The problem with bagged wines

Using balled-up plastic wrap to ameliorate the funk of a corked bottle (because TCA adsorbs, or clings, to the cling wrap) is an old trick, but I’d hazard that our thoughts about wine and plastic didn’t go much further until the recent hullaballoo over BPA and the health risks it poses when it leaches out of packaging and into food. We’re newly aware, now, that plastics aren’t just neutral, inert, ignorable containers. The good news is that Scholle, the major manufacturer of the plastic bags inside box wine, asserts that their bags are BPA-free; more on that note here, a piece on wine safety I wrote for Palate Press.

But the wine safety coin has two sides: your safety, and the wine’s safety. Is the wine safe from the bag? “Scalping” is a known problem with plastics. Like people who can’t swim clinging onto the edge of a pool, hydrophobic (“water-fearing”) molecules decide that they like the plastic better than the nearly-all-water environment of the wine, and they hold on. With those molecules attached to the plastic instead of suspended in the wine, the wine’s flavor changes for the worse.

We know almost nothing about the specifics of what wine components end up attached to the plastic,** but several studies over the past few years have compared the composition of the same wine stored in different packaging systems for several months. Just out in the past few weeks is research showing that Vilana (a white varietal wine made in Crete, chosen because the researchers are from Crete) is perceptibly different, compared with the gold standard dark green glass bottle, after three months of bag-in-box storage. SO2 values were significantly lower after just a month in plastic, and low enough to signify a significant threat of white wine oxidation after two months. Titratable acidity increased significantly after two months, and a whole slew of volatile (aromatic) compounds decreased by a more or less significant degree.

Regrettably, these folks didn’t assess what effect those changes had, if any, on wine flavor; they only asked their tasters whether the bagged wine was different than the bottled wine (which it was) and not how it was different or whether it was more or less tasty.

Similar problems with bag-in-box Chardonnay were demonstrated by Hildegarde Heymann and her team at UC Davis last year, showing decreased volatiles and increased oxidation products with bagged wine, especially bagged wine stored at warm or hot temperatures. Individual wines are bound to be affected by bagging to different degrees: the most important flavor characteristics of Riesling will depend on a different set of molecules than those for Chardonnay or Vilana or Tempranillo. But it’s still safe to say that flavor scalping is an all-around problem for wines stored in plastic, and that bags leave wine dangerously susceptible to oxidation if left to sit around for a few months.

Most bag-in-box wine is purchased for immediate or near-immediate consumption, as is most wine in general in the United States. But, in every case, undesirable bag-related changes were accelerated by high temperatures. Between unrefrigerated shipping conditions and potentially careless in-store handling, I suspect that stores and wines with lower turn-over rates often don’t taste the way they should by the time they reach someone’s glass.

If we’re talking about the cheap stuff that goes into most boxed wine, and the (I’m going to be blunt) undiscriminating people who drink it, that’s inconsequential. But the push for better wine in “alternative” packaging (essentially all of which involves plastic, with the exception of refillable growlers) has been un-ignorable. This is great: solutions like bagged wine are generally more environmentally friendly, lower-cost, and super-sensible for someone (like me) who wants to have one glass of respectable wine a night (and who hasn’t yet sprung for a Coravin, which I’ll grant is the obvious and better solution). But the plastic system — or control over storage conditions, or preferably both — will have to improve before an educated consumer will want to entrust anything other than a casual backyard red to a plastic bag.

**I suspect that the companies who produce and sell bag-in-box wine actually have a lot of privately-generated data about wine-plastic interactions, but they’re not sharing.

New World Ingenuity, Interdisciplinarity, and New Zealand’s Sauvignon Blanc Programme

I’ve been reading James Halliday’s and Hugh Johnson’s lovely, rambling The Art and Science of Wine (Firefly, 2007), with something of the feeling that I’m sitting beside the old gentlemen’s fireplace listening to them hold forth. The book is short on citations and uneven on explanations, but full of two careers’ worth of wisdom. They describe without getting bogged down too much in the how or why of things, a good technique for teaching in a hand-waving, appreciative sort of way and for learning without paying too much notice to the reality that you’re being taught.

A theme — mostly tacit, but persistent — that sticks with the first few sections of the book is the difference in marketing and, therefore, winemaking strategies between the Old World (especially the classic French regions) and the New (especially Australia and New Zealand). Old World: make it and they will come. New World: no one knows who we are, so we’d better be distinctive and creative and different (and tasty). The socio-cultural-historical-economic factors driving that difference are too extensive to explain here and, besides, are largely a matter of common sense. And if it’s an oversimplification, it’s still largely true.

New Zealand has had to fight hard for a place in the global wine eye. Not only is the Kiwi wine industry young and from a remote location, their production is tiny. Yet they’ve unquestionably succeeded. We’ve all heard about Marlborough Sauvignon Blanc, and many if not most of us have heard about Marlborough and Central Otago Pinot Noir. New Zealand’s problem (okay, one of New Zealand’s problems) now is that they’ve played the region-grape association game too well. Kiwi Sauvignon Blanc can be too easy to stereotype. The industry seems especially concerned that their wine is too expensive, with cheaper Sauv Blanc from Chile and South Africa and elsewhere on the market, to keep being competitive without some kind of new consumer incentive.

So, the Kiwis are trying to teach their pony every trick in the book (and maybe invent a few new ones) in an effort called, creatively, the New Zealand Sauvignon Blanc Programme.

A partnership between essentially every major wine research institute in the country and a few major producers (notably Pernod Ricard), the Sauvignon Blanc Programme was first funded in 2004 and has a promise of continued funding through 2016. 2010-2016 is it’s second phase: “Sauvignon Blanc 2: ‘novel wine styles for new markets.'” Phase I largely served as information-gathering about Sauvignon Blanc-specific flavors and flavor production; phase II is aimed at optimizing and manipulating those flavors. The goal is to improve the quality of existing wine, but also to carve out new styles from the harmonious-but-homogenous* cat-piss-on-gooseberry  style for which New Zealand in general and Marlborough in particular has become world-famous.

The exemplary thing about this programme, in addition to it’s duration, is its interdisciplinarity. An effort to solve one problem — how to diversify Kiwi Sauvignon Blanc — is bringing together plant cell biologists and viticulturists and wine chemists and yeast geneticists and sensory scientists and cognitive scientists and assorted biotechnologists and industry folk — winemakers and growers and business and marketing people — all with different perspectives on how to solve that one problem. In the process, they’re creating solid new science, funding Masters and PhD students who will be important to the industry in a few years, and fueling market growth: good for research, good for industry.

Industry dollars are a main source of funding for wine research everywhere, but rarely is the collaboration this diverse or long-standing. The scope of SB1 and SB2 are fueling research far beyond just bringing a new and improved white wine to market. Here, the Kiwi homogeneity is serving them well: even if not everyone makes Sauvignon Blanc, the industry as a whole obviously rides on it. I wonder what would happen if other winemaking regions could identify one massive problem relevant to more or less everyone, focus their resources, and sponsor all of the region’s top researchers to help solve it.

I suspect that multiple different Sauvignon Blanc flavor profiles are going to be a hard sell to all but the most esoterically sophisticated Americans, though perhaps the more important UK market will be better educated enough to pay attention. We’ve already seen scientific publications from this project; we may just have to wait to judge the success of the wine.

Market pressures don’t always make for good science. But, sometimes, they do.

On Palate Press: A New Entry in the “Which Closure is Greener” Debate

My December column at Palate Press, the online wine magazine, is now up. I revisit an issue I covered in late 2011 — the relative environmental impact of natural corks versus screw caps — with new data from Nomacorc, the leading manufacturer of synthetic (plastic) cork-like closures.

Closure for closure (that is, if we ignore the question of waste as a result of wines made undrinkable by the failure of their closures), natural cork still comes out as the most environmentally friendly choice in nearly every respect. A bigger point is that closures are a very small part of the total environmental impact of a wine. (How small? Probably an unanswerable question, unless we’re calculating numbers for a specific wine.) That said, if you’re the kind of person who reuses her plastic wrap, it might be worth remembering that the neck of your wine bottle can contain something made from metal, something made from plastic, or something made from a tree that’s still standing and respiring in a Mediterranean cork forest.

Read the full article here.

S. cerevisiae: Friendly to us, but…

Saccharomyces cerevisiae is one of the friendliest microbes around. The good, old, familiar yeast used for (nearly all) bread, ale (lager yeast are different), (nearly all) wine, saké’s second (alcoholic) fermentation, and an improbable array of industrial applications: making CO2 to bubble into aquariums and keep subaquatic plants from suffocating and manufacturing insulin, for example. Heck, my favorite state even elected it as the official state microbe this past May, making Oregon the first – and only – state to have a patron yeast.**

The yeast so friendly to us, though, is a good deal more sinister to its peers.

Branco and colleagues, at the Laboratorório Nacional de Energia e Geologia in Portugal, have figured out that some S. cerevisiae strains release peptides that kill other types of yeast and bacteria found in the early stages of wine fermentations, including the love-it-or-hate-it Brettanomyces bruxellensis (responsible for barnyardy Burgundy and a whole lot of spoiled wine that tastes like old gym socks).

Microbiologists have also known for decades that some strains of S. cerevisiae are “killer yeast,” releasing peptides (very small proteins) that cause the death of other “killer sensitive” strains. Killer yeasts can be a cause of stuck fermentations: if your carefully selected yeast is killer sensitive, an accidental contaminant population of killer yeast could wipe it out, leaving only the less well-adapted accidental yeast unable to finish fermentation, and leaving residual sugar in a wine that was supposed to be dry. Brewers who want to play with wine yeast in ale recipes need to be careful, too, because the majority of wine yeasts release killer peptides and all ale yeasts are killer sensitive; mixing the two requires choosing a non-killer wine yeast. More recently, we’ve learned that some malolactic fermentation bacteria (like Oenococcus oeni) are also sensitive; a reason, perhaps, for some malolactic fermentations not kicking off as expected.

So we knew that already. But the new peptides that Branco and colleagues have identified are important for two reasons.

First, we’ve been operating under the general assumption that killer yeast will only kill other yeast (and maybe some of those malolactic bacteria). If that’s not true, we may have a new and improved explanation for why some microbes interact the way they do.

Second, if some S. cerevisiae make a peptide that will kill off undesirable or spoilage yeast, we could use it to our advantage. Produced in bulk, they could be added as a “natural” preservative against Brett and other nasties. Other yeast toxins have been used in similar ways.

S. cerevisiae always takes over wine fermentations, even when musts aren’t inoculated with commercial active dry yeast, and even though grapes in the vineyard play host to a large and diverse population of other yeasts and bacteria. We’ve generally assumed that S. cerevisiae takes over because it’s best able to withstand the rather noxious fermenting grape environment – high sugar, high acid, increasing amounts of alcohol (S. cerevisiae‘s high alcohol tolerance is especially significant) – and because it grows fast.

What this research calls to my mind are recent explorations into adding microorganisms other than S. cerevisiae to fermentations, not to carry the burden of sugar-to-yeast conversion, but to add flavor and complexity. New killer peptides may offer a welcome explanation for why some microbes work well with S. cerevisiae and others don’t. For at least some of those that don’t make it, maybe we need to change the cause of death from “suicide under high stress” to “murder.”


**Wisconsin made an attempt in 2010 to elect Lactococcis lactis, the workhorse bacteria for culturing cheddar and many other cheeses (not to mention lactic-fermented pickles, but those are more Seattle than Wisconsin), but the movement stalled in the Senate after being passed by the House. And Hawaii’s House made a movement to elect Flavobacterium akiainvivens (which doesn’t appear to be of any particular good to anyone, but was found on a rotting bush on O’ahu) in February but, again, it failed to clear the Senate. The official state microbe is evidently catching on, to which I give an earnest “Hooray!” if it means more popular awareness for how much bacteria and yeast contribute to our livelihoods. The marvelous Elio Schaechter thoughtfully collected crowd-sourced suggestions for some other states on the dedicated microbe blog Small Things Considered here