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Café OS

Real Labs

3D cannot teach taste. Six kitchen experiments — same bean, one variable at a time — and a place to record what you found.

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Each lab changes exactly one variable and keeps everything else constant. When you finish, write down what you tasted in the lab log below. If you can also explain in your own words why it changed, you have really understood the concept.

How to run a real lab

Predict first. Before brewing, write down which cup you expect to be more sour, more bitter or stronger.

Change one variable only. Apart from the item under “Change only”, keep everything the same: same coffee, same dose and water, same technique.

Taste side by side. Let the cups cool to a similar temperature, go back and forth, name the difference first, then decide which you prefer.

Record it, then plan the next step. Write down the result and taste, then pick exactly one variable to change in the next cup.

Records are stored only in this browser on this device. They also appear in the Brew Log; review and export them there or in My Progress.

The six labs

1.Grind Experiment

Chapter 20 · Grind SizeConcepts：Particle Size Distribution, Extraction

Real lab

Grind Experiment

Change only：Three grind settings

Keep constant：Same coffee、Same ratio、Same temperature

Lab log · Grind Experiment

Grind Experiment · Save this cup

Only “Next change” is required (marked *). Record as much of the rest as you like.

Ratio

Fill in dose and water to compute it

This lab changes only: Three grind settings

Taste

Each from 1 (very little) to 5 (a lot); leave blank if you did not notice.

Sweet
Sour
Bitter
Body

Explain the result in your own words. Doing so raises related concepts to “Explained”.

Next change: one variable only

Change one variable at a time: pick the variable, then the direction.

Stored only in this browser on this device. Never uploaded.

Full brew log

2.Ratio Experiment

Chapter 22 · Brew RatioConcepts：Brew Ratio, Strength

Real lab

Ratio Experiment

Change only：Different ratios

Keep constant：Same coffee、Same grind and technique

Lab log · Ratio Experiment

Ratio Experiment · Save this cup

Only “Next change” is required (marked *). Record as much of the rest as you like.

Ratio

Fill in dose and water to compute it

This lab changes only: Different ratios

Taste

Each from 1 (very little) to 5 (a lot); leave blank if you did not notice.

Sweet
Sour
Bitter
Body

Explain the result in your own words. Doing so raises related concepts to “Explained”.

Next change: one variable only

Change one variable at a time: pick the variable, then the direction.

Stored only in this browser on this device. Never uploaded.

Full brew log

3.Temperature Experiment

Chapter 24 · The Five Major Brewing VariablesConcepts：Temperature, Extraction

Real lab

Temperature Experiment

Change only：Two temperatures

Keep constant：Same recipe

Lab log · Temperature Experiment

Temperature Experiment · Save this cup

Only “Next change” is required (marked *). Record as much of the rest as you like.

Ratio

Fill in dose and water to compute it

This lab changes only: Two temperatures

Taste

Each from 1 (very little) to 5 (a lot); leave blank if you did not notice.

Sweet
Sour
Bitter
Body

Explain the result in your own words. Doing so raises related concepts to “Explained”.

Next change: one variable only

Change one variable at a time: pick the variable, then the direction.

Stored only in this browser on this device. Never uploaded.

Full brew log

4.Immersion vs Pour-over

Chapter 25 · Immersion vs PercolationConcepts：Immersion, Percolation

Real lab

Immersion vs Pour-over

Change only：Extraction geometry

Keep constant：Same bean

Lab log · Immersion vs Pour-over

Immersion vs Pour-over · Save this cup

Only “Next change” is required (marked *). Record as much of the rest as you like.

Ratio

Fill in dose and water to compute it

This lab changes only: Extraction geometry

Taste

Each from 1 (very little) to 5 (a lot); leave blank if you did not notice.

Sweet
Sour
Bitter
Body

Explain the result in your own words. Doing so raises related concepts to “Explained”.

Next change: one variable only

Change one variable at a time: pick the variable, then the direction.

Stored only in this browser on this device. Never uploaded.

Full brew log

5.Sensory Triangle

Chapter 35 · How to Taste CoffeeConcepts：Sensory Perception

Real lab

Sensory Triangle

Change only：One of three cups differs

Keep constant：The other two are identical

Lab log · Sensory Triangle

Sensory Triangle · Save this cup

Only “Next change” is required (marked *). Record as much of the rest as you like.

Ratio

Fill in dose and water to compute it

This lab changes only: One of three cups differs

Taste

Each from 1 (very little) to 5 (a lot); leave blank if you did not notice.

Sweet
Sour
Bitter
Body

Explain the result in your own words. Doing so raises related concepts to “Explained”.

Next change: one variable only

Change one variable at a time: pick the variable, then the direction.

Stored only in this browser on this device. Never uploaded.

Full brew log

6.Water Experiment

Chapter 21 · Coffee and WaterConcepts：Brewing Water, Extraction

Real lab

Water Experiment

Change only：Two waters

Keep constant：Same coffee、Same recipe

Lab log · Water Experiment

Water Experiment · Save this cup

Only “Next change” is required (marked *). Record as much of the rest as you like.

Ratio

Fill in dose and water to compute it

This lab changes only: Two waters

Taste

Each from 1 (very little) to 5 (a lot); leave blank if you did not notice.

Sweet
Sour
Bitter
Body

Explain the result in your own words. Doing so raises related concepts to “Explained”.

Next change: one variable only

Change one variable at a time: pick the variable, then the direction.

Stored only in this browser on this device. Never uploaded.

Full brew log

3D Scenes and Real Labs

Each scene answers one question — what idea does it make clearer than text? Each lab changes one variable.

Fix My Coffee

What is wrong with this cup? Name the symptom, check the suspects in order, then change one variable in a controlled experiment.

On this page

How to run a real labThe six labs