Does Cryo Maceration Make Wine Better?

Bending Branch Tannat

On a 96-degree day — in October — I was visiting Texas Hill Country care of Texas Fine Wine, sipping on a glass of tannat produced by the region’s Bending Branch Winery. Given that the extreme climate was on full display that day, I might have braced myself for a wine that was massive. Tannat is named, after all, for its tannic capabilities, and again, it was a blistering hot day in the autumn. I expected the wine to have a Texas-sized personality: huge, bold, gripping. And yet, even as Dr. Robert W. Young, winemaker of Bending Branch, was describing a winemaking process that sought to extract more tannin from the grapes, I found the wine to be full-bodied, but not outsized. Complex and subtle. Silky, even. Bending Branch had evidently earned its right to be called the Tannat House of Texas, since they had obviously cracked the code on the variety.

Dr. Robert W. Young, “Dr. Bob” of Bending Branch Winery

So, how does a tannin-forward grape in an unyielding climate produce wines with such finesse? The answer, according to Dr. Bob (as he is colloquially known in the region) is cryo maceration. “From day one when I started making wine I started doing side by side fermentations, one with cryo, and one with the more traditional method,” says Young. And as his cryo-macerated wines racked up both local and national accolades and awards right out of the gate, making Bending Branch one of the most awarded wineries in Texas, the proof of the efficacy of cryo (as it is colloquially known) is in the proverbial pudding. Cryo maceration also has more going for it than just an ability to turn tannins into silk, however. It also potentially has a role to play in the future of winemaking at large.

What is Cryo Maceration and How Does it Work?

Freezing grapes using cryo maceration

Cryo maceration is simply the process of freezing grapes to sub-zero temperatures for a period of time prior to fermentation, which breaks down cellular structures and allows for more compounds to be extracted from the grapes during fermentation, specifically compounds related to color, flavor, and tannin. “Ice crystals form in cell walls, and physically break open vacuoles in the cytoplasm,” Young explains, which allows access to molecules that were previously bound up and inaccessible, even with crushing.

Utilizing shipping containers that were already outfitted for frozen transport, “we freeze the grapes at about minus nine degrees centigrade, and keep them frozen for a minimum of two weeks,” says Young. While the process of freezing grapes is relatively simple in theory, understanding the science of what cryo maceration allows is decidedly more complex.

What Does Cryo Maceration Do to Wine?

Dr. Bob in the vineyard

Dr. Bob’s interest in cryo maceration began at the research level, as befits someone with a decades-long medical and public health career that was defined by innovation and creative problem-solving. After relocating to Texas for retirement to be closer to his daughter, and having met winemakers in the Fredericksburg area, winemaking presented an opportunity to put his professional impulses to work in a new field. While earning a Certificate in Winemaking from UC Davis, the problem he aimed to solve creatively was how to make red wine in Texas that effectively matched the boldness of the region.

“I had noticed in the early 2000s when I was drinking red wines in Texas, that they were not full-bodied,” says Dr. Bob. “They were too light. They didn’t have the substance, the color, and the complex flavor profiles,” he says, which is actually a factor of the extreme heat experienced in the region. “It accelerates sugar production, but it slows down the production of polyphenols,” he says. “It slows down color. It slows down tannins. It slows down flavor production. In scientific terms, it’s called the ‘uncoupling’ of sugar and phenolics.” Wines made in this heat had the sugar capacity to produce high-alcohol wines, but not those that were balanced with other crucial elements.

Young found studies on the effects of cryo maceration in France that showed how it could help extract more of these compounds, but that wasn’t being put to practical use. The particular study he cited showed that freezing batches of cabernet sauvignon, cabernet franc, and merlot resulted in close to 50% more extraction of both tannins and anthocyanins (color compounds) in the grapes during fermentation.

“That’s a pretty revolutionary finding,” says Young, “but I couldn’t find anybody in the world that was doing it. It was just a paper somebody published, and nothing ever happened. So I thought, well, I’m going to do it, because this may be a significant solution to the problem.” Young’s own experiments with cryo maceration yielded similar results, extracting significantly more tannin and color compounds from grapes such as tannat, cabernet sauvignon, and malbec.

What’s more, Young found research material by Roger Corder, a pharmacologist and author of “The Wine Diet” who sought to isolate compounds in wine that may have health-positive attributes. Corder’s research pointed to the presence of procyanidins, polymers that include color and tannin molecules in a particular ratio that may have a positive effect on blood vessel dilation. (Polymers are essentially chain links of different molecules.) “As a doctor, I was really intrigued with it,” he says. “This compound might be beneficial. Why not try to produce more of it in the wine we make?”

Procyanidins are also enabled by cryo maceration, insofar as the process helps to create the desirable ratio between color and tannin, which also improves the texture of the wine. “From a taster’s perspective, they’re smooth as silk,” says Young. “If you have all of your tannins in that form, you have no grippiness. You have no bitterness.”

Implications of Cryo Maceration to Offset Climate Change

Bending Branch Winery cryo bins

Texas wine may still be emerging, but in the face of a changing climate, the world can stand to learn from a region that routinely experiences the level of heat that Texas brings. “Texas is a five [on the Winkler index] but we’re really hotter than five,” says Young. “We’re a five plus.”

Among techniques that winemakers are using to offset the effects of climate change, Young believes cryo maceration is, so far, an underutilized one. “You can’t change the climate,” he says. “You can try to do some things in the vineyard, but they’re minimal. Everybody’s kind of focused on the vineyard, but I focused on the winemaking.”

Young has been invited to speak on the topic, primarily around Texas, but also in other hot winemaking places such as Spain. He hopes that cryo maceration has potential for other winemakers, while acknowledging that the logistics of freezing grapes can present challenges. (But also benefits — the freezing process delays fermentation for certain varieties during harvest when many winemakers are juggling numerous grapes at once.) “I think in the long run, this stuff is going to catch on,” says Young. “Extraction techniques are important,” he says, “otherwise you’re going to have to plant something different or plant something somewhere else.”