Rooibos Left the Cup and Went to Work in a Wine Tank

The cellar at Audacia in Stellenbosch, on an evening in 2010, held the ordinary problem of every cellar since wine was invented. Juice wants to turn. Air gets at it, enzymes get at it, and what was fruit becomes vinegar. For most of two centuries the answer has been sulphur dioxide, a cheap and efficient additive that mops up oxygen before oxygen can reach the wine. Trevor Strydom, who founded Audacia and makes its wine, had been at it a long time that day. His daughter brought him a cup of rooibos.

What happened next is the reason we are writing this at all. Strydom did not drink the tea and go home. He looked at the cup and thought about antioxidants, which is what rooibos and honeybush are quietly full of, and wondered whether the fynbos growing on the hills behind him might do the job the sulphur was doing. In 2011 he patented the process, and the South African Wine and Spirits Board approved it, a story a wine magazine later told in full¹. The company built around that patent was called Red Dawn.

What the red bush is actually doing in the barrel

The mechanism is less mystical than it sounds, which we consider a point in its favour.

Tannins are polyphenols, the same broad family of plant compounds that live in wood and leaves and, of course, in tea. Strydom's early method was direct to the point of bluntness: take the wood of the rooibos and honeybush, toast it, and steep the chips in the fermenting juice, so that the plant's own polyphenols leach into the wine. By the mid-2010s, Audacia's winemaker, Michael van Niekerk, was making red wine this way⁶, without added sulphites, and describing the result as rounder on the palate and fresher in its fruit, with a well-integrated tannin structure and a subtle tartness the wood itself lent it.

KWV, one of the country's large producers, took the technology up separately and made its own version, an Earth's Essence Pinotage launched in November 2014 and billed as the world's first natural Pinotage with no added sulphites⁴. Their method was homelier still. Branches of rooibos dried in the sun, ground to a powder, and put into what is functionally an enormous tea bag, submerged in the wine at a rate of about five grams to the litre². A pot of tea, in other words, brewed in a tank of Pinotage.

Marco Ventrella, KWV's chief viticulturist, described the thinking plainly⁵. "The initial concept was to introduce the actual wood from the Rooibos and Honeybush into the fermenting juice and with that extraction, it extracted the polyphenol that helped prevent the oxidation." They have since moved on to a purified tannin essence drawn from the wood, which he says works better than the wood itself.

The polyphenols do two useful things. They scavenge oxygen directly, and they inhibit the oxidase enzymes, laccase and polyphenol oxidase, that would otherwise get on with spoiling the wine. That is broadly the same work sulphur does. Strydom has argued there is a bonus in it: plant tannins, he says, "unmasked and unleashed the fresh fruit and delicate flavors often suppressed by sulfur." KWV's own tasting notes for the Pinotage describe it as upfront and sweet-fruited, cranberries and Turkish delight, dark chocolate on the nose, with nuts and rooibos and honeybush and sweet basil somewhere in the middle of it, and a grippy tannin structure that lingers.

By 2024, fourteen years after the cup of tea, the thing had grown into Rooibos Earth's Essence³: a retail range of wine, a 3.8% beer, and a 3.8% apple cider, all preserved with rooibos and honeybush extract rather than synthetic sulphur, sold exclusively through Checkers LiquorShop stores across the Western Cape, with support from the Shoprite Group's supplier mentorship programme. The wine comes off Strydom's own twenty-three hectares in Stellenbosch, about a hundred and thirty-five tons of grapes a year. The beer and the cider are brewed at Darling Brewery.

Now the part where we are honest with you

We would be poor custodians of the red bush if we told you only the pleasant half.

Gavin Lavi Sacks, a professor at Cornell, has looked at this premise and does not much like it¹. Tea tannins, he says, are "rather weak antioxidants in comparison to SO2," and would not stabilise a wine as effectively, because the two substances protect against oxidation by genuinely different mechanisms. This is not a small objection. It is the objection. Sulphur is very good at its job, which is precisely why it survived two hundred years of people looking for something better.

There is a bureaucratic wall as well, and we say this with the fellow-feeling of one ministry for another. American approval requires pharmaceutical-grade documentation before the Alcohol and Tobacco Tax and Trade Bureau will accept the process. That paperwork has not been done, so these bottles have not reached the United States.

And then the third thing, which is the one we find genuinely interesting.

The reason people want it is mostly not true

A great deal of the consumer enthusiasm for a no-sulphites-added wine rests on the belief that sulphites cause headaches. The evidence for that is thin. There is little solid work linking sulphites to the wine headache at all, and the likelier culprits are histamines, the tannins themselves, or the plain combination of alcohol and not enough water.

People who react to sulphites do exist, and their reactions are real. About 4 to 5 percent of people with asthma have some form of sulfite sensitivity⁷, and it is asthma, far more than a general allergy, that carries the risk. The listed reactions include wheezing, chest tightness, coughing, sneezing, and hives. A headache is not among them. And the doses involved are not as dramatic as the fear suggests. Dried apricots can carry up to around a thousand parts per million of sulphites. A typical dry wine, with sulphur added, runs nowhere near that⁸: the American label warning kicks in at ten parts per million, but that is a disclosure floor, not a description of what is in the bottle. Nobody has ever blamed the apricots.

There is one further wrinkle, and it is the sort of fact we enjoy. Sulphites occur naturally in fermented grape juice. Fermentation makes them, unbidden, as a byproduct of itself. So no wine has ever been sulphite-free, including these. "No sulphites added" is an accurate and meaningful statement about what the winemaker put in the tank. It says nothing about what is already in the glass, and the coverage of the KWV bottle was careful to footnote exactly that⁵, calling sulphite-phobia a modern wine myth.

So here is where the whole business settles. A working chemist patented a real technique, cleared it with a regulator, refined it for fourteen years, and put it on shelves. The technique does what he says it does, somewhat less well than the sulphur it replaces. And the appetite that helps sell it comes largely from a worry the science does not support, while the claim actually printed on the label happens to be true.

We note in passing that this is a different thing from rooibos gin, or a rooibos cocktail, of which there are now several and some of them are good. Those use the red bush as a flavour. Strydom is using it as a piece of machinery, standing in for a chemical rather than adding a taste.

Which is a strange fate for a plant that grows nowhere on earth but the Cederberg, in sandy acid soil under a hot dry sky, and whose entire career until the 2010s was to be poured into a cup and left alone for as long as you liked. It has been given a night shift in a wine tank, five grams to the litre, in a bag.