Charles Bone wears a striped shirt and red cap while holding an example of a SCOBY during the kombucha-making class.

Something’s Brewing in the Arboretum

Kombucha 101, hosted by Charles Bone, teaches the College community to create their own versions of the popular, gut-healthy beverage.

As the sun set over Haverford Arboretum in early March, students and members of the local community gathered in the Facilities Management building to attend Kombucha 101, an introductory class for fans of the popular health drink interested in the homebrewing process. The class was hosted by Charles Bone, a horticulturist at Haverford for more than 10 years and, currently, a third-year student in the Barnes Foundation’s arboretum horticulture certificate program. 

“I normally just do Arboretum tours, so this is my first time hosting any kind of class,” Bone explained as guests rummaged for their pens and note-taking paper. 

Having bottled over 50 batches in the past year, Bone is a seasoned kombucha brewer who has accumulated a trove of knowledge about concocting this gut-healthy beverage. Here are a few tips and tricks from the class that amateur brewers can keep in mind as they prepare to start their first batch.

Swing-top bottles are the perfect vessels for bottling your homebrewed kombucha. Photos by Roger Lin ’25.

Kombucha’s ingredients are quite simple: only water, sugar, tea leaves, and a starting culture are required. However, Bone says quality is key.

“What goes into the vessel determines what comes out,” Bone explains. “How your kombucha tastes completely depends on the ingredients you use and your brewing process.” 

When it comes to making kombucha, a SCOBY is the star of the show, but what on Earth is it? An acronym for “symbiotic culture of bacteria and yeast,” the SCOBY is a mat of cellulose strands that floats on top of the brew and houses the microorganisms needed to ferment the beverage. Akin to sourdough starters, a SCOBY is very durable and can be used to produce dozens of batches, but it requires consistent care. 

“If you’re going out of town for a while, I recommend you toss it and start a fresh one when you get back,” Bone advises. 

But how does one acquire their own SCOBY? If you choose to find one online or at a store, be weary of expiration dates since they have a shelf life! If opting for a cost-effective method, using store-bought, bottled kombucha as your starter brew and letting it sit for two to three days will produce a new SCOBY. Once it is ¼ to ½ an inch thick, the SCOBY is ready to start brewing. 

Despite its integral role in the fermentation process, the SCOBY’s fleshy, yellowish appearance may be a bit startling at first glance.

“It doesn’t look like something you’d want to consume, but some people actually fry them like pancakes or blend them into smoothies,” Bone says. “I haven’t tried it personally, but it’s supposed to be pretty nutritious.”

Once you acquire your culture and are ready to brew, there’s no need to buy fancy, store-bought water to get started. Bone encourages brewers to use water straight from their kitchen taps but also recommends that they research their water profile beforehand. Things get tricky when chlorine is present, as it inhibits the kombucha culture from “doing its thing” and will cause the brew to go flat. If you find that chemical inhibitors are present in your water, they can be removed by boiling it for 10 to 15 minutes or resting it in a container overnight. Bone filters his tap water in a Brita and lets it sit out for a little while, which minimizes his issues with chlorine.

A successfully fermented brew requires the use of black or green tea to feed the kombucha’s bacterial culture due to the abundance of nitrogen and important minerals their leaves contain. Although traditionally made with black tea, Bone finds that a blend of black and green tea leaves tends to produce the healthiest culture, and using more green tea will make the kombucha smoother and dull its characteristic vinegary bite. Adding herbal blends to your tea base will give your kombucha different flavor profiles. However, Bone cautions brewers against issuing chai and other oily tea varieties, as these oils will cause the culture to degrade slowly. 

Because the kombucha culture uses sucrose during the fermentation process, real sugar is a must, and artificial or zero-calorie sweeteners just won’t work. Additionally, Bone cautions amateur brewers against using honey as they’re getting started.

“It can be a little dangerous since raw honey can introduce harmful bacteria into your brew,” he says. 

For the classic kombucha flavor, Bone recommends cane sugar and palm sugar for those looking for an unrefined sweetener alternative. Brown sugar and maple syrup are also fair game but tend to produce a more bitter flavor due to their high mineral content. 

After combining your ingredients in a large bottle or jar, seal the vessel lid tightly using a cloth and a rubber band. This is very important to prevent foreign contaminants from getting into your brew. Additionally, the brewing environment must be kept around 80 degrees to sustain fermentation, which can be accomplished using a store-bought heating wrap. Brewing time plays a big role in how your kombucha tastes: the longer you let it ferment, the more sugar the culture will consume and the bitterer your brew will be. 

Once finished, you can flavor your kombucha before bottling. Juices and fruit concentrates are popular choices, and Bone says he also likes to use frozen fruit that has been thawed and blended into a pulp. After your kombucha is prepared to your liking, it’s ready to be bottled and enjoyed.

If you missed out on Kombucha 101, there’s no need to fear! Bone says that the Arboretum is working to expand its programming, and fans of all things earthy should look out for more staff-hosted demonstrations and classes in the future.