Credit: Gerald Hoberman, Getty

Last December, I took a trip to Napa and visited a ton of wineries throughout the Valley. Though not the purpose of the trip, it became a study in tannins. The experience reminded me just how impactful vineyard and winemaking decisions can be on a wine’s profile. The largest differences in the wines came in the size, shape and structure of tannin, and I realized I should know more about why those differences exist because I clearly had preferences about them.

To learn more, I reached out to three winemakers whose wines I love in large part because of their tannins: Richie Allen of Rombauer in Napa, Shane Moore of Zena Crown and Gran Moraine in the Willamette Valley, and David Larson of Soos Creek in Washington State. Richie’s Napa cabernets are highly structured wines, but were also among the very small minority that do not overload the tannins. I found this remarkable because most of the Napa cabs I had, including many from esteemed wineries that receive (incorrectly, I believe) higher scores from the big reviewers than do Richie’s, hit you upside the head with dense, chewy and often times coarse tannins that prematurely dry the mouth and kill the flavor.

Shane’s pinots (and chardonnays) from Oregon are complex and rewarding at every price point they hit, and though one doesn’t talk about tannin in the same way with pinot as is done with other red varietals, I’ve found his pinots to achieve captivating textures.

For more information on Richie, Shane and their wines, you can read about my visit to Rombauer here, a profile of Richie here, and a profile of Shane here.

David’s Bordeaux-varietal wines from Washington, a state whose climate can develop ample tannin, go through a wonderful evolution as they age. He’ll tell you that he prefers at least five years on most of his reds, if not ten, largely because it takes time for the tannins to resolve. When his wines hit their target balance, they offer classic Washington flavors combinations and textures. I recently had an 8-year old Soos Creek and loved it.

The first thing to know about tannin is, well, what it is. Tannins are chemical compounds, and the term originates from leather tanning, as leather workers used them to preserve the leather. Tannins bind proteins together. The physical sensation we associate with tannins in our mouths when drinking a wine is the actual process of proteins being bound in real time.

Phenolic tannin. Credit: WineLand Media

The next thing to know it is that the term “tannin” encompasses two components: anthocyanin and phenolics. Anthocyanin is the color in the wine, and it’s the main focus for Richie at Rombauer because “it’s a very good indication of quality: the higher the color, the higher the potential quality.” Color is finite; there is only so much color in fruit and only that amount available can be extracted. Phenolics, of which there is usually higher quantities than anthocyanin, are chemical compounds, of which there are potentially hundreds of varieties.

Richie aims for full extraction of color. If he can hit that, then he and his team can build the desired tannin structure because there’s usually more phenolics than they need. Put another way, if they have really high anthocyanin then they can push the tannin structure without throwing the wine out of balance. However, if the anthocyanin is moderate and they try to push the tannin structure by ramping up phenolic extraction, they end up with a highly tannic wine that has a hole in the mid palate, something Richie and his fellow Aussies refer to as “donut wine” (lots of tannin around the sides and nothing in the middle). Shane, too, is focused on color. He describes one of his priorities as achieving good “color stabilization,” which is another term for the same thing: the bounding or conjugating of anthocyanin and phenolics into “complexes.”

Tannins, as David explained, “are very specific to each batch of grapes. Like everything else in winemaking there’s a lot of variability between varieties, vineyards, and even blocks within vineyards.” David is looking for great mouthfeel. His ideal tannins are the kind “that caress the mouth. It’s one of the best attributes of a wine, but hard to achieve. I’m looking for abundant but fine grained tannins, which create elegant wines.” These, as will be explained below, are long-chain tannins formed by the binding of anthocyanin and phenolics.

When speaking to a pinot noir producer, you enter a different tannin realm. Pinot’s tannins are very different than any other varietal because physiologically, the tannins and structure are unique. “You have skin tannins, your anthocyanins, and then you have seed tannins, and not a whole lot of other phenolics involved like you do with cabernet or the Bordeaux varietals,” Shane said. “This makes both tannin extraction and the mouth feel very different.” The differences in tannin that we experience in drinking pinot noir are unique tannin experiences when compared to other reds.

Credit: EnoViti

Anthocyanin is developed in the vineyard and lives in the skins of the berries (the term used to refer to the grapes). Richie looks at many things in trying to influence color accumulation in the skins. If the berries get too large, color gets diluted. Too many berries on the vine can lead to less color. Sun exposure is key: too much sun and the berries get sun burnt; not enough sun and they don’t develop much anthocyanin. “Think of anthocyanin as sun block,” Shane explained. “If you’re giving the berries less sun, they make less sun block.”

This makes canopy (the leaves) management critical. The act of picking leaves from the vines, called “leafing,” is part of this. In Shane’s vineyards, they begin leafing right after flowering and fruit set in most cases. This approach is suited for the cooler climate of Oregon where sufficiently warm sun, needed to develop anthocyanin, isn’t always plentiful. “More sun produces more and riper anthocaynins for us,” Shane noted.

Richie focuses on berry weight and size. Smaller berries tend to have higher anthocyanin levels. That said, Richie has his outliers. “I have a couple of vineyards that, on paper, should be terrible when you look at the numbers, but when you taste them, they’re really good and the numbers don’t match. I always say, you can graph it and draw your correlation line, but there are always outliers, and that’s why we taste.”

Shane expressed a strong desire to produced “balanced crops.” If there is too much fruit hanging, “you often get more green tannins, meaning seed, or short-chain, tannins.” Over the years the average crop of Willamette pinot noir has settled into the 2.5-3.5 tons per acre zone, “and when you hit that tonnage,” Shane says, “you’re ripening your seeds, and ripe seeds equal ripe tannins and you’re not extracting shorter tannins; you’re getting longer chain tannins and that’s your desired starting point” in achieving good texture and mouthfeel. “Balanced vines are going to give you ripe tannins and balanced wines.”

A common theme among these three winemakers is that they approach winemaking looking primarily at the structural elements of the wine, not flavors or aromas. Shane’s approach is to make wines “texturally” because texture shows through in the wine for a longer period of time than other elements and “is more of the wine itself then flavors or aromatics. Texture is the most stable part of the wine.” Therefore, when Shane extracts tannins, he’s doing it in the context of achieving that desirable texture.

Richie has been accused of making wine by numbers, and he admits that to a certain extent, he does. “All I’m doing is stacking the deck in my favor. It’s like counting cards – you’re working the probability to get a desired outcome. That’s all that we’re doing, and with fruit that’s $10,000 or more per ton, you want to make sure you nail it every time. In high end winemaking, you can’t screw it up one year and say, well, we’ll do it better next year. That doesn’t fly.”

Winemakers can’t rely on taste alone in the tannin context because of the presence of sugar during fermentation. “The reason we’re so interested in the numbers is when the wines are fermenting and you still have sugar, you can’t taste or feel tannin in your mouth. It’s all hidden by the sugar,” Richie told me. “So the only way to see if you’re heading in the right direction is to run analysis. You don’t know if you’ve gotten all the tannin out, you don’t know what the tannin level is when it’s at even three Brix. You can’t taste it. And if you keep pumping it over and you overshoot that mark, it’s too late. You can use strippers [like egg whites or gelatin] to lean the tannins, but you can’t just strip tannin without getting rid of stuff you want to keep. Fining agents are not as selective as they’re portrayed. The analysis is a good indicator of potential quality, though it doesn’t replace actually tasting either.”

David strives to balance alcohol, tannin, fruit, oak and acid. “This is largely a function of the grapes you get,” he says. In Washington, David believes the most impactful adjustment to make to find the sweet spot in the balance is tweaking sugar levels. “It matters a great deal because it determines the alcohol level, and I want a relatively low-alcohol wine.” For age worthy wines – read high(ish) tannin and high(ish) acid – alcohol is the sticking point because while tannins and acids soften with age, alcohol remains exactly the same its entire life. A wine with great tannin and acid at bottling will fall out of balance with time if the alcohol is too high.

Credit: Wine Folly

Fermentation is a key phase for tannin development, even though, as noted above, you can’t detect the tannins by taste, because, as David explains, “the higher the temperature the more tannin extraction you get. The longer the juice stays on the skins, the more extraction of tannin (up to a point). The tannins will start to soften as they get longer.” He starts his fermentations off at usually around 65 degrees and allows them to creep up slowly to the mid to upper-80s. This translates into fermentations usually lasting around 20 days, though they’ve gone as long as 30. He added that the shape and size of the fermenter matters as well in that it determines the juice to solids ratio as well as the flow, or interaction, of the juice with the solids.

Shane approaches fermentation with temperatures that are considered on the lower side for pinot noir. Whereas most are toping top out at around 86-90 degrees, Shane doesn’t go above 78-80 degrees. Temperatures matter for tannin extraction – warmer temperatures help to extract heavier tannins. Therefore, if he’s getting a higher extraction than desired, he will lower the temperature, and vice versa.

Punching down the cap. Credit: Willamettewines.com

Management of the cap, meaning all of the solid bits that float to the top during fermentation, also plays a big role because the cap is where the tannins – anthocyanin and phenolics alike – originate. The two most common ways to manage the cap are “pump overs,” which involves keeping the cap where it is while pumping the juice below it up and onto the cap, and “punch downs,” which refers to pushing the cap into the juice. The former adds more oxygen to the juice, which functions to elongate the chain of the tannins. As Shane describes it, short chain tannins are coarser drying tannins whereas longer chain tannins are “umami tannins and not as drying.” Shane uses pump overs early on to elongate the tannins as those are his preferred variety. Once fermentation is over, so too is grape-based tannin development.

Phenolics drive more of the textural element than anthocyanin. When there is an excess of phenolics, winemakers strive for high levels of bound anthocyanin and phenolics because it helps to reduce coarseness. I asked Richie if determining the chains by taste is as simple as, if the wine is coarse, it’s heavy on the short chain, and if it’s smooth, it’s heavy on the long chain. “More or less yes,” he said, adding that I was “basically correct, [but] when you start to look at the types of tannins and their interactions it becomes very complicated and our understanding is in its infancy. Thus is the art of winemaking.”

Untoasted wood chips can help in this department, as do additives like enological tannin. Richie has played around with these methods in trials, and while they’ve offered some interesting outcomes, he hasn’t felt like it’s boosted quality and hasn’t deployed it in production Rombauer. However, if using highly cropped, lower quality fruit, the use of chips or enological tannin can really help develop a wine of superior quality. “I’ve known people who do it really, really well,” Richie said. “And I’ve done it myself [at other wineries]. If you don’t understand how to use exogenous tannins correctly, you’re really limiting your ability to make quality wine. Especially in the cheaper bracket. At the higher end, you don’t need to do it.”

I asked him if it’s possible to pick up on the use of these tools in a wine by taste, and he questioned whether one could. “I’m not saying it’s impossible, but I don’t have the ability to do it and I don’t know of anyone who does. However, to make wines taste more palatable texturally and give them more palatable mouthfeels, especially in the lower price tier, their use is a sure way to improve your quality.” Dispelling any notion that it’s a New World thing, Richie explained that it’s very common in Europe, and referred to an unnamed friend in France who “is really well versed in how to use enological tannins and phenols to build wines to make them significantly better in that lower price bracket, and he’s really, really good at it. If I were making $10 wine, I’d be calling him to learn more.”

Measuring anthocyanin levels in the vineyard is challenging, and naturally Richie and his team have found that the most labor intensive way to measure gives them the best data. I promised not to spill the beans on this method, but after the explanation it’s understandable why those not using it are a step or two behind. These measurements, however, don’t necessarily mean anything because there is often a difference between the amount of anthocyanin in the vineyard and the amount that can be extracted in the winery. Determining the factors that drive that difference would be a holy grail in winemaking, and one that Richie is chasing in earnest. Richie does not believe that any of the theories about anthocyanin extraction hold up to scientific scrutiny, though he believes this is the direction high end red wine is going: “how you maximize color accumulation and color extraction drives wine quality.”

Credit: Wine Folly

How one extracts anthocyanin from the berries depends on the varietal. “You always hear about cold soaks with pinot noir, and that’s not something you really hear about with many other red varieties. Syrah, maybe. Some winemakers working with Bordeaux and Rhone varietals are doing cold soaks. Nebbiolo, too. But when it comes to red varietals, when you hear cold soak you think pinot,” Shane said. David is one of those doing cold soaks with Bordeaux varietals. During that process, both make no qualm about using appropriate levels of sulfur, which they find critical to tannin development because it helps to stabilize the anthocyanin complexes in both stages.

The goal as Shane explains it is to build stable anthocyanin-phenolic complexes by bringing as many together as possible to form the longest chains they can “because these are the good tasting tannins.” Oxygen, as explained in the paragraph above on cap management, is critical for this to occur. Most red varietals require doses of oxygen exposure for these chains to form and grow longer. If you’ve ever had a reductive syrah, for example, chances are it was not racked (a method for adding oxygen to the wine post-fermentation) because syrah requires a relatively high amount of oxygen to avoid reduction. In a reductive wine the tannin complexes are scavenging for limited or non-existent oxygen in the wine, which reduces the vibrancy of the wine’s aromas and flavors. This is why, when one aerates a reductive wine, it can snap out of its reductive state.

Pinot is unique among red varietals in that it has a naturally high anthocyanin-phenol ratio. Therefore, if it’s exposed to sufficient oxygen, it does a great job on its own of building beautifully tasting tannins. “Somehow,” Shane noted, “they figured this out over 1,000 years ago in Burgundy. If you start with great pinot fruit and age it in French oak, which breathes perfectly for the varietal, and don’t mess too much with it, you get great wine.” He continued, “once it’s in barrel, all you need is once-a-month topping and the wines won’t go reductive.”

When Shane gets his pinot harvest into the winery and destems, he’s aiming to maintain whole berries (he destems roughly 80% of his clusters) to allow for a longer cold soak. “Crushed grapes tend to ferment faster because, I think, it releases more nutrients [for the yeast to feast on].” Whole berry fermentation allows for maximum anthocyanin extraction while protecting the seeds longer before their harsher and more abundant tannins begin to enter the juice. “Pinot noir is a low tannin wine in general. Almost all your tannins are in your seeds, and it’s also a relatively low anthocyanin grape.” With that in mind, Shane does long cold soaks (~5 days for Gran Moraine and ~8-10 days for Zena Crown) to maximize anthocyanin extraction before fermentation “so you can really control tannin [phenolics] extraction during fermentation using punch downs, pumpovers and temperature, the principle being that seed tannins are highly extractable in an aqueous alcohol environment (alcohol dissolved in water), whereas you don’t need alcohol to extract anthocaynins.” Since there is no alcohol in the cold soak, there’s no risk in extracting phenolics while anthocyanin is seeping into the juice.

Richie describes the profile they seek at Rombauer as an “iron fist in a velvet glove,” which is driven by the color and phenolic binding. Wines cannot achieve a high level of binding unless there’s a lot of color already in the wine, which makes it the limiting factor in driving quality if you follow Richie’s logic. When Rombauer does in-house trials, they look at the free anthocyanin, bound anthocyanin and phenolics [a.k.a. complexes], and they find that more often than not, the wines with the highest bound anthocyanin are the ones they score the highest in double blind tastings.

Quality wine evolves with age, and to many palates it improves over time. I asked Richie about older wines and why the color loss during aging didn’t necessarily lead to losses of flavor and structure. He explained that bound color, which tastes good, is stable and resists oxidation and changes in pH. Unbound color that exists in wine is unstable, and as wine ages it’s the unbound color that drops out while the bound color remains. Therefore, a wine with a higher level of bound color is going to keep its color, and its desirable flavors, longer in the bottle.

Referring back to his holy grail of winemaking, Richie noted that “tannin is kind of like the black magic of winemaking at the moment, and not everyone understands it. A lot of high end wineries run [the data], but they don’t actually do anything with it because they don’t understand it. They run it because it’s the latest cool thing to do in winemaking. ‘What tannins do you have?’ It’s like, ‘what does it matter? What are you going to do with them?’ If you don’t know what you’re trying to achieve, the data is useless.” Shane doubled down on the difficulty of understanding tannins. “I took a whole graduate level course on tannin chemistry. It’s incredibly complicated and possibly the most difficult college course I took. I think it was called “The Biochemistry and Physiology of Horticultural Products” or something, and we still have open questions about tannins.”

Where our understanding of tannins goes from here is up to people like Richie, Shane and David who make it a focus of their winemaking. I do think it’s important, though, too, for consumers to educate themselves and maybe even do a bit of purchasing based on their tannin preferences. I would sure love more winemakers to focus on developing those long chain complexes.