It’s easy to imagine that the first wine was made by accident. Bunches of grapes were put in some sort of open vessel for storage and the weight of the grapes crushed some of the ones on the bottom. The juice from those grapes came in contact with the yeast on the skins and fermentation began, changing the sugar in the grape juice into alcohol.
Pretty much all fermentation of wine is some variant on this simple process. The grapes can be partly or totally crushed, the wine can sit on the skins during the entire fermentation process or the juice can be drained off and fermented separately. Different yeasts can be added, the temperature controlled (fermentation generates heat, which can kill the yeast, plus different temperatures produce different flavor compounds). Varying the shape of the container can change the product by requiring more or less mixing. But those people who, millennia ago, figured out how to make wine would probably still recognize today’s fermentation process.
So I was intrigued to learn more about a fermentation technique called carbonic maceration on my trip to the Languedoc in April. As I mentioned in my last post, some of the AOC wines in the Languedoc are made using carbonic maceration. I didn’t know much about it before other than that the yearly Beaujolais Nouveau wines are made using the technique. It struck me as interesting that wines as different as the soft, fruity Beaujolais Nouveau and the big wines I tasted in the Languedoc used this process, so I thought it was worth learning more about.
What I discovered is that although the method was standardized in France in the 1950s, it’s really that same ancient wine technique using intact grapes or grape clusters with one difference: a closed instead of an open container.
In addition to alcohol, fermentation produces carbon dioxide gas. Regular fermentation vessels, even if they have lids on them, still allow the carbon dioxide to vent. The normal atmospheric concentration of carbon dioxide — about 0.04% by volume — is maintained inside the tank. But with carbonic maceration the container is closed. The grapes in the bottom part of the vessel get crushed by the weight of those above them and begin to ferment normally, producing carbon dioxide. Instead of venting, the carbon dioxide stays inside the tank and surrounds the whole grapes. It’s only a small increase in carbon dioxide concentration, but it makes a huge difference.
What happens next is a particular set of chemical reactions that cause the grapes to ferment from the inside. The carbon dioxide diffuses into the grapes and creates alcohol from the sugar in the juice inside the berries with a boost from enzymes naturally found in the grapes, even without the yeast acting on it. Carbonic maceration stops when the alcohol concentration in the grapes reaches about two percent, usually in one to two weeks. (It’s also possible to skip the initial conventional fermentation of the grapes at the bottom and just inject carbon dioxide into the tank. In my reading I learned that wines made with that initial fermentation should strictly be called semi-carbonic maceration, but that seems a little picky, even for me.)
Of course, most wines have a lot more alcohol than two percent. So the grapes undergo regular fermentation afterward to consume some or all of the remaining sugar and create more alcohol. But even though the skins remain on the grapes during carbonic maceration, the wine produced has much less tannins (compounds that come from the grape skins) than wine made by conventional fermentation alone. Partly because of other reactions creating different flavors, the wines are also fruitier. Reducing the amount of astringency and bitterness that normally come from the tannins also enhances the fruitiness of the wine.
There are a couple of reasons why the wines end up with less tannins even though they spend significant time with the skins on. First, the grapes get physically softer from carbonic maceration, and it takes less pressure to release the juice. The skin doesn’t get as pulverized during pressing as it normally would. Less tearing means less of a chance for the tannins found in the outer layers of the skin to make their way into the liquid. So the wine will have less tannin unless it sits on the torn skins for a much longer time. Second, the juice inside the grapes is in contact with the inner layers of skin, which have much less (and possibly different) tannins than the outer layers. You can also see the difference carbonic maceration makes in the color of the wine — it’s a lot less intensely red than most conventionally-fermented wines. (Most of the color as well as the tannins is in the outer layers of the grape skin.)
It sounds like this would be a no-brainer to produce easy-drinking wines, but there’s a catch. Wines “softened” with carbonic maceration are not like more tannic wines “softened” with oak aging or slow exposure to oxygen in the bottle. They have a whole different flavor profile. And you can’t really age wines with 100% of the grapes fermented through carbonic maceration. You’ve probably noticed that your Beaujolais Nouveau — where 100% of the grapes undergo carbonic maceration — is fine when it’s actually “nouveau,” but once it’s more than a couple of months old it’s not even good for cooking. Finer wines that use some carbonic maceration keep the overall percentage of the technique down below 20% of the total, and often much less. This allows them to age more like conventionally-fermented wines.
Some winemakers in the Languedoc use carbonic maceration for part of their Carignan grapes, giving the Carignan/Grenache/Syrah/Mourvèdre blends a bit more light fruit flavor than they’d otherwise have. While the AOC rules allow it, the process has its critics. I have read about a few winemakers in the region who are convinced that even a small amount of carbonic maceration keeps Languedoc wine from achieving greatness over time Others, probably more of them, believe that judicious use of carbonic maceration can make tasty, interesting wines in a shorter time than they’d otherwise need.
As I mentioned before, I’m not sure where I come down on the issue. I thought the 2010 and 2011 reds had a kind of sameness to them even from different Languedoc appellations. I wondered if perhaps I was just sensitive to compounds that might be produced by carbonic maceration and they were obscuring other differences in the wines. In my reading this week, I discovered that people have reported a particular taste to wines made with carbonic maceration, but I don’t know if that “reduced” flavor (as they call it, referring to a low-oxygen environment) is what I was tasting or not.
I did notice, though, that the 2007 and 2008 versions of those same wines had great flavor and more individuality. So now I need someone to run an experiment for me: two blends from the same Languedoc vineyard made by the same winemaker, with the same percentage of grape varietals, one made with a little carbonic maceration and the other not. We’ll start tasting them a year after bottling and see what happens over time. Any takers out there? (I mean someone to make the wine — I know I can find plenty of volunteers to drink it with me 😉 )
Cy and I were in California last week and visited our friends Darrene and Chris, who moved to Sacramento last year. As always when we’re with them, we ate well. Cy and I hadn’t been to California at this time of year in a long time, and we were kind of surprised to see how much people don’t give the farm-to-table idea a second thought, it’s just sort of assumed. Here in DC the 300-mile limit for goods sold at the farmers’ markets gives us a good variety of produce from May through early October. The longer growing season in California and different climates means that a similar radius from Sacramento or San Francisco gives you an order of magnitude more options. Bigger farms and shorter travel distances to market can also mean lower prices than we have here. That plus greater availability make it easier to buy better stuff on impulse, rather than having to plan your week’s meals around a single market visit.
So it looked pretty effortless when Chris came home after work one evening and threw together a meal of grilled salmon served with grilled squash topped with a pistachio-mint pesto. (Effortless for Cy and me, anyway, since we sat on our butts drinking wine while Chris did the work.) This pesto just seems a little more summery than basil-based pestos, partly because there’s no cheese in it and the mint is a little brighter tasting. It’s a tasty topping or dipping sauce for nearly any vegetable, raw or cooked. It would be great tossed with pasta or served over fish. You could also take a couple of tablespoons of it and mix it with some more lemon juice and olive oil and make it a salad dressing.
It can be hard to find roasted, unsalted pistachios, but I nearly always see the salted ones in the grocery store. It’s easy to rinse them, then roast them in a 350-degree oven for about 10 minutes to dry them out, and almost all the salt is gone. If you do a big batch you can freeze the pistachios once they’re cooled and have them ready to use anytime.
The wine you serve usually depends on the protein in a meal and how it’s prepared. But if you’re looking for a light meal that’s mostly vegetables, try the pesto with Cave la Romaine Blanc Tradition ($10), a blend of Grenache Blanc, Clairette, and Bourboulenc. It’s refreshing and sets off the pistachio flavor nicely. You’ll eat and drink well, no matter where you are!
1/3 cup roasted, unsalted pistachios (see note)
1 cup fresh mint leaves
1 large clove garlic, smashed, peeled, and coarsely chopped
1 teaspoon finely-grated lemon zest
1-1/2 teaspoons fresh lemon juice
1/3 cup good quality extra-virgin olive oil
Salt and pepper
You can mix this by hand in a large mortar and pestle, but a mini food processor also works well. Start with the garlic and a pinch of salt, and whiz it for a few seconds. Add the mint leaves, the pistachios, lemon zest, juice, and about a tablespoon of the olive oil. Process until nicely ground up, stopping to scrape down the sides of the bowl. Add some pepper and the rest of the olive oil, and process until it’s all blended and pretty smooth. If it’s possible to stream in the oil while the processor’s running, it works a little better, but don’t worry if you can’t do it that way. Taste for salt, pepper, and lemon juice and serve. If you want to store it for a couple of days in the fridge, put it in a small bowl and press a piece of plastic wrap onto the surface to keep it from browning.
Note on pistachios: It can be hard to find roasted, unsalted pistachios, but I nearly always see the salted ones in the grocery store. It’s easy to rinse them, then roast them in a 350-degree oven for about 10 minutes to dry them out, and almost all the salt is gone. If you do a big batch you can freeze the pistachios once they’re cooled and have them ready to use anytime.