Kombucha is often marketed as a wonder drink. Google its health benefits and you'll find articles about curing cancer and reversing degenerative diseases.

In reality, no such claims have ever been verified. The closest the U.S. Food and Drug Administration has come to testing kombucha is a study into claims about green tea—which is often a base for kombucha—and cancer reduction. However, the FDA found there wasn't enough evidence to prove green tea could reduce consumers' risk of cancer, and the agency prohibits retailers from listing such claims on products.

So what is the kombucha craze all about, and why do people swear by it as a health tonic? To find out, we chatted with four local 'booch experts: Iris Briand, a registered dietitian nutritionist and founder of Portland's Sol Food Nutrition; Liz Winters, a nutritional therapy practitioner who hosts kombucha-making classes at Sprout Wellness; Mike Adams, a food scientist at Oregon State University's Food Innovation Center in Northwest Portland; and Wendy Jensen, co-founder of Oregon City's NW Ferments, which sells starter cultures and fermentation supplies.

They told us about the science behind kombucha and what it actually does for your health. Spoiler alert: It's not as miraculous as you may have believed.

WW: What is kombucha exactly, and how is it made?

Wendy Jensen: It's a probiotic drink that's made using a starter culture that grows in tea and sugar—fermented, it turns into kombucha, which contains a lot of live, active bacteria.

Mike Adams: In the starter culture, there is a mixture of organisms that take the sugar and ferment it to ethanol. In the second stage of fermentation, bacteria take the ethanol and metabolize it into acetic acid. That's why you get the vinegar smell.

How long has it been around?

Liz Winters: From what I understand, it's been around thousands and thousands of years and it started in Asia.

Iris Briand: I don't really know. I just know that in the '60s it kind of had a little bit of a hit. My mom says in the '60s and '70s, everyone was brewing kombucha, but there weren't really commercial varieties. Around the 2000s is when more commercial varieties started coming out. My mom and all of her friends were just totally flabbergasted that something as odd as kombucha would be trendy.

Is it possible for gross stuff like mold to grow while it's fermenting?

Adams: That is always a concern. Oftentimes, it's brewed at a high enough temperature and then cooled quickly enough to discourage pathogens from growing. Once ethanol production starts, it does a pretty good job of prohibiting pathogens. That being said, anything can happen if any of those steps are handled poorly. I always warn people who make kombucha at home to use really good food-safety practices.

Jensen: It can start to mold, and it's really obvious when that happens, because it turns blue-green or black and looks furry. If that happens, toss the scoby [starter culture] and try again.

Why is it purportedly so good for you?

Briand: Well, not all kombucha is created equal. Certain companies have a ton of probiotics per bottle. Others are more a great alternative to soda because you're getting a quarter or fifth the amount of sugar you'd be getting from another drink but there's not a whole lot of probiotics in them. It's really important to have probiotic-rich food sources to make sure we boost our immune system and digestive health.

Winters: It has a lot of beneficial probiotics that are good for our gut microbiome. Improving digestion is really helpful for mood boosting. It's a happy, feel-good drink.

Why do kombucha bottles explode when they get old?

Jensen: Because it's live in there. It never stops fermenting. When you refrigerate it, it just slows the fermentation process down.

Briand: While kombucha is fermenting it creates CO2, which is quite explosive. When you bottle kombucha, CO2 under pressure wants to get out.

Is it possible to drink too much of it? If yes, what happens to you?

Briand: You cannot hardly get too many probiotics, but you could definitely overdo the sugar.

Winters: If you're not used to eating fermented foods, it can have a laxative effect. It's important to build up to drinking it. I tell people not to drink more than 16 to 20 ounces a day, so it's not taking the place of other important things like water.

Adams: I would imagine but I don't know what the dose would be. At the base level, you can consume too much water.

Could you ever drink enough kombucha to catch a buzz?

Jensen: No. Somewhere someone did a study to try to get drunk drinking kombucha, but they just ended up getting sick because they drank so much. It does make a good mixer if you put alcohol in it, though.

Briand: It would be so unlikely. Every bottle has like 0.05 percent alcohol. You'd have to drink four bottles to even get to 2 percent.

Winters: By the time you drink that much, your body would have metabolized the small amount of alcohol.

In 2010, some state chapters of Alcoholics Anonymous complained to Whole Foods about varying levels of alcohol content in kombucha. Should people who struggle with alcohol addiction avoid it?

Winters: That is up to them and depends on the situation. When people are trying to switch up their evening glass of wine, it can be a really helpful replacement. A lot of what people find they are connected to is ritual. Pouring kombucha in your wine glass can be a really nice replacement.

Briand: It is quite unlikely there's enough alcohol in most kombuchas on the market to be a problem for recovering alcoholics. However, if a person recovering from alcoholism wanted to be extra cautious, they could choose the clear bottles of GT's Synergy Kombucha, for instance, instead of the dark bottles of that brand, which are fermented longer, creating a bit more trace alcohol. The optimal recommendation is to consume a third to half of any bottle and keep the rest in the fridge. That's the serving I recommend anyway for all my clients.

Some people claim drinking kombucha can help fight cancer, arthritis, and other degenerative diseases. Is there any truth to any of these health claims?

Winters: I'm wary of anything that calls itself a cure-all. Ferments have a really good place in our diet, but kombucha is not a wonder drink.

Briand: Replacing other crap with kombucha can certainly be beneficial. But it's not the only thing. In America, we want one pill that's going to do everything, and that doesn't exist. Everything is part of a holistic program.

Adams: The best thing for you in kombucha is the water. Whatever keeps you hydrated is good for you. That's easy to prove.