Winter, moose-braai and yeast cells   29 May 2007

Martin Moore takes his wines to the world and reflects further on 'wild yeast' in winemaking

Winter is setting in with a vengeance - and what vengeance! - and [at time of writing, sunny weather returned soon after] the barometer regularly hovers around 15ºC during daylight hours (that’s quite chilly for us in the Cape!). The leaves in the vineyards are turning brown as the sap drains back into the roots and the vines prepare themselves for their annual slumber. Seasonal cold fronts now regularly move across the southern part of the country bringing with them copious rain, as they did again a weekend or so ago.

I have just returned from Canada - Toronto, to be precise - where by contrast they have had just the most glorious warm weather compared to the icy temperatures they are used to. This warm spell had them quite excited, and one asked me over a glass of wine and not without a certain pride, how this compared with the South African climate. He was somewhat taken aback when I said it was more or less what our winter was like – the other eight months were a lot warmer. So taken aback was he, in fact, that in frustration he started banging his head on the counter!

The purpose of our visit was, as you would expect, to promote Durbanville Hills wines. This was done through wine and food pairings in some of the foremost restaurants in the city like Jamie Kennedy’s and Prego. In the latter the chef came up with the most astounding pairing of a pepper and strawberry risotto with our Shiraz – and which turned out to be the most wonderful combination!

Our hard-working PR people in Canada must have whispered to the local TV networks that I have a passion for food, for we had hardly landed back in Cape Town when there was an e-mail to say Canada AM had confirmed I was to appear live on national TV on 12 June. Doing what? You’ve guessed it, a South African “braai” or barbeque with a wine pairing – but using ingredients available in Canada. No gemsbuck steaks but moose cutlets, so to speak. Thank goodness I will have two days before the recording to find the right ingredients.

Homegrown yeast strains
My comments [in the March newsletter] on the use of ambient (also read wild) and cultured yeast strains solicited quite a lot of correspondence from readers. I hope I didn’t imply that you cannot make excellent, complex wines using ambient yeast. What I did say, was that ambient yeast is unpredictable and will often not see through a fermentation – I have experimented quite widely with them – and that unless you have a cellar dedicated to the use of ambient yeast, you will find that your wild yeast is soon dominated by cultured yeasts in any cellar in which both types are used. (Yeast cells escape from the tank into the air with the carbon dioxide during fermentation and end up in adjoining ones.)

One reader slyly asked whether I did not think that ambient yeasts better reflected “the sense of place” of a wine than ones “developed from those in Italy or France”? A good point, but then all the cultured yeasts we use at Durbanville Hills are indigenous yeasts that have been isolated and propagated either by the Agricultural Research Council at Nietvoorbij or by the University of Stellenbosch.

One of the university’s yeast strains is a typical illustration of why I choose specific yeasts for specific cultivars and wine styles. VIN 13 is a powerful tool in turning all the sugar in the juice to alcohol to create a perfectly dry wine. Normally, when you want to retain some sugar in a wine, you substantially lower the temperature of the tank thereby killing off the yeast cells and stopping fermentation. Not so with V 13. It’s impervious to low temperatures, so whether you want semi-sweet or off-dry, with V 13 you get it dry – take it or leave it.

At the other end of the yeast spectrum is a new strain, approved by the FDA in the US last year, genetically engineered to combine alcoholic fermentation and malolactic (also called secondary) fermentation in one process. How convenient, some might say, but how dangerous, others will find it, for what happens if there is a wine that you don’t want to undergo malolactic fermentation but you have these genetically modified yeast cells swarming in the air all over the cellar? Let’s hope it will never be allowed in this country. I for one will definitely not be using it at Durbanville Hills, of that you can be sure!

• This contribution is extracted, with permision, from the Durbanville Hills May newsletter. Click here for the Durbanville Hills website.