Tackling wine microbes with (or without) sulphur dioxide
· By Bernard Mocke
Whenever the topic of wine comes up, and the discussion continues longer than it takes to uncork a bottle of the good stuff, sniffing a cork suspiciously, or say ‘hold my wine’, the conversation will invariably gravitate towards what many consider the wine capital of the world.
Not quite a natural disaster, but close
Not to put too fine a point on it, I firmly believe that France, and more specifically Bordeaux with its 65 appellations and more than 7,000 châteaux spanning hundreds of thousands of acres, is the wine capital of the world. And this is why recent news about the French government moving to spend €200 million to destroy 80 million gallons of excess wine utterly shocked me (read more here).
What can we do about this vinous loss? Other than cracking a lame joke starting with ‘I know this guy …’ and which then delivers a punchline based on traveling to France to drink a fair portion of said doomed wine, nothing much. Which leads me to my next question. How can wine be protected from nasty microbes? Well, happily there is a lot that can be done about this.
Sulphur dioxide is so yesterday
The effect of SO2 on spoilage yeasts and bacteria (and apparently some sensitive humans) is well documented, so let’s look at three of Laffort’s biocontrol products instead. MICROControl® consists of chitosan and inactivated yeasts, is suitable for the overall reduction of microbial load, and can be applied post-AF. There is also a positive effect on clarification, and if you didn’t catch the hint earlier, this product and the two following ones to be mentioned, can all be used in a reduced SO2 vinification strategy.
Like its name suggests, BACTIControl® is focused on the control of lactic acid bacteria (Gram-positive cocci or rods for the more technically inclined). Its formulation of chitosan and enzymes (lysozyme, pectinase, and ß-glucanase) enables it to slow down or even stop MLF when used pre- or post-AF on white, rosé and red juice or wine. Once again, wine clarification and filtration is aided with this product.
Sidestepping the Brettanomyces crisis
OENOBrett®, a fan favourite which has ‘NO’ in its name (do you get it?), is next. It also has ‘Brett’ in its name. If you haven’t figured it out yet, this product’s formulation of chitosan and enzymes (pectinase and glucanase) makes it a highly effective tool against Brettanomyces spoilage. Lysed yeasts are rapidly settled out of suspension, and I should also point out that this product is of non-animal origin and allergen free. Note that it should only be applied after both AF and MLF are complete. Unless you like stuck or sluggish fermentations, of course.
As an aside, you might be aware of it that there are a lot of conflicting paradigms on quality and the presence of Brettanomyces species in wine. I’m not going to open that can of worms in this blog, but in the spirit of knowledge is power, consider reading the booklet I wrote for the Stellenbosch University titled ‘Brettanomyces – resilient super villain or misunderstood misfit’ (click on title to access booklet).
Bioprotection the Laffort way
One cannot talk about a low SO2 vinification strategy without mentioning ZYMAFLORE® EGIDETDMP and ZYMAFORE® KHIOMP. Both products respectively colonise either equipment or must and grapes (at low temperatures), thereby limiting the predominance of undesirable microbes. As a bonus, ZYMAFORE® KHIOMP has a high capacity to consume oxygen, which becomes a factor during low temperature pre-fermentative phases. So, we’ve got antimicrobial and anti-oxidant activity – not bad for a couple of selected wild yeast strains.
One last product worth a brief mention is FUMARICtrl®. This organic acid can be added to wine after AF to inhibit or stop MLF for weeks on end. Malic acid can therefore be preserved (resulting in a fresher aroma profile) and the use of this acid can form part of a strategy to lower SO2 use in wine.
While using our products certainly won’t protect your wine from economical downturns and demand disasters, they do a great job at keeping unwanted microbes in check. And speaking of disasters, I cannot let this chance go by without saying something about the imminent Rugby World Cup. If, and only if, South Africa doesn’t win it this time around, I sincerely hope that France does.
Vive la France!
