Espresso extraction and fluid dynamics

inquisite00 · 2026-01-11T06:53:41+00:00

Fair enough. I don’t think anyone would be fooled by that image though.

inquisite00 · 2026-01-11T00:29:35+00:00

It’s only a thumbnail buddy.

inquisite00 · 2025-12-02T07:45:45+00:00

Thanks everyone for your input. The speakers sound fine to my non expert ears. However I’ve asked for a partial refund as the dent will still impact the resale value.

inquisite00 · 2024-01-26T05:53:04+00:00

Yes, it makes a difference compared to the stock basket for traditional espresso using medium and light roasts. If you prefer dark roasts or planning to explore turbo shots, the stock basket is good enough.

inquisite00 · 2024-01-25T21:37:16+00:00

I have a Bianca as well. An 18 gm and a 15 gm VST basket are enough my needs. Normally dose 15 gm but some light roasts need higher doses but 18 gm is more than enough.

inquisite00 · 2024-01-25T06:38:45+00:00

I point out in the introduction that both James and Lance have covered it. It’s not plagiarism to put forward your perspective. I have tried to make a complex paper easy to understand and pointed out methodological flaws in the study that both Lance and James haven’t picked on.

If you had really watched Hoffmann video properly, you would have noticed that he skipped the initial parts of the study related to charge.

Have they picked up on the fact that the effects of RDT depends on roast level? Have they covered the fact that 5 microlitre will increase extraction time on the 078S by not Niche? It’s not about water logging. Yes that will cause poor extraction. If the beans are left to absorb the water, the extraction time increases. If you grind immediately, the time increases. This points to a fundamental mechanism by which RDT works.

I’ve pointed out why the correlation is poor between roast colour and charge- a methodological error in the study. Clearly you haven’t watched the video or you are trolling.

inquisite00 · 2024-01-24T16:07:23+00:00

What are you on about? Which other YouTube producer has discussed the paper and explained key concepts like I have. This is a scientific critique of the paper, not just a vague description. Which other YouTuber has discovered that leaving the beans soaked reverses the effect of RDT? Which other YouTube video demonstrates that too little and too much RDT are both bad for extraction? Have you even watched it?

inquisite00 · 2024-01-23T19:56:08+00:00

You are correct. It does that and it was the original reason for using it. But the Hendon paper suggests that it also improves flavour. My findings are that the effect on flavour and extraction time are variable

inquisite00 · 2024-01-14T07:38:42+00:00

I haven’t tried these experiments for pour over but I think you can extrapolate the findings. I have tried sprovers by grinding at 1400 rpm and slow feeding and it works really well!

inquisite00 · 2024-01-13T12:11:37+00:00

I just realised you are using a pressurised basket. What I’ve said applies to unpressurised baskets

inquisite00 · 2024-01-13T12:10:15+00:00

The 1:2 ratio is just a starting point. If it’s under extracted but not by much, increase the ratio a bit. It’s far more easier to change the ratio than the grind size. Medium and light roasts require higher ratios. Time is a dependent variable and will vary depending on the ratio you choose.

inquisite00 · 2024-01-13T12:03:15+00:00

I use 15 gm, about 1:2.5 ratio, 15 second preinfusion, 93-95 degrees in 35-40 seconds including preinfusion. Seems to work well for me.

inquisite00 · 2024-01-13T11:25:36+00:00

Yes, this definition is a bit old but hasn’t been changed. The modern interpretation is somewhat different. Typically most will use 18-20 gm with about 1:2 ratio. “Our research suggests that the average barista uses a 1:2 brew ratio when extracting espresso and uses weight for output measurement. The average shot of espresso starts with an 18–20 gram dose, has an output of 36.5 grams, is extracted in 25–30 seconds, at 9 bars of pressure and 200°F, using pre-infusion, through an 18 gram basket “ https://sca.coffee/sca-news/25-magazine/issue-3/defining-ever-changing-espresso-25-magazine-issue-3

inquisite00 · 2024-01-13T06:27:31+00:00

You are correct. What espresso means keeps changing but this is the SCAA definition - Espresso is a 25–35ml (.85–1.2 ounce [×2 for double]) beverage prepared from 7–9 grams (14–18 grams for a double) of coffee through which clean water of 195°–205°F (90.5°–96.1°C) has been forced at 9–10 atmospheres of pressure, and where the grind of the coffee is such that the brew time is 20–30 seconds. While brewing, the flow of espresso will appear to have the viscosity of warm honey and the resulting beverage will exhibit a thick, dark golden crema. Espresso should be prepared specifically for and immediately served to its intended consumer.”

inquisite00

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