Is Kombucha Safe?

Recently I met a woman who brews kombucha, and I couldn’t help but ask if she had an extra scoby (symbiotic culture of bacteria and yeast) so I could try my hand at fermenting it myself.


A kombucha scoby is a flat, rubbery disc that floats in a sweetened tea medium. There are a number of organisms in the mix, but for simplicity’s sake, we’ll say that there are two classes of critter involved, various yeast species, which ferment the sugars into alcohol, and various vinegar-forming bacteria, which ferment the alcohol into several organic acids, giving the finished drink an apple cider vinegar pucker and a bunch of interesting components that the average American diet likely doesn’t provide.

Some people praise kombucha as a miracle elixir that cures everything from baldness to arthritis to cancer; others insist it is untested and dangerous.

Look, kombucha had me at “fermented by a scoby.” I just can’t pass up what I’m calling a Microbial Village. That said, I want to understand what risks there are so I can minimize them procedurally, or make an informed decision about whether kombucha is safe to drink.

As far as I can tell, the CDC has documented a total of three (3) hospitalizations linked to kombucha – two in Iowa in 1995, where one woman died, and one in 2009. All three were suffering acidosis, in which the body can no longer regulate its pH and the blood becomes acidic.

Those are real data points, and certainly many more people may have had less serious negative reactions that didn’t require medical attention.

That sounds like a pretty tough indictment of kombucha right there, until you consider that caffeine sends thousands of people to the hospital every year, and has been linked in a handful of deaths, especially from products where caffeine is mixed with other stimulants and can create synergistic effects in the body. Admittedly, caffeine is used daily by the vast majority of the population of the US, but still. You’d think that if kombucha were some sort of silent killer, there would be more than three documented cases of serious injury in 18 years.

And then there’s alcohol, which is really the point of this whole blog. It’s a lot of things, but I can say with clear conviction that I don’t drink for my health. How many hospitalizations result from alcohol on an average Saturday night?

So is kombucha safe? Store bought, I’m going to say yes, in that the product will almost certainly be free of contamination. Will your body love a sudden infusion of live culture enzymes and organic acids? That I can’t tell you. Will it impact how your body uses prescription drugs you may take? I can’t tell you that either. I have a friend who hasn’t eaten grapefruit in years because it was preventing proper absorption of certain of his prescription drugs.

What about home brewed kombucha? Is that safe? That’s a more qualified yes – kombucha can’t be airlocked as it ferments because it needs to breathe, and the home brewer is pouring in cooled, heavily sweetened tea that needs some time to develop a pH adequate to ward off pathogens.

So there’s a risk of contamination, and it’s higher than in most contemporary home brewing scenarios. Interestingly, the scoby usually floats at the surface and will grow to the width of its container, so a mature colony acts a little bit like an oxygen barrier, keeping the fermentable liquid submerged (though this is hardly a perfect seal).

And come on, in nature, a sugary solution will usually become alcohol, and an alcohol solution will usually become vinegar. These are not unique processes. These are the normal pathways of sugar decomposition, seen everywhere that fruits ripen or honeycomb becomes damp.

So, I’m having a good time playing with my new kitchen pet and enjoying the tasty drink it produces. I thoroughly wash my hands before interacting with it, and I monitor it carefully for off odors or signs of surface mold. I’m starting additional scobys as a fallback in case mold or other problems develop, and I was inspired to pour some very old live vinegar dregs into a jar with some bad wine to see if I can’t make a vinegar mother, a very similar complex, producing a similar product.

My kitchen may never be the same!

For another take, here’s a good piece from other experienced fermenters who’ve decided to steer clear of kombucha.

Founder’s Centennial IPA


Just a lovely beer, with plenty of citrusy, floral hops on a well-built malt backbone. 7.5% ended my weeknight beer sampling, but I’ll have this one again. Preferably beside a Bell’s Two Hearted (hey shorty) to compare flavors.

Pear Beer: Minty Fresh?

This is my “pear beer,” which has been conditioning in the bottle for two or three weeks. If memory serves, this was 55# of juiced pears (see – I’m a juiced fruit pro), 4# white sugar, boiled for an hour with 1 oz of Centennial hops. Nottingham yeasts.


What a strange flavor. There’s something almost “wintermint” (fake mint flavor) to it. I don’t know if I’d peg this as a pear-based drink if I didn’t know. It’s not bad, and certainly in same flavor profile range as a number of gluten free beers I’ve had (including some I’ve brewed) – and haven’t really cared for. This works for me more because it isn’t a beer, just hopped pear juice. But the aftertaste that lingers is fruity. It pours with a nice little foamy head, which is gone in a flash, and it’s got a nice hazy character like a wit. When someone brings me a crystal clear yellow beer, I ask for lime and clamato. It’s only right. I think this is going to be just fine – a couple more weeks in the bottle should give the carbonation a little more staying power, but I think this wintermint taste is here to stay. Holla for homebrewing experiments!

Stone 16th Anniversary Ale


Wow, this one continues to knock my socks off. So much going on with this beer. The hops package is Amarillo and Calypso… more on that in a bit. The grain bill includes a healthy dose of rye but not enough to classify this double IPA as a Rye Ale. The adjuncts include lemon verbena and lemon oil. This is a fragrant, smooth citrus explosion with a sweet body and a 10% ABV burn. Calypso is undeniably my favorite hops. With a fruity pear and apple bouquet, it brings the unique fragrance to this beer and a smooth fruity first taste. The Amarillo seems to pair well with the slight rye bitterness and brings a bit of a grapefruit zing to balance the Calypso fruit. The finish is appropriately bitter, clearing the palate for your next sip. Served with a medium rare ribeye and grilled squash, the beer held up well but did not overpower the savory beef flavor.

Bell’s Oarsman Ale

Saturday night’s alright for… well, working, in my case. But at 9 I closed out of my worky work and I’m going to do some housey things while Matt Smith puts a bowtie on the Doctor.


Hello! I saw this in the Sour section at Ale Yeah! yesterday and had to pick it up. I’ve really taken a notice of Bell’s beers lately, and I’ve also wanted to expand my understanding of sours.

You see, last weekend I shared a meal and a few (too many) drinks with Spyke and her wife over at the Brick Store Pub, and experienced some Jolly Pumpkin brett beer. Brettanomyces is one of those sideways yeasts that brewers tend to use sparingly, but I’ve always appreciated a little “brett funk.”

I haven’t had a lot of Jolly Pumpkin and haven’t loved what I’ve had, but whatever this beer was, it was like a liquid hatef—. It tasted like they’d crammed an orange into a gym sock after it had been through a marathon or three, then dipped the swollen citrus rotsweat of it all into a cup of coffee.

I couldn’t stop drinking it. Seriously. So I’ve had funktastic beers on my mind.

That’s a lot of throat clearing to get to the Oarsman.

Ignore everything above. This is nothing like it – not even a brett beer. Just a very sessionable (4%), light bodied, brightly colored sipper with lots of grape and lemon. Every third sip or so I get a nice bready aftertaste. The whole thing is quite pleasant. It’s definitely carbonated – it’s unpasteurized and bottle conditioned with a noticeable sediment at the bottom – but the foam lasted about five seconds and there wasn’t much to start with.

I’ve had some sours that have been surprisingly sweet, almost approaching Kool-Aid levels of grossness (sorry if that’s your thing). This isn’t. It’s tart and zesty, but the components come together to imply sweetness in the middle. It’s a good, grown up beer, a really smart approach to the style.

And that’s a relief, because I’m not really sure what I would do if I’d found that Jolly Pumpkin brett thing. Stare at it with a hateful lust? Pour it into a glass while I criticize the bottle for the shortcomings I find? Marry it just so I can divorce it bitterly later?

But the Bell’s Oarsman – now that’s a beer I can enjoy liking.

Green Flash West Coast IPA


A pretty solid yet typical IPA that carries a strong grapefruit bitterness in the finish. This beer is using Simcoe, Cascade, Centennial and Columbus hops. I suspect the bitter finish is from the Simcoe and maybe the Centennial while the nose lends itself more to the Cascade. This coppery dark amber beer is only slightly sweet, about 7% ABV and has a lot going on in the hops department. A good drinker on a hot summer’s day, but expect it to wreck your palate. You will want to pair your food accordingly. Served with Gran Marnier Pâté and a jalapeño cheese, I found it to overwhelm the subtle citrus notes of the pâté but accent the spicy cheese nicely.