Every year, when the first elderflowers bloom and the days become longer, we return to the same question:
How do you capture a season in a bottle?
For thousands of years, humans have looked for ways to preserve abundance. Sometimes that meant drying, salting, smoking, or fermenting. But summer offers another possibility. With a little sugar, water, and patience, flowers, roots, and microbes can be transformed into sparkling drinks that tell the story of a place and a moment.
During our field workshops, we often explore three different approaches to spontaneous and guided fermentation. They each rely on different microbial communities, but all share the same principle: creating an environment where beneficial microorganisms can thrive and transform simple ingredients into something alive.
The ginger bug, the elderflower champagne, and kombucha each represent a different way of working with fermentation. Together they form an excellent introduction to the world of fermented beverages.
The Fermentation Triangle
At first glance, these three drinks look similar. They all contain water, sugar, and microorganisms. Yet the source of those microorganisms changes everything.
A ginger bug relies on the microbes naturally present on fresh ginger.
Elderflower champagne relies on the yeasts and bacteria living on the flowers themselves.
Kombucha relies on a mature microbial culture that has already been cultivated and passed from brewer to brewer.
One is wild, one is seasonal, and one is domesticated.
Learning all three teaches us that fermentation is not a recipe but a relationship with microbial ecosystems.
Ginger Bug
Growing Your Own Starter Culture
A ginger bug is one of the simplest fermentation starters you can make. Fresh ginger carries a rich community of wild yeasts and bacteria on its skin. When fed with sugar and water, these microorganisms begin multiplying and produce carbon dioxide, acidity, and aroma.
Over a few days, a bubbly starter develops that can be used to carbonate fruit sodas, herbal infusions, and seasonal drinks.
Base Recipe
Day 1:
- 25 g fresh ginger, grated with skin on
- 25 g sugar
- 50 g water
Mix everything in a clean jar and leave at room temperature.
Day 2 and Day 3:
- 25 g fresh ginger
- 25 g sugar
- 25 g water
Stir well after each feeding.
After three days, you should have approximately 100 ml of active ginger bug. At this point, the culture should smell fresh, spicy, fruity, and show visible signs of fermentation.
This starter can be added to approximately 1 litre of sweetened herbal tea, fruit juice, or seasonal infusions. Rhubarb, berries, apples, peaches, grapes, or even herb-based drinks work beautifully. The ginger bug acts as the microbial engine, transforming these ingredients into naturally sparkling beverages over the following days.
Unlike kombucha, a ginger bug remains highly adaptable. It quickly reflects the ingredients around it and is one of the easiest ways to explore wild fermentation at home.
Elderflower Champagne
Fermenting the Landscape
If kombucha teaches us to care for a culture and a ginger bug teaches us to cultivate one, elderflower champagne teaches us to trust the landscape itself.
Fresh elderflowers arrive already covered with wild yeasts. These invisible passengers have evolved alongside the plant and wait for an opportunity to feed on sugars. This is why elderflowers should never be washed before fermentation. Washing removes the very microorganisms responsible for the transformation.
For centuries, people across Europe have fermented elderflowers into lightly sparkling drinks. Every region has its own variation, but the principle remains the same: flowers, sugar, water, and time.
Building the Starter
- 5 g fresh elderflowers
- 20 g sugar
- 100 g water
Mix everything in a clean bowl or pot and cover with a cloth. The cloth protects the mixture while still allowing oxygen exchange, encouraging the yeasts naturally present on the flowers to multiply.
Adding a slice of lemon or a little lemon juice helps acidify the environment and encourages a healthy fermentation. It also discourages less desirable microorganisms during the first stages of growth.
After one to two days, the mixture should become fragrant, slightly fruity, and show the first signs of activity. At this point, the cultivated yeasts can be used to inoculate a larger batch of water with elderflower sirop, sometimes known in Belgium and Northern France as Champagne des Fées, Fairy Champagne.
Or if just added with 90% water, a nice fizzy drink. The resulting drink captures more than the flavor of elderflower. It captures the microbial fingerprint of a particular field, hedge, or garden at a specific moment in the year.
Kombucha
A Culture Passed Between Brewers
Kombucha takes a different approach.
Instead of relying entirely on wild microbes, kombucha begins with an established ecosystem of bacteria and yeast that has been maintained and shared by brewers over generations.
Base Recipe
- 1 litre water
- 60 g sugar
- 5 g tea (black, green, or a blend)
- 150 ml mature kombucha (backslop)
- 1 SCOBY (optional)
Brew the tea, dissolve the sugar, and allow the mixture to cool completely before adding the mature kombucha.
The SCOBY itself is optional. Most of the microbial activity lives in the liquid rather than the cellulose mat. The important element is the backslop, which immediately lowers the pH and creates a safe environment for fermentation.
Cover the vessel with a cloth or breathable lid and protect it carefully from fruit flies. These tiny insects are attracted to fermentation and can quickly contaminate a batch.
Over the following 7 to 14 days, yeasts convert sugars into alcohol and carbon dioxide while bacteria transform that alcohol into organic acids. The result is a balanced fermentation that can be propagated indefinitely and adapted to seasonal ingredients.
Three Paths, One Summer
These three drinks may seem different, but they all begin with the same gesture: creating a space where microorganisms can thrive.
The ginger bug starts with a root pulled from the soil. The elderflower starter begins on a flowering hedge alive with wild yeasts. Kombucha relies on a culture that has travelled from brewer to brewer, sometimes for decades. Each approach reveals a different relationship between humans and microbes.
Together, they show that fermentation is not simply a preservation technique. It is a way of paying attention to seasons, landscapes, and living ecosystems. A field of elderflowers becomes a sparkling drink. A forgotten piece of ginger becomes a starter culture. A jar of tea becomes a community of organisms capable of sustaining itself for years.
The Summer School field workshops are built around this idea. By learning a few simple techniques, you begin to see ingredients differently. Not as finished products, but as starting points for transformation. Every harvest becomes an opportunity, every season brings new flavors, and every fermentation tells the story of the place where it began.