A BUG'S LIFE
By far the three largest employers in New Zealand are the baking industry, the brewers and the wine makers. Admittedly they don't pay all their workers minimum wage, but even the smallest winery takes on an extra hundred trillion or so workers each vintage. They're yeasts.
Now most yeasts at bakeries, at breweries and at wineries come out of a packet. But each industry has groups of artisans who like to go wild: sourdough breads and wild ferments are the mark of those who treasure complexity and are prepared to live a little dangerously for it.
I know only a little about baking and nothing about brewing (go to www.wildyeastblog to learn about the baking side of this), but I suspect that the same principles apply. And the biggest principle is that the whole affair is an exercise in ignorance. If we ferment wild, we simply don't know what we are letting live in our wine. You can't interview candidates and essentially you are letting anything smaller than a ferret have a look-in.
Now there are two different aspects to this. The first is the early stage of ferments, when a wild ferment will have a lot of bugs other than saccharomyces joining in the party. Leading the dancing will probably be kloeckera, but you can expect to find bugs from the candida and pichia family, and all sorts of other malcontents. Some of these are spoilage yeasts which left to their own devices can ruin the wine. But after a few days, the saccharomyces should overwhelm the enemy having allowed them to contribute a subtle complexing factor to the wine without spoiling it. It can get scarier than that as well. George Fistonich at Villa Maria recently told me how, on occasion, trucks have been delayed carrying must up from Marlborough to the Auckland winery. On arrival they unload a Pallecon container which is inflated like a deranged moon-hopper leaving the winery staff drawing lots for who will risk life and limb defusing the wild yeast bomb!
The more interesting aspect is the saccharomyces. These may not have been bought in a box, but are they really wild? Maybe they just drifted down from the winery up the road who use commercial strains?
Now we know that different strains of saccharomyces create different flavours in wine, which is why all the yeast salesmen so enthusiastically ply their wares. So do truly local varieties exist and are their flavour profiles a legitimate, even an integral part of a wines terroir? This has been debated for some time, but now we have some serious research giving us some surprising results.
First how do you tell if yeasts are wild? Do they have some sort of test for their manners? Perhaps microscopes can reveal unkempt hairdos, tiny tattoos or other signs of a feral upbringing. How would one grade such signs? Perhaps we could create a unit of wildness: let us call it the Millicouth. Yeasts of less than 250 Millicouths are entitled to be labelled wild. Actually a lot of people reject the term wild, preferring the less prejudicial indigenous , but this implies some political consequences. Do we need particular cultural sensitivities here? Do special rights, traditional customs attach to indigenous yeasts which perhaps we need to preserve and cherish?
A lot of questions to which we now have answers. Kumeu River is one of a number of family of twelve wineries who walk on the wild side (all the family members use wild ferments to some degree or another). So researchers kidnapped yeasts during ferments then interrogated them as to their upbringing (this is not done by use of bright lights and threats, but by dismantling their DNA and studying it in considerable detail). We are thrilled to report the following conclusions: of the 88 sub varieties of Saccharomyces isolated, none were of commercial parentage. The bulk of them were definitely of Kiwi origin (perhaps they wear tiny black jerseys?) and not international interlopers. It would also appear highly likely that many of the sub varieties are exclusive to this one winery. Similar, but distinctly different, populations can be found in other winery's vineyards a few kilometers away, showing that these strains do come from the land and they are specific to very small areas. There was one large source of non-native yeasts and these were found in the French oak barrels used for fermenting and elevage. It would appear that these yeasts originate in the oak forests of France and not from the cooperage itself.
So, those who take a walk on the wild side in New Zealand do indeed have a unique microbial terroir, that is distinct down to vineyard and winery level. Right now at Felton Road, we are awaiting news of analysis of our own yeast populations. Like Kumeu, all our ferments are wild; the Kumeu winery is a lot older than ours, one of New Zealand's oldest, and it used to be a goat shed which has to be a big benefit in building microbial complexity, so perhaps we will see a smaller and simpler population? This all implies considerations we need to make in winery and vineyard practice. While hygene is always of critical importance, an attempt to be sterile might have consequences close to genocide. Hygene and sterility are very different things. Then there is the question of fungicides in the vineyard. To what extent does this damage a vital part of terroir? Just a couple of the many things for us to ponder as we absorb this latest piece in the jigsaw.