Thursday, 20 July 2017 11:44

Fermentation in the vines

Written by  Tessa Nicholson
Hand picked grapes are delivered straight to the outdoor fermenter. Hand picked grapes are delivered straight to the outdoor fermenter.

Dominic Maxwell, (Greystone Wine’s winemaker) has one goal - to make Pinot Noir that truly expresses its site.

That goal has led him down an unusual path, as Tessa Nicholson discovered. He is fermenting some of his Pinot outside in the vineyard, alongside the vines the fruit grew on.

You may think he is a bit crazy, and Maxwell admits there were plenty of sceptics when he came up with the idea four years ago.

But the experiment has proved so successful, that this year, the company will ferment 10 tonnes of fruit in the vineyard.

While he is a longtime advocate of wild ferments, a few years back he began to question whether these were influenced by conditions within the winery. Was the indigenous yeast that came in with the fruit, being affected by the yeast from other batches, or yeast found within the winery itself?

“I wanted to know if my wild ferments were truly indigenous or as a result of the vineyard. What was the effect of moving fruit away from its exact place of origin to ferment?”

He began to delve a little deeper, in his search for authenticity. That included stripping back where he could on additives and the use of toasty oak. The next step saw Maxwell focusing on the fermentation stage.

“The foundations of the fruit are built on during fermentation, so the character building phase at this stage is huge,” he says. “The microbial life in the fermentation is therefore crucial.”

It became apparent to him, that all influences outside of the fruit and the site where the fruit was grown, had to be removed. Which meant fermentation had to take place in the vineyard, alongside the exact vines the fruit came from.

“We are operating organically and with our increased awareness of microbial complexity, we felt there was no reason why this couldn’t work,” he says.

There was no one for him to garner advice from, as he was unaware of anyone else using vineyard fermenters. There were also issues that kept being raised. What about flies, bees and birds? What about sprayers? What about climatic changes and other weather related issues?

“All these questions popped up but they seemed to be able to be answered quite easily,” Maxwell says. “And the more I answered them, the more enthusiastic I got about just giving it a go.”

He said birds and insects are as much an issue in a winery as they are outside. Tractors and sprays are not in use at that time of the year, so no problem there. And temperature control – well fermentation will happen outside – it just may take a little longer in the open than it does in the winery. But that adds to the authenticity of the end product.

Fermenter wise, Maxwell has trialed a variety. Barrels and puncheons with their heads taken out, one tonne and two tonne sized plastic fermenters.

“The size that seems to work quite well, is something that is not too big that it gets really hot, but not too small that it struggles to warm up. We have settled on 1.2 tonne to 1.5 tonne plastic fermenters.”

The fermenter has a lid that can cover the fruit and juice, but once the lid is removed, there is a breathable cover that protects everything inside. It was 2012 when the first vineyard ferment was undertaken – a particularly cold year.

“We waited for the ferment to start and wait we did. We began to think it was going to be a spring ferment, it took such a long time. It was a 12-day cold soak. Fermentation started slowly and it was cool at that stage of the vintage and the fermenter was at one of our higher elevations.

“But we started to witness one of the positive surprises of the fermentations – the heightened influence of the vintage weather. With the fermenter in the elements, it was far more sensitive to the outside temperature.

“We really love that aspect, as I truly believe it extends the seasonal influence beyond the picking date, with the fermenter clearly in tune and connected to the vintage weather.”

Maxwell admits he hadn’t really thought about that aspect, until it actually occurred.

“I was quite naive about it in some ways. I had just been thinking about the vineyard yeast, not the influence of weather. But this allows not only the fruit to speak, but also the season to speak through in the wine.”

To determine if the vineyard fermenter was creating something different, Maxwell made a control wine. Fruit from the same block, picked on the same day, was taken back to the winery, and after fermentation and aging, the two were compared. Chemical analysis was undertaken and there was a noticeable difference in alcohol levels, with the vineyard fermenter being half a percent lower than the winery made wine. That has been a consistent finding in every year since.

“It wasn’t something that we had contemplated, but with increased exposure, higher evaporation potential, it sort of made sense. While this isn’t a game changer, it is definitely a positive aspect.”

As for how the wines stacked up in terms of aroma, flavour and texture - Maxwell is excited.

“Once we tasted the wine, it moved to a whole new level. There were no preconceived ideas as to how the wine might turn out, although admittedly we were keen to see some differences. We wanted to hear the vineyard singing clearly.

“There is a more savoury nature as far as aroma and flavour goes in the vineyard fermented. There is a difference on the palate as well. In the winery made wine, it is more tightly bound. In the vineyard, it seems to be quite a harmonious structure. I am still pondering why that is.”

As with all wine, season influences the end product. As Maxwell says, in some years the wine can be very dark and showing obvious strength. In others it can be light with subtlety and finer bones.

“In a sense, we notice those seasonal differences are amplified in the vineyard fermentations.”

Up until 2016, all the vineyard fermentations were used as components of Greystone Pinot Noir. But last year, some barrels were kept aside and for the first time, the wine will be released as a stand-alone. Maxwell strongly believes, these wines show a purity and harmonious sense of place. So much so that this year he has placed six 1.5 tonne fermenters out among the vines. The major portion will be used as a component in the Greystone Pinot Noir, while the rest will be marketed as Greystone Vineyard Fermented Pinot.

The interest garnered by his trials was obvious at Pinot Noir 2017. A large number of winemakers were keen to try the wine, and Maxwell is hopeful a number will undertake trials of their own.

“It will be great to see how it works for them and I would love to know who does try it, so we can maybe get a collective together to discuss and learn more.”


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