Slow feeding grinder for pour over

MWJB

After a suggestion that slow feeding beans can ‘transform your grinder’, I thought I’d give it a go. My 2 candidates were my Niche Zero and Wilfa flat burr grinder. All brews were 13.8g to 200g with a Switch used as a pour over with Drip Assist.

Niche Zero fitted with NFC disk - Slow feeding with the lid open makes this a pop-corning nightmare with partial & whole beans occasionally fired out of the grinder. I was therefore heavily disinclined to continue with doing this with the Niche after a test brew & sifting samples. Compared to the regular ground dose, the slow fed brew extracted a couple of % higher in EY, but the flavour was not improved, being dry with a powdery mouth feel. It wasn’t over-extracted, brews with other grinders at higher EY’s were still tasting OK.

Wilfa flat burr grinder - This was fine with slow feeding, no beans/partial beans ejected from the grinder. Just needed to occasionally restart the grinder after auto stopping mid grind. Previously, I had already found that the Wilfa has a slightly wider distribution than my other frequently used grinders and was interested as to what benefits I could perceive. Again, brews were drier, more pronounce mouthfeel and despite trying 4 brews covering a range of extractions, I couldn’t get any of the slow fed brews to show improvement over regular dosed brews.

Sifting samples with both grinders didn’t suggest that smaller particles were reduced at all. In both cases the average grind size was pushed a little coarser. For the Niche Zero, the distribution was not any tighter overall. In the case of the Wilfa, slow feeding did reduce the % of larger particles significantly, so whilst the average grind size was larger, the distribution was measurably narrower.

One way you could look at this is that if you set the grind coarser, to shift the average grind size, you normally see a drop in the % of smaller particles, say less than 400Kruve. In effect, a coarser grind without doing this is basically a grind with a higher % of small particles/fines, which seems a strange thing to want to have.

I’m not discounting that there may be a grinder that can benefit from doing this, I just haven’t seen it with these.

LMSC

Interesting exercise. I can grind a normal dose and a slow feed, sift with 400 Kruve at the bottom
and the max sieve (1000) to see the difference.

In either case, the distribution will be skewed as the bulk of the coffee powder will still stay above 1000 Kruve.

But, I can check what the % of fines under 400 Kruve is, probably for a few coffee bags in the case of 9% and 12%. This will be the Duo.

Please let me know if this would interest you.

MWJB

LMSC Sure, the more data the better, if you have time. Thanks.

1000Kruve will probably be around the 50% mark (+/-10%)?

LMSC

MWJB 1000 is what I have. I should get a set of higher sieve pack!

MWJB

LMSC 1000 would work well enough to see if the average size moves and whether the 400 does too.

LMSC

Managed to sift and compare normal versus slow feed grinds of one coffee on the Duo. The grind reference points on the zeroed filter burrs set on the Duo were #32 (12%) and #45 (9%). I haven’t brewed them yet. I will post my taste observations.

Ground 12g of coffee for each sifting. The sieves were 400 Kruve and 1000 Kruve. The percentage of fines, say, under 400 Kruve and between 400 Kruve and 1000 Kruve have gone down in the case of slower fed beans on the Duo suggesting the slower feed is making the grind size coarser overall.

This is just 1 coffee. I will try to repeat this for a few more coffee to get an average readings between two feeds over time. :-)

LMSC

The slow feed brew of 12% 400 Kruve (12g, 180g water, 5 × 36g x 40s) was not good. Flavours were muddled and had a harsher taste. It wasn’t a smooth coffee. I would peg the score at 5/9.