also a lot of people not doing RDT and WDT so that's also the reason why people don't slow feed. Not everyone wants to do all kind of tricks. And if you have a lesser grinder and unimodal burrs you can be limited by the grinders so than it's not possible. Lots of reasons to think of.

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#6: Post by Jonk »

sympa wrote:(1) does this technique move us too close to the zero point on our grinders to effectively dial in shots?
In some cases yes. But you might be able to just leave the grinder set basically at chirp and work with shot parameters instead. For example with your Robot you can up the dose to 25g or something extreme like that, or just accept a fast shot.
sympa wrote:(2) what are the results in the cup?
I think many of us are just too lazy to really feed one bean at a time :lol: not that you have to do it that slow, but then consistency starts to become an issue. Anyway, I haven't done enough trials for espresso to say much about flavor there, but for filter coffee it can help a lot. See for example Niche Zero - Unimodal Grinding Technique

In the case of the Niche Zero, while it does give a lot better results, I'm at least confident to say that there's more improvement to be gained from just switching to a more unimodal grinder.
sympa wrote:(3) how repeatable is slow grinding?
Depends on how repeatable you are :)
I think we need some contraption to make it convenient at least. For your Mignon, have a look at Regrind technique for light roast espresso - sweeter, less grassy & earthy. Fewer fines?

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#7: Post by mgrayson »

Clearly, the solution is to have enough grinders that you can place one bean in each. That way it's fast AND consistent. :lol:
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#8: Post by coyote-1 »

1. No, at least not on my grinder (flat burr 60mm titanium, espresso oriented)
2. Consistently good.
3. Very repeatable.

I do not feed one bean at a time. My hopper has a "trap door" to allow you to remove the hopper without spilling beans everywhere - but I repurposed it to a slow feed. Likewise I added a bellow, so my hopper functions as a single shot grinder.

It has a feed auger that also apparently functions as a pre-break. So I just put one serving of beans in the hopper, then use the sliding trap door to slow feed them. When done I use the bellow as everyone else does, to blow out the remaining grinds.

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#9: Post by njtnjt »

I've been slow feeding for years with a motorized HG1. The improvement in taste and consistency is well worth the extra time it takes to dribble the beans in. Since trying it the first time I never just dump the beans in.

It's an easy experiment to try. Just know you will need to adjust finer, (quite a bit on the HG series), when you slow feed to get your extraction times correct. The results in the cup speak for themselves. Best wishes!

God wants us to walk but the devil sends a limo.

LMWDP #414

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#10: Post by erik82 »

Also a thing to consider is burr size. The idea is that beans don't get any backpressure. Feeding beans one by one may be good for 64mm as the grinding area isn't that big but you could feed 3 times as fast with say 98mm to get the same effect. With 120mm you might be able to just dump everything in and still have no backpressure.