Chasing the mouse out of Anjou.

We took advantage of our recent visits to Anjou to talk to some winemakers about mousiness* and their ideas for preventing it.

* Mousiness is a microbiological off-flavour in wine, reminiscent of mouse smell and peanut taste, among other things. It is often only temporary and mainly affects wines with no or very little sulphur.

Like all winemakers who have decided to take the plunge and vinify as naturally as possible, those from Anjou are no exception to the rule and have been confronted with the appearance of mousiness in wine for about ten years. Most often it happens during bottling, where the wine is exposed to larger amounts of oxygen, which seems to benefit the problem. But sometimes it also shows up during ageing in the tank or barrel, which is a serious problem because the mouse now tends to make itself at home in the wine and takes up long-term residence in the bottle. Even though the mouse from bottling is a temporary problem and tends to disappear from the bottle after the wine has had a period of rest, the duration of this period is completely aleatory. It is not possible to say how long it will take for the mouse to find its way back once the bottle is opened, nor what period of bottle ripening can be expected to finally eliminate the mouse. But it is always good to know what we are getting into when we open a bottle, because for all of us who have been drinking natural wine for over a decade, it seems a long time since we carelessly saved an open bottle for later, without the threat of having to empty the wine down the sink in the coming hours or days.

The problem is even more serious when working in the wine trade and hospitality industry. Since we mainly want to introduce non-wine drinkers or lovers of conventional or industrial wines to the benefits of living wines, the mice problem is a real headache and does not exactly contribute to the democratisation of this type of winemaking. Imagine the facial expressions of a prospective customer who has not yet dealt with "natural wine" and to whom we explain that the bottle of red wine he has chosen is great but should be drunk within 2 hours because otherwise a mouse will move in. Mouse in the wine?! What the hack?? …

In France, some regions still seem to be somewhat spared from this problem, where the vineyards are located at high altitudes and the grapes are harvested with a relatively low PH, as a good acidity level seems to prevent the appearance of the mouse.

This mouse is difficult to catch, and since there is no clear scientific answer as to when and why it appears, each winery has to experiment with tricks for itself and its site to at least keep it at bay. Solutions that have to be continuously adapted, as differently constituted grapes are brought into the cellar with each vintage.
Like every time we visit winemakers, we used our visit to Anjou to talk about the issue of mousiness and to understand the different attempts to track down and avoid this annoying problem.

Jérôme Lambert, a proponent of sulphur-free winemaking, not only ages his wines in the bottle for one to two years before putting them on the market, but has also decided to bottle them only when the outside temperature is above 20 degrees, because for him, the wines are more susceptible to oxygenation and thus to the appearance of mousiness when they are cold, whereas at a higher ambient temperature they are naturally protected from this oxygenation and thus from future problems. We will have to be patient to find out if this measure is sufficient, because at the moment his 2020 Chenins have not yet processed their sugars. No problem for his 2018s, a great vintage, in his opinion his best, which we will receive this autumn.

Kenji and Mai Hodgson, who also advocate sulphur-free wine, take a different approach. After a visit to the great Alsatian winemaker Bruno Schueller, from whom they also brought back a wooden barrel (yay!), they decided not to fill their barrels to 100%, like Bruno, who always fills his barrels according to the harvest, be it for his white or his red wines, so that he can sometimes leave a barrel half empty. The idea is to get the wines used to oxygen from the time of maturation, in the hope that the wines will then better withstand the inevitable oxygenation at bottling. 2020 seems to be a much more balanced vintage than the 19 or 18. The Chenins we have tasted from the barriques are very promising, and the omission of refilling these, at the moment, has not brought with it the oxidative notes that can be typical of this type of ageing. We keep our fingers crossed for the further development, because we were very enthusiastic about what we were allowed to taste.

Of course, it is impossible to discuss the problem of mousse in wine without talking about sulphur. Many winemakers decide to add homeopathic doses of sulphur at bottling to stabilise the wines and ensure that they do not have this problem. As a consumer of natural wine since the mid-90s, I don't care about the sulphur as long as I don't smell it. I have been lucky enough to taste the same wine with and without sulphur a few times, because some importers ask the wineries to add some sulphur to their orders if the transport is very long, for example, and each time I have blindly preferred the unsulphured bottle. But without this opportunity to compare, my taste tolerance to sulphur is my only criterion when choosing bottles. For me, sulphur should remain a problem of the winemaker:s, most of them do not do it for pleasure, but with an eye on the consumer who should enjoy an immaculate bottle. Some act according to their taste, being very sensitive to certain typical faults of natural wine, such as volatile acids, brettanomyces or mice. Others out of a lack of confidence when they are just entering the trade, still others use sulphur when they feel compelled to do so, only with certain vintages, the particularly difficult ones. Because for all their desire to produce in the most respectful way, it should not be forgotten that this is also their personal investment and that many of them cannot afford, for economic reasons, to lose part of their production because a barrel begins to show defects that could affect it for good. And mousiness is only one of the many circumstances that winemakers are constantly confronted with as soon as they have opted for natural and sustainable winemaking.

Despite our preference for sulphur-free wines, it would not occur to us to boycott the wines of a winery that has been forced to use sulphur just to continue to make a living from them, preferring to offer a wine without fault, while many others will take advantage of the tension and tolerance of the market, where demand is greater than supply, to market wines that are clearly not ready to drink, but which bear the mark that they have been produced without the addition of sulphur.

For almost all the winegrowers we met in France, sulphur is added either at the end of the process, at bottling, or to put out the fire, so to speak, where a problem becomes apparent. In Italy, for example, many winemakers add sulphur at the beginning of fermentation because fermentation "eats" the sulphur, which is then no longer detectable in the analysis, because here it is more common that wine sulphurised at the end of the process no longer really corresponds to the designation natural wine.

This is in line with the path taken by Jean-Marie Brousset of Domaine La Vinoterie. Jean-Marie managed the Roches Sèches vineyard together with Julien Delrieu and Thibault Ducleux from 2010 to 2016. Since then, he has taken care of about 4 hectares of vineyards. To avoid mice or other problems in the wines, Jean-Marie prefers to sulfurise right at the beginning of fermentation, as in Italy, so that a good selection of indigenous yeasts prevails and bacteria cannot colonise. He prepares a "pied de cuve" (the equivalent of a sourdough starter in winemaking) in a "dame jeanne" (bulbous glass vessel holding about 40 L), doses 2g/HL and pours it into the first fermentation tank, from which he takes another "pied de cuve" to add it again to the second fermentation tank, and so on. In total he will have used 2g of sulphur for about 130 HL, which is comparatively insignificant. After that, none is used any more, the fermentations will proceed calmly, and the sulphur will no longer be detectable in the final analyses, nor will it be detectable to our palate in any of the vintages we have tasted and which we hold in high esteem.

These are three examples among many others that show the problems the winegrowers have and how seriously they take this problem, because as long as the appearance of the mouse remains a mystery, it has not stopped playing hide and seek with the producers and consumers. Climate change and rising temperatures, which tend to increase the PH of wines, are clearly playing into the mouse's paws and making the already hard work of wineries, which have to cope with visibly more chaotic seasons, even more complex. We plead for more understanding and tolerance towards the level-headed winegrowers and their various solutions to be able to offer us the most wholesome, animating wines in the long term. We should thank them for all this work by doing one of the most pleasant things in the world, drinking a glass of these very wines.