When a wine is salty, and why it shouldn’t be

Salty is not a common wine descriptor. That it’s also not a positive one probably goes without saying. As a consumer, it’s also not a fault you’re likely to fret over (I don’t think I can recall ever hearing anyone say something like “Hey, Sarah, does this wine taste salty to you?”) But the fact that wine-producing countries have (widely varying) legal maximums for sodium chloride in wine should tell you something. Salinity is a concern in dry locations when frequent irrigation increases soil salinity, which increases wine salinity, which may add one more to the list of western American winemakers’ concerns. Soil composition often doesn’t translate in the way you’d expect into grape composition; salt is, unfortunately, an exception.

An article in the American Journal of Enology and Viticulture last year mentions Australian growers’ and winemakers’ experience that grapes that taste salty may clock in under the legal sodium chloride limit and vice-versa. Law or no law, obviously no one wants “salty” to show up in their product’s tasting notes. The article reported on an effort to quantify when wine saltiness kicked in and how best to measure it. Most of the non-sodium chloride salts that show up in wine – potassium chloride is notable – register as bitter more than salty. Sodium chloride registers as salty, obviously, but also appears to convey soapy sensations. They were interested, then, both in how much salt it took for a taster to call a wine salty and in the negative impacts of defined amounts of salt on wine flavor.

Their cadre of tasters – enology students at the University of Adelaide with some specialized tasting experience – were able to first identify saltiness in Australian Shiraz and unoaked Chardonnay at .36 to 1.76 g/L with a median of .8 g/L and a lot of individual variation (values were lower for the white wine, higher for the red). The Australian legal maximum of .606 g/L, then, means that some of these folk may sometimes encounter a salty wine; the Swiss limit of .06 g/L, on the converse, seems unwarranted at least in terms of sensory concerns. The researchers also spiked the Chardonnay with several concentrations of NaCl and asked a smaller group of specially trained students to rate their sensory qualities. Those experiments confirmed that at .5 and 1 g/L, added salt dampened perceptions of fruit and added a salty flavor and soapy mouthfeel.

To the Australian researchers, the utility of their findings was in recommending that Australian growers could probably rely on their (quite possibly a bit more sensitive than average) taste perceptions to gauge grape saltiness in the field, in terms of acceptability for the Australian market, but not for meeting more stringent international guidelines. They didn’t comment on the implications of their findings for the reasonableness of those guidelines, though perhaps they go without saying. It does seem plausible that saltiness perception thresholds might vary among people of different nations accustomed to different diets, though this study’s Australian-based results were about on par with previous studies including a few conducted in Japan.

One other interesting implication, for household use. Obsessive molecular gastronomist Nathan Myrhvold has recommended that people try salting their wine as they would salt any other food. This is the same gentleman who suggests that a blender is an efficient tool for oxygenating wine, a more aggressive version of “letting it breathe” in a decanter. Myrhvold suggests a tiny pinch per glass. If one teaspoon of salt weighs about six grams, then 1/10th teaspoon per liter of wine amounts to the Australian limit of .6 g/L. A standard glass of wine is about 150mL. In other words, any realistic pinch will send your glass over the technically established edge. But it’s worth noting that Myrhvold is recommending this as a tactic to make a wine taste more savory.

I tried this with an exceptionally ordinary glass of Australian shiraz. The salt did, indeed, make the wine taste more savory. Frankly, that was neither difficult nor especially unwelcome for something that started off as a bit of a fruit bomb. But – and keep in mind that I was not tasting blind – the potential for that to be a benefit was outweighed by the kind of soapiness you get from having added a bit too much baking soda to your biscuits. In this wine, where the fruit was pretty much what it had going for it, I wouldn’t do it again, but I’m interested to see what happens with the next glass of reasonably lively Chardonnay I come across.

For producers in California, Washington, and other devastatingly dry locales, unfortunately, adding salt isn’t going to be that kind of easy option.

Wine’s genetic diversity: Thank goodness we’re not coffee

Wine has a diversity issue. Wine actually has several diversity issues, but I’m not prepared to deal with the massive and significant question of non-white non-male winemakers (today). The much easier diversity question is about the wine grapes themselves. And even though it’s an issue, and one that’s been rightfully earning more press of late, wine grapes have the potential to be a good deal better off than most crops. The problem is of our own making, and we should be able to unmake it.

Arabica coffee varieties, according to a recent genetic survey, share 98.8% of their genes in common. That’s an estimate made by sampling both wild and cultivated plants (781 sequences in total) from around the world. So, even if coffee breeders try their darndest to increase the diversity of cultivated coffee plants – which they are, because genetic diversity means better resilience against threats like infectious diseases and climate change – they only have so much room to work. The survey found that wild plants were more genetically diverse than cultivated ones. The breeding stock can be improved. But compare coffee to maize, for which something like 30% of the genome varies across all of the plants on the planet, and there’s not that much room.

Wine grapes are like maize, not like coffee. Both maize and Vitis are, in fact, extraordinarily diverse. No shortage of room here. What’s most curious for wine grapes, though, is that the difference between the genetic diversity of wild and cultivated vines isn’t that great. When humans domesticate a species, we create a genetic “bottleneck” (Nature has a nice image here), reducing genetic variability in the new crop. For wine grapes, the bottleneck was “weak;” the reduction wasn’t that dramatic. (Coffee, by the way, suffered a very severe bottleneck.) And earlier this year, a genetic survey of wild and cultivated grapevines in the Republic of Georgia, where grapes were first domesticated to the best of our knowledge, still found plenty of diversity in wild grapevines that doesn’t overlap with cultivated varieties and which have yet to be explored.

Unlike coffee, the real problem with wine grapes isn’t that the genetic diversity isn’t available, in wild or even in cultivated plants. The problem is that we’ve artificially selected for an incredibly narrow set of vines, over and over again, through clonal selection to replicate what we think is the best of the best. To recapture the genetic diversity that might help wine combat disease and changing climates and whatever else the next century or three throws our way, we need to undo the relatively recent work of the modern wine world.

The numerous research teams working around the world on the grape diversity issue have a great big spectrum of possibility out in front of them. That’s a good reason to be hopeful. And to be sorry for the coffee guys.

Empirical evidence: organic/biodynamic vit = more textured wines

A six-year comparison of organic, biodynamic, and “low-input” and “high-input” viticulture (three years of conversion, three of maintenance) recently came to fruition in South Australia, courtesy of researchers at the University of Adelaide. The full report is freely available here (and three cheers for research freely shared). It’s 73 pages long, but the conclusions are fairly simple. The most worthwhile among them: in blind trials, experienced wine professionals rated the organic and biodynamic wines more interesting than the conventional versions.

  • Soil health (nitrogen, phosphorus, organic carbon, microbe mass) was most strongly improved by compost, not by any particular management system. All four systems were tested with and without compost.
  • Compost had the single most dramatic positive effect on soil health, no matter the underlying management system.
  • Management system had no consistent effect on vine growth, berry weight, or berry composition.
  • Low-input, organic, and biodynamic alternatives yielded at 91%, 79%, and 70%, respectively, of the high-input condition.
  • Organic and biodynamic wines were more “textural, rich, vibrant, and spicy” than their conventional counterparts. (pH, TA, and color held constant; high-input wines were a bit higher in alcohol.)

Improved soil health with organic/biodynamic management has been demonstrated numerous times over, and so have the benefits of compost. This study was unusual in making compost a separate variable, showing that both organics/biodynamics and compost, separately, were beneficial. The upside here is the attitude, across the study, that conventional growers can benefit from organic techniques even without undertaking a full-on organic conversion.

The downside is that the “organic” and “biodynamic” management used in the comparison are weak compared with what many committed non-conventional growers undertake. How can you practice biodynamics without compost? “Biodynamic” here seems to have meant nothing more than adding the core preparations 500 and 501, a far, far cry from anything Demeter would certify as honest biodynamics. Even the organic system is pretty bare bones: weed control with mowing and cultivation instead of herbicides; no insecticides or pesticides other than copper. (The low-input condition pulled back on the insecticides and some of the pesticides.)

Talking about those lower yields, the researchers make an important point. Very little research has been done on organic or biodynamic cultivation methods. We could develop better techniques within those systems and preserve environment and fruit quality while improving yields. Many organic/biodynamic growers have surely worked out such techniques on a local scale, which leaves a role for scientists to listen to what they’re doing, identify why it works and how/whether it can be generalized more broadly. Some environmentally conscious wine people are happy to pour their big pharma money (or whatever it might be) into projects they believe in with no thought for financial return, but most are trying to support their families as well as their values. Sharing successful organic/biodynamic techniques — say, for weed management, which was the biggest issue in this study — developing them scientifically, and stamping them with a scientific seal of approval so that they’re not dismissed as just those quacky organic people, will help conventional growers improve their weed management tactics, too. Likely, too, with economic benefits you can appreciate even if you honestly don’t care about trashing the environment for short-term gains.

The researchers should have made another point about those yields. Are the high-input yields a reasonable benchmark? Should we buy short-term gains with long-term environmental and social damage? If your business isn’t “sustainable” without using chemical warfare to eke every last grape out of the earth, then perhaps you need to reconsider your business practices in other areas. It comes back to the old resurrecting dinosaurs argument. Just because we have the technology to do something doesn’t mean we should. The wine might even be more interesting.