As a re-occurring segment in this blog, I would like to discuss the health benefits of kombucha or ingredients commonly found in kombucha that have been substantiated with scientific evidence. It’s almost comical the gamut of health claims pertaining to kombucha. They range from curing AIDS to causing death. Kombucha apparently detoxifies the liver while at the same time acidifying it. The sheer volume of claims and the certainty with which they are made can be overwhelming. Even when studies are cited, it is difficult to discern the truth because some scientific writings almost seem to be written in a different language. Due to my background and work experience, I have spent a fair bit of time dissecting scientific documents and I will use these posts to clarify the findings to the best of my ability. A minor disclaimer, I am not a doctor, I am not recommending kombucha as a replacement for any medical treatment prescribed by a doctor, and lastly, the health claims discussed here were not discovered by me and do not necessarily represent my opinion.
The most cited instance of negative consequence pertaining to drinking kombucha was an unexplained death that occurred in Iowa. An otherwise healthy woman died of an unknown cause and her only symptom was blood acidosis. Another woman of the same town was also administered to the hospital because of shortness of breath. The only common link they found was that both women drank kombucha and the assumption was made that because kombucha is acidic, it may have contributed to her condition. However, after studying 24 kombucha drinkers from the same town, they were unable to link the kombucha as a cause of the illness. Even though the link between blood acidosis and kombucha was determined to be unsubstantiated by the FDA (not enough evidence to establish any type of certainty), because they never determined the cause of death, kombucha can sometimes be branded as potentially harmful. This is an unfortunate misrepresentation.
NERD ALERT (Science to follow): pH is a measurement hydrogen ions. Foods are basic and taste bitter when they have very few hydrogen ions (pH 7-14) and are acidic and sour when they have a ton of hydrogen ions to give away (pH 1-7). Bleach would be an example of an extremely basic compound (pH 12) while eggs would be mildly basic (pH 8). On the other side of the spectrum, milk would be a very mildly acidic product (pH 6.7) with common table vinegar being more aggressively acidic (pH 2.4).
Food for Thought: Most sodas (i.e. Coke and Pepsi) have a pH of around 2.5 and kombucha is well above that. If we compare a soda of ph 2.5 to a kombucha of pH 3.5, the difference in 1 pH means the soda is ten times as acidic as the kombucha. If consuming acidic beverages leads to blood acidosis, our country's larger demographic of soda drinkers (based on yearly sales (1,2)) would be among the first to develop symptoms.
Kombucha relies on a balance between yeast and bacteria to provide a variety of organic acids and unique flavors. These organisms may have a symbiotic relationship, but make no mistake, they are not friends. It is thought that one of the reasons yeast produces alcohol to slow down and even kill its competition. With that being said, if yeast is not properly managed, or if there is an over-abundance of yeast in the starter culture, a large quantity of alcohol could be produced. Additionally, yeast is very acid-resistant, so later in the fermentation, there is a chance that yeast is still active long after the bacteria has given up, leading to elevated levels of alcohol. This is compounded when secondary fermentation occurs in a closed vessel. Secondary fermentation is when an additional sugar source is added to the already fermenting kombucha and the kombucha is transferred to a closed vessel. Most bacteria is either aerobic (in the presence of oxygen) or anaerobic (without oxygen) where yeast is capable of both. When yeast is around oxygen it typically produces more yeast and very little alcohol, however, when that oxygen is removed, yeast ferments and produces alcohol and CO2 (3,4). Using Secondary fermentation is a great way to produce a carbonated product, however, alcohol is typically also produced. At Better Booch, we use several safety measures to control and monitor our yeast populations, such as cold crashing and keeping our product aerated, but I will get into that in another post.
For the home-brewers reading this article, I will discuss in-detail how to effectively avoid production of alcohol and keeping cultures healthy in future posts.
A silver lining regarding both blood acidosis and alcoholic content is that as the kombucha industry is growing, the FDA is beginning to pay more attention to kombucha companies, which is a good thing. Alcohol production is usually caused by lack of control or lack of understanding of fermentation. A class action lawsuit resulted from a few companies that have been operating above the 0.5% alcohol limit. New regulations will enforce a safer, more well-understood product for consumers.
Lastly, I wanted to talk about the least discussed and arguably the most important health benefit: Kombucha is a delicious, low calorie beverage. Kombucha begins it’s life as a sweet tea, but the probiotics soon convert the organic sugars into great tasting esters, organic acids, and alcohols. The beauty of these fermentation by-products is that most add unique flavor and crisp acidity without adding any calories. What little sugar is left coordinates with the acid to produce a sweet and sour canvas that accents the tea, fruit, and spice character. While some kombuchas, home-brewed or otherwise, may be touted as medicine because it would be hard to imagine drinking them for fun, the landscape of kombucha is shifting towards an artisanal product, customized to the tastes of those who want something complex and refreshing. While it is difficult to properly quantify the health benefits of doing something we enjoy, I think the benefit of drinking something that tastes good without bringing about the guilt of splurging on extra calories is intangible, but important.
That concludes the first section discussing health benefits. In future sections I will go over the nutrients found in kombucha, probiotics, cancer studies, and a variety of other topics. If you would like to suggest a specific topic for this section, have a general fermentation question, or would like me to go over something in particular for future posts, please leave a comment below!
3) Tonsmeire, Michael. (2014) American Sour Beer: Innovative Techniques for Mixed Fermentations. Brewers Publications.
4) Katz, Sandor Ellix. (2012) The Art of Fermentation. Chelsea Green Publishing.