Half science. Half delicious drink. Read my guide..

Nathan Hague

Introduction:

For thousands of years, kombucha has been made the same way: Fermenting tea with sugar, and a symbiotic culture of bacteria and yeast. Riding on the back of the drink’s popularity, there has been debate in the scientific community about the presence of alcohol (ethanol) in kombucha. In this article, we will examine the fermentation processes that occur during the fermentation of kombucha and how they contribute to the formation of alcohol in the final product. Finally, we will answer the question of whether alcohol in Thailand kombucha could affect your choice in drinking it, with the facts gained from this article.

Kombucha Fermentation Process Basics

Kombucha fermentation is a complex process involving the symbiotic action of yeast and bacteria. The yeast ferments the sugar in the sweet tea mix into alcohol, while the bacteria ferment the alcohol into acetic acid, producing a sour and tangy flavor profile.

For the more scientific readers, the initial fermentation process can be represented by the following equation:

C6H12O6 (sugar) -> 2 C2H5OH (alcohol) + 2 CO2 (carbon dioxide)

During the fermentation, yeast and bacteria compete for resources and the pH of the sweet tea mix changes. The yeast produces ethanol, and will continue to do so until the ethanol concentration reaches a level that is toxic to yeast cells, at which point the bacteria take over and produce acetic acid in its fermentation process.

Types of Yeast and Bacteria:

There are several types of yeast that can be found in kombucha, including Saccharomyces cerevisiae, Zygosaccharomyces kombuchaensis, and Candida stellata. The specific types of yeast and bacteria present in kombucha will depend on the recipe and the environment in which it is fermented. Wild yeasts can be unpredictable in commercial kombucha production, so some producers choose to keep a proprietary yeast strain mix and ferment in a closed environment to keep fermentation results more predictable and stable.

The bacteria in kombucha include Acetobacter xylinum and Gluconacetobacter kombuchaensis. These bacteria produce acetic acid, which helps lower the pH of the liquid and make it more acidic. Acetic acid is the main reason vinegar tastes the way it does, which is why some sour kombucha connoisseurs might also drink apple cider vinegar. This acidic environment makes it difficult for yeast to grow, which helps prevent the production of excess alcohol.

This delicate interplay between yeast and bacteria in kombucha results in a symbiotic relationship that allows the two microorganisms to work together to produce the carbon dioxide, ethanol, and organic acids that give kombucha its characteristic flavour and fizziness.

Kombucha Fermentation Process Deeper Dive

Now that we have covered a high-level view of the kombucha fermentation process and why there is alcohol in Thailand kombucha, it’s time to dive deeper into the scientific facts.

Temperature and Environmental Factors:

Temperature is crucial in the fermentation process of kombucha. The optimal temperature range for yeast and bacteria growth varies, so it is important to maintain a consistent temperature during fermentation. For instance, yeast species S. cerevisiae grows best at temperatures between 20°C and 22°C (68°F and 72°F), while bacteria species A. xylinum prefers temperatures between 24°C and 26°C (75°F and 80°F).

Despite the variations in yeast and bacteria composition, temperature continues to be one of the main variables in ensuring a successful kombucha fermented batch. Kombucha is a mesophilic fermentation process, meaning it is most successful at moderate temperatures ranging from 68-85°F (20-29°C)

At temperatures higher than 85°F (29°C), the environment becomes increasingly favourable for the growth of unwanted bacteria, such as Klebsiella, Enterobacter, and Escherichia coli. These bacteria are known to produce a range of harmful toxins and are associated with a variety of foodborne illnesses, such as food poisoning and gastroenteritis (Boyle & Robbins, 2013).

Additionally, elevated temperatures can also increase the risk of spoilage and reduce the shelf life of the kombucha. This is due to the fact that high temperatures can create an environment that is conducive to the growth of yeast strains, such as Candida and Saccharomyces, which can produce off-flavours and undesirable aromas in the final product (all commercial Thailand kombucha producers will have a failed batch once in a while – and it’s usually down to temperature controls failing and yeast growth adversely affecting the batch!)

So, you now know why it’s essential to maintain consistent temperatures during the kombucha fermentation process to ensure that the yeast and bacteria are able to ferment the tea effectively while also preventing the growth of harmful pathogens and other unwanted microorganisms.

pH And Acidity Considerations

In addition to temperature, the pH of the kombucha also plays a critical role in the fermentation process. The optimal pH range for kombucha is 3.0-4.5, as this range allows the yeast and bacteria to effectively ferment the sweet tea mix while also preventing the growth of unwanted microorganisms. The pH of the kombucha can be monitored using pH strips or a pH meter, and adjusted if necessary using food-grade acids such as lemon juice or vinegar (or professional lab testing like we use here at KombuchaWOW!)

Sugar Source

Another important factor that affects kombucha fermentation is the sugar source. The yeast and bacteria in kombucha feed on the sugar in the tea to produce the carbon dioxide and ethanol that are the byproducts of the fermentation process. Different types of sugar, such as white sugar, brown sugar, and honey, can produce different flavours and alcohol levels in kombucha, so it is important to experiment with different sugar sources to find the optimal one for your kombucha recipe. Just to reiterate though for the health conscious reading this: By the time the fermentation process has concluded, most of the sugar source has been exhausted by the fermentation process which is why unflavoured raw kombucha is considered such a healthy drink.

Hard Kombucha in Thailand

In recent years, there has been a growing trend of hard kombucha in Thailand. Hard kombucha is a type of kombucha that has a purposely-higher alcohol content, typically around 5% to 8% by volume. This trend has been fuelled by the growing popularity of craft beers and the desire for new and unique flavours.

Hard kombucha is typically produced by allowing the kombucha to ferment for a longer period of time or by adding additional sugar to the liquid. This increases the alcohol content, but also increases the acetic acid content, which can give the drink a sour taste.

I haven’t focused at all on the alcoholic kombucha category in this article, as I suspect most readers want to know whether there is alcohol in Thailand kombucha they are buying off the shelf at a Thai grocery store, right?

In conclusion

The alcohol content of kombucha can range from 0.5% to 2% ABV for home-made kombucha, but alcohol in Thailand kombucha purchased from commercial Thailand kombucha breweries will always be less than 0.5% ABV as stipulated by Thailand brewing and Consumer Laws as of March 2023.

The production of alcohol in standard non-hard kombucha is a natural result of the yeast and bacteria working together to ferment the sugar in the tea. The amount of alcohol produced in Thailand kombucha is influenced by many factors, including the yeast and bacteria composition, temperature, pH, and sugar source. By carefully monitoring these factors and adjusting them as needed, Thailand kombucha brewers like us here at KombuchaWOW! can produce kombucha with the desired alcohol levels of < 0.5% ABV, flavour profiles, and acidity levels.

While this range is considered low and the beverage is not considered to be alcoholic in most countries – it is important know that Muslims must consider all home-made kombucha to be haram, as alcohol levels cannot be guaranteed to be under 0.5%.

Given the fact that the alcohol content of kombucha can be affected by several factors, including the recipe, the yeast and bacteria used, and the environmental conditions – we advise Muslim Consumers stick to store brought brands from brands like ourselves at KombuchaWOW! as we have our Thailand craft kombucha batches checked by independent food testing laboratories.