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Dialing in our pour over coffee brewing variables (Mark I)

It’s been about a month since my timer scale arrived, marking the start of my journey down the pour over coffee rabbit hole. Using single-origin Guatemala beans from Mt Whitney Coffee Roasters, I’ve been making our morning V60 brew by adjusting three variables: (i) filter material, (ii) coffee/water ratio, (iii) grind size and keeping track of our individual tasting scores.

I’ve been winging it when it comes to my pouring technique and generally just make sure that I bloom the grounds first, and then pulse pour until I get around 450ml of coffee, just enough for me and The Wife.

But I wanted to maintain the same pouring technique while I changed the other three variables, and after some Googling, I stumbled on the Tetsu 4-6 technique used by Tetsu Kasuya to win the 2016 World Brewers Cup.

In his own words:

“Now, today. I would like to show you the best brew cup by using the 4-6 method. The 4-6 method begins by dividing the total water into 40% and 60%. You pour the first 40% in two pours, and then decide how many pours you want to make for the last 60%. The first 2 pours decide the balance of the acidity and sweetness. The remaining number of pours will decide the strength of the coffee. That’s it. It’s so simple, isn’t it?”

Or even better, the man himself, in action:

Given that I was using different ratios of coffee to water, I adjusted the amount of water based on the amount of coffee. After using my timer scale for a week, I realised that my DeLonghi KG89 electric burr grinder was grinding widely inconsistent amounts of coffee from the hopper.

In the past, simply by eye-balling it, I could sort of tell that the amounts weren’t always consistent. Now, using the timer scale, and staying at the 4 click (3.5 cup) grinder setting, I could clearly see that the grounds were coming in anywhere from 26.8gm to 31.2gm.

The range of about 15% was wide but I was able to adjust the water weight to match each specific coffee/water ratio. It meant that I needed a calculator to back-out the water weight for each pour though, which made the process a bit fussy i.e.

  1. Weigh the actual coffee grounds produced.
  2. Calculate the total water weight needed, based on chosen coffee/water ratio.
  3. Back out 40% for first two pours, with the first pour using 2x coffee weight to bloom in first 45 seconds and finish second pour within next 45 seconds.
  4. Divide the remaining 60% into three equal pours, with each starting after the previous pour had more or less drained through.

After repeating this over 18 days, here’s what my taste comparison chart looked like, on a subjective 1-10 scale.

And here’s the same chart for The Wife’s scores.

The first, and most important, observation was that we had the same favourite cup, made using the Hario 02 tabbed paper filter with a coffee/water ratio of 1:17 and grind setting at 06 (medium-fine).

This was quite surprising to me as I had initially thought that our favourites would be very different, given that she prefers stronger tasting brews and I lean more towards lighter and cleaner tasting profiles.

By averaging the scores across both our charts, it seems we prefer:

  • Paper filters (6.5) over our re-usable metal one (5.9)
  • Coffee/water ratio of 1:17 (6.9) vs 1:16 (6.0) or 1:15 (5.7)
  • Medium-coarse 10 grind setting (6.7) vs medium 08 (5.9) or medium-fine 06 (6.0), although it should be noted that our favourite cup used the medium-fine 06 setting.

Moving forward, as we try other coffee beans, I’ll use these as our baseline and starting dialing in the variables from there.

Throughout this entire process, there were two things that were bothering me though.

The first was the variability in the amount of grounds produced by our DeLonghi grinder. In its defense, it’s an entry-level S$90 burr grinder and has been remarkably reliable over the years. However, not being able to generate a consistent weight means that I could potentially get 75ml less coffee in the morning.

And as we coffee addicts know, having less coffee in the morning is not a good thing, especially when it comes as a surprise. So, I think it’s time for me to consider getting a good manual grinder and I’m currently leaning towards the 1Zpresso JX which is going for US$129 on their online store.

The second was the fussiness of the pour technique. I get that the Tetsu 4-6 approach gives me the flexibility to adjust the strength and flavour profile by tweaking how I pour (e.g. two pours vs three in the 60% phase etc), but having a calculator beside me seemed a bit excessive and I can’t do math in my head before I’ve had coffee.

So, I’m going to try Hoffman’s V60 technique next which seems simpler and less fiddly. I’ll keep the Tetsu 4-6 in my back pocket and take it out in the future, when I actually need more flexibility.

I knew that I’d be going down a rabbit hole when I got my timer scale, and it’s starting to look like it’s going to be a long and winding one. But hey! At least we’ll get to have better and better tasting coffee. And that is always a good thing.

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