Leogant Founder Thomas Hartwig reveals all his expert tips on vitalized water in an exciting interview!
High-quality water is essential for our unpasteurized kombucha. Just like our bodies, a SCOBY quickly notices which water is particularly beneficial. Water for fermentation should always be filtered and free of harmful residues. In our exciting interview with Leogant founder Thomas Hartwig, you'll get many important insights into water and water filtration. We also give you useful tips on how to filter and treat your water at home for kombucha fermentation.
The Path to Leogant's Founding by the Berlin Water Guru
How did you come up with the idea to found Leogant? Please introduce yourself briefly!
I founded Leogant about 12 years ago. The founding was much more than a simple business case; it was a life's work, always with a clear focus on a conscious business with meaning. From the beginning, there was a very clear purpose: to make people feel good with good water. The business model was secondary. I myself am a trained restaurateur and later studied the Asian martial art Kung Fu in China. I always had an affinity for high-quality food and a good sense of my body. Back in Berlin, I continued to focus on nutrition and sports, and ate a vegan diet. With 6 hours of exercise a day, I quickly noticed how much more efficient my body was with high-quality spring water from the organic market. This had such a big impact on my performance and recovery that the topic of water never let me go. In general, I slowly became more and more aware of my body holistically.
It's actually obvious, because our bodies and our Earth consist largely of water. My body changed with high-quality water not only during physical activities and high-performance sports, but I also noticed a positive influence on concentration and body odor. Water is also very interesting on a scientific level. No substance has so many properties, anomalies that science cannot explain. With the founding of Leogant and our water filter systems, I have developed a sustainable and holistic solution to meet the individual needs of people and want to bring the importance of water on our organism more into focus. All this with a sustainable business without compromises.

How does the LEOGANT filter work?
I used to pack the first water filter packages myself in my 20 sqm office. I collected boxes from everywhere to work as sustainably as possible. This sustainability, which wasn't as en vogue then as it is now, is still reflected in our filter systems today. All components of the water filters are existing products. From the very beginning, I scrutinized what the market already offered, took existing systems apart, looked for ways to improve them, and reassembled them as newly combined water filters.
The 2-Phase Filter System
The important underlying approach is a consistent natural approach or natural water refinement. Our 2-phase system filters and – what is special – it vitalizes the water. This means that in the first phase, with the help of activated carbon cartridges, residues of hormones, medicines, pesticides, microplastics, parasites, lead, copper, chlorine, and many other chemical and organic residues are removed. In the second phase of water refinement, vitalization takes place, which turns tap water into living water of spring quality.
What happens to the lime in the water?
The lime content is often viewed very critically. However, lime occurs naturally in water and contributes significantly to its taste. Therefore, we do not remove the lime initially, but rather prepare it so that it is bioavailable for our body and does not accumulate undesirably. Calcium and magnesium are vital minerals for humans. In the end, the hardness of the water is a matter of taste and can, of course, be filtered out if desired.
Have you worked with kombucha before?
I've been a huge kombucha fan for years and was even a speaker at the first Kombucha Summit. The kombucha community is super curious and has remarkable cohesion. I sometimes miss that among water experts. For good kombucha, high-quality water is essential. You can taste the difference immediately. I work with several Berlin kombucha producers, and we install our Leogant water filters in their kombucha breweries. It's super exciting to accompany these manufacturers on their journey and influence their different kombucha flavors.

Why do you think filtered water is better for kombucha fermentation?
Differences between filtered and unfiltered tap water
In my opinion, there should be a clear distinction between water for machines and drinking water for humans. Water utilities do a great job, allowing us to access clear water at any time in our daily lives. Nevertheless, their filter system understandably cannot achieve spring water quality, as found in nature. If we consider water as a food, don't we all want to consume the highest possible quality?
- Here I have two options: Either I buy high-quality spring water in a glass bottle at an organic store, or I get a water filter and treat my tap water myself.
- The Result: Our bodies are vitalized and better supported in detoxification than usual, and of course, this also significantly affects kombucha fermentation.
Effects of vitalized water on kombucha
Experience shows that filtered and vitalized water significantly improves the fermentation process. Just as flowers and herbs last longer with vitalized water, the SCOBY thrives on premium water quality. The tea fungus grows faster, the alcohol content is different, and the SCOBY is less susceptible to mold – resulting in a higher quality, vitalized kombucha.
Filtered water gives kombucha a special taste
Depending on the type of filtration and the conditions of the region from which the water originates, water quality also influences the pH value and thus the taste of the kombucha. The water should not be too hard, but also not too soft. This is, of course, a matter of taste. The less minerals in the filtered water, the more acidic the water is. This affects the pH value during kombucha fermentation. For tea and coffee, slightly softer water is beneficial for the taste. The tea fungus prefers it a bit more acidic. Decalcifying water can therefore have enormous disadvantages, which then also affect the taste of the kombucha.

What initial tips can you give our readers at home to improve their water quality for fermentation?
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Always let the tap water run until it is noticeably colder. Most of the dirt is actually in the pipes and fixtures. This can take 30 seconds on the ground floor, but up to 3 minutes on the 8th floor.
- What also works for a start, if you don't have a filter, is to boil the water. Then let it cool down and run it through a coffee filter to remove suspended solids, limescale, and dirt. This naturally reduces the hardness.
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Semi-precious stones, such as rock crystal, amethyst, and rose quartz can vitalize the water. Simply place a few of them with your water in a water pitcher. It is best to always use tumbled semi-precious stones, as bacteria can settle in the crevices of untumbled ones and they are harder to clean.
- In general, it should be noted that bottled water is even less controlled than our tap water. Exceptions are some spring waters in glass bottles, which can usually be found in organic markets. Examples include Preußenquelle and St. Leonhard.
- Start with the AVAIO countertop filter or another LEOGANT system. With the voucher code KOMBUCHERYXXLEOGANT2021X you get 10% off your first purchase in the LEOGANT online shop.
A Strong Water Community as a Future Vision
What is your personal mission for the future?
In my post-Leogant vision, after 12 years in the "water business," I simply want to represent the entire fascinating topic of water on a meta-level. I want to build a strong water community, because, as we know, working together is always better than against each other. I also want to develop great concepts around water with competitors and raise awareness for the topic.















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