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How to experiment?

With so many coffee courses being offered both on and offline, many people are starting to blindly regurgitate what others say.

The specialty coffee industry was started by people that challenged the traditional standard of what coffee was and how it was served.

Let us never stray from that.

To promote a more sustainable coffee chain, we need all of the links to be strong. This requires the baristas, brewers, roasters to continually experiment, push the boundaries, and master their craft.

So in this article I want to talk about doing experiments, and give you 2 examples of an experiment I recently did.

As many of you may have learned in middle school science class, there is something called the “scientific method.”

It is as follows: observation, question, research, hypothesis, experiment, analysis, conclusion.



Many brewers have different methods of the bloom, yet they all swear their way is the best.

Stir? Pour slowly? Pour fast? Which ratio is best? Or a 1:2 or even a 1:3?


What would the effect of changing the bloom temperature and ratio be?

How does changing bloom temperature or ratio affect the overall cup?


If I use a lower temperature bloom, then the acidity will be lower.

If I use a higher ratio bloom, then the acidity will be brighter.


It is important to know how to isolate variables. If you change too many variables, you will be shooting in the dark. You won’t know the difference between coincidence, correlation or causation. For example, when I look at one variable, I keep ALL of the other variables constant: dose, ratio, temperature, height, spins, time, etc.

With science, the more objective the better. However, in coffee, TDS and extraction numbers don’t necessarily mean the coffee is delicious. So I will be using TDS, extraction percent, and sensory analysis to compare and contrast the cups.

In any experiment, you need to have all of the variables written down. Be clear which variables you are changing, and which variables you are not changing.

Make sure to write EVERYTHING down: the more information you write down, the better. This will help with analysis, repeatability, and accuracy.


Experiment 1.

In my first experiment I altered the bloom temperature, but kept all other variables the same:

Bloom time, brew temp, dose, ratio, time, grind size.

For this experiment I invited Q grader instructor Marty Pollack, and Sudanese Q Grader Ahmed Tahmer to taste with me and see.


The coffee for this experiment was Torch’s Myanmar Wa State, washed processed coffee. This coffee is a very balanced cup of coffee. It has comfortable acidity, medium sweetness, smooth body, and a clean finish.


Experiment 2.

This experiment was to see how bloom ratio affects the overall cup. I altered the bloom ratio, but kept all other variables the same:

Bloom time, temp, dose, brew ratio, time, grind size.


For this experiment I invited Q grader instructor Marty Pollack to taste with me and see.

The coffee for this experiment was Torch’s Yunnan Zebra Manor Natural processed coffee.

This coffee is a crazy fermented natural. Comfortable acidity, intense sweetness, thick and smooth body, with interesting flavor notes.



At this stage, you just point out trends. Try to get all of the trends out and on paper. This will help you draw conclusions. It is important to not talk about “why” just yet. Just clearly point out “what happened.”


After you identify all of the trends, then take a step back and ask “is there a trend among the trends? Is this trend supported by background research? Why would this be the case?”

My analysis:

Changing the bloom for the clever dripper does not have much impact.

For the v60, the bloom had more of an impact. The TDS and extraction changed, the acidity and balance of the cup were different.

Extracting more out in the beginning, i.e., higher bloom temp and bigger ratio, led to more acidic cups of coffee. Anecdotally, cold brew has low acidity. I have talked with several people that brew cold brew, and they use low temperature water at a long time. The higher temperature led to more harsh acidic tones.


Combining your background research, experiment and analysis, what can be learned?


My conclusion:

There are not any hard and fast conclusions that can be drawn. If I wanted to be able to make some hard lines that would be true across several coffees and different brew methods, I would have to repeatedly brew the same coffee over and over to get accurate results. Then I would have to brew with several coffees of different origins, densities, varietals, processing methods, roast dates, etc.

However, what I noticed about increasing extraction in the beginning goes with the background research I have done: acids dissolve quicker, but require higher temperature. This is why cold brew made with low temperature is lacking in acidity.

Under-extracted coffee also has a very harsh acidity with an ‘empty’ aftertaste as the sugars have not dissolved fully into the cup yet.

I never want to blindly follow anyone. I want to know why things are the way that they are. Even if someone else has done an experiment and can objectively prove an answer, it is still important to do it yourself. You can know something to be true because someone else said it, or you can know it to be true because you yourself have experienced it.

Experience leads to wisdom.


Future development:

In my opinion this is an important step that is not always highlighted. Sometimes in your quest for an answer, you stumble upon a lot more things that you are curious about. You don’t want to constantly chase rabbit trails, but you need to identify these other questions, so you can put time aside later to find the answers.

This is an important step in creating a feedback loop: what went well, what would you change, what other questions do you have?

My Future Development:

Does the quality of coffee matter? Both coffees I used are 84+ coffees. If I were to use 78-82 coffees, how would the extraction be changed?


In my second experiment I used a grinder that I am not use to using and my brews were all under extracted. Using a grinder I am comfortable with would have led to good extraction. Would a different extraction highlight different aspects of the cup that have been changed?



The world is a beautiful and complex place. We will never know everything, but it is fun to work and uncover some of the mysteries along the way.

The more I learn, the more I realize that I don’t know very much. This practice of being constantly humbled by the complexity of nature is both frustrating and exciting.

Keep on.

Push the boundaries. Master your craft. Honor the work of the farmers.