Mineral Tetris: Simon Gautherin’s Puzzle of Coffee Water

Born and raised in Paris, France, Simon Gautherin go to Australia in 2016 to pursue a master's degree in Business and Management.

His professional journey in specialty coffee encompasses roles in consultancy, research, and education. 

HUDES | Worldwide Digital Magazine for Manual Coffee Brewers

Currently, he serves as the Coffee Education Manager at Zest Specialty Coffee Roasters and is the co-founder of APAX LAB, a company specializing in water mineral concentrates designed to enhance coffee flavors.

Simon Gautherin | photo by APAX LAB doc.

Water makes up about 98% of a cup of coffee, yet for a long time, it was treated as just another brewing variable—something secondary to beans, grind size, or brew ratios. 

But what if water was more than just a medium for extraction? What if, like seasoning in cooking, it could be adjusted to fine-tune flavors with incredible precision?

That’s exactly what Simon Gautherin has been doing. Known among coffee professionals as “the guy who can fix coffee with water,” he has helped numerous competitors optimize their brews, many of whom have gone on to win national and international coffee brewer championships. 

Over the past two seasons of Brewers Cup, AeroPress, Barista, and other competitions. 

102 national champions and two world champions have claimed their titles using Apax Lab’s product. 

His expertise in water chemistry eventually led him to develop APAX LAB, a brand that provides mineral concentrates designed to bring out the best in every coffee.

This time, Hudes magazine had the opportunity to chat with Simon Gautherin about his approach to water for coffee brewing and the reputation that earned him his unique nickname.

TUNING WATER - Mineral impact on coffee flavors.

HUDES: Simon, your journey into coffee science is fascinating. What initially sparked your interest in the chemistry of water and its impact on coffee flavors?

Simon Gautherin: I've been brewing coffee daily since I was 18 and quickly noticed that even with the same beans, variations in brewing variables could lead to drastically different flavors. 

This realization ignited an obsessive quest to understand how different factors influence the final cup profile. Water stood out immediately. 

I began creating my own water from scratch, experimenting with various minerals, and studying their impact on coffee flavors. 

What fascinated me most was the predictability and replicability of these effects across different coffee types, roast levels, and brewing methods. It gave me a sense of control over flavor, much like adjusting seasoning in cooking. Over time, I came to see water not just as a brewing variable but as an ingredient in itself, deserving equal attention and precision.

HUDES: Developing mineral concentrates sounds challenging. What were the biggest hurdles in formulating the mineral profiles for APAX LAB?

Simon Gautherin: APAX LAB emerged from my reputation for crafting excellent water for coffee competitions. Over the years, I assisted numerous competitors in fine-tuning their water to optimize brews, earning the nickname "the guy who can fix coffee with water." 

Initially, I received frequent requests to ship water, which wasn't practical. Moreover, I don't believe there's a one-size-fits-all mineral profile; each coffee benefits from a tailored composition. The solution was to condense the water I made for competitions into highly concentrated vials.

Scaling up production presented challenges, but partnering with a Melbourne lab, we developed an innovative manufacturing process ensuring consistency and shelf stability. 

Chemically, a significant hurdle was managing ions that tend to bind and precipitate in concentrated environments. We had to carefully select which ions could be combined and which needed separation to maintain usability.

HUDES: Educating consumers about water quality's role in brewing can be complex. How do you approach this with coffee enthusiasts?

Simon Gautherin: By the time we launched, many coffee professionals already recognized the importance of water and minerals in brewing, thanks in part to pioneers like Third Wave Water. However, water remains a vast and complex subject. 

At APAX LAB, we aim to simplify this complexity. Instead of delving into technical jargon like "General Hardness" or "pH levels," we focus on how different minerals influence the final cup. 

This approach ensures even a six-year-old could use our products. For instance, if you desire more acidity, use TONIK; for more sweetness, add JAMM. We also avoid labeling water as simply "good" or "bad." Mineral content exists on a spectrum, and understanding that opens up endless possibilities for optimizing flavor.

HUDES: Have there been any memorable collaborations that influenced APAX LAB's development?

Simon Gautherin: One of the most memorable collaborations was with Carlos Escobar in 2019. Competing in the Brewers Cup for the fourth time without prior national advancement, we worked together to fine-tune his competition water. 

That year, he not only won the entire competition but also placed fourth in the World Championship. This was a significant breakthrough, as most improvements came from adjusting the mineral composition. 

Other key collaborations include Rasmus Madsen, Young Baek, and Jerome Rosler, who provided invaluable feedback shaping our products. Scientifically, we worked with water experts like Monika Fekete to overcome early technical hurdles.

HUDES: The coffee industry is continually evolving. What trends excite you, and how is APAX LAB adapting?

Simon Gautherin: We're currently developing a solution for cafés that integrates with Reverse Osmosis (RO) systems. While many companies offer excellent filtration systems that strip water of minerals, few have perfected remineralization. That's where APAX comes in. 

We're exploring partnerships to develop the ultimate water solution for espresso machines in cafés, ensuring optimal flavor and consistency.

HUDES: Cultural preferences can shape coffee flavors. How does APAX LAB cater to these diverse tastes?

Simon Gautherin: Specialty coffee consumers generally fall into three flavor preference categories: vibrant and acidic, round and sweet, and elegant and floral. 

From the beginning, we designed our mineral profiles to enhance these attributes. We often get asked which profile is "best" for a given coffee, but the real question is: what do YOU like? 

Personally, I love acidity, so I add TONIK to almost every coffee I make. Interestingly, we've observed regional patterns in preferences: TONIK is popular across Europe, JAMM is favored in North America, the UAE, and Australia, and LYLAC is a superstar in Asia.

HUDES: On a personal note, what's your daily coffee routine?

Simon Gautherin: I almost exclusively drink filter coffee. Every morning, I brew two cups, changing only one variable to observe its effect on the final cup. This process has taught me a great deal about coffee and helps me anticipate how different factors interact. 

I usually start with demineralized water or water at 60-90 ppm, then adjust the minerals directly in the cup depending on what the coffee needs. When making coffee for someone else, I go full precision mode—but when it's just for me, I keep it casual, cowboy-style.

HUDES: For those aspiring to delve into coffee science, what guidance would you offer?

Simon Gautherin: "Focus on the what, not the why." Too often, people obsess over why things happen a certain way. For example, why does magnesium highlight fruity and acidic notes in coffee? 

To be honest, I don't have the answer—and I don't mind. What I do know is what happens when you introduce magnesium to coffee. 

Understanding the dynamics of variables and predicting outcomes is more valuable than understanding the underlying reasons. My advice? Experiment for yourself. Form your own opinions. Keep things simple, trust your taste buds, and let them guide you. (hudes)