From Clive Sindelman:
I bought a Groote Post Sauvignon Reserve 2006 at Woolworths in a  Vino-Lok (glass stopper) closure. I thought that it looks great – ie, a lot better  than screw-cap. I detected a few reductive notes on the wine though. Please  give it a review and tell what Grape thinks. Perhaps they have it in cork and screwcap for comparison purposes.

 

Angela Lloyd responds:

First of all, if anyone wants to find out a bit more about the whole concept of ‘reduction’, there’s a good, clear article on the subject by Jamie Goode available online. Elsewhere, Jamie usefully describes a reductive wine as having ‘a slightly acrid, smoky, flinty, rubbery sort of stink to it’.

Anyway, in response to Clive’s observation, I bought a bottle at Woolies in Claremont, kept it in the cellar a couple of days and then chilled it before opening.

The Vino-Lok certainly appears to provide a hermetic seal yet is also easy to remove and replace. This, apart from Clive's view ‘that it looks great ie a lot better than screw-cap.'

First taste (sipped by me alone) didn't reveal any reductive notes but what it did show is a very young sauvignon, still redolent of its fermentation tank with plenty of esters and yeasty/leesy richness vying with more varietally oriented gooseberries and cool climate minerals. It is a rich, concentrated wine albeit with moderate, by today's standards, 13% alcohol. The following day I shared it blind with my Grape colleagues, and again no one mentioned reduced characters. So it was good to read Clive's follow-up comment, when he told us the Groote Post sauvignon ‘has proven to be rather magical in that it lasted and improved in the fridge over six days from opening!'

A lesson to take note of here: not every wine that initially displays reduced characters remains so unpleasant; a bit of oxygen can do wonders, as in Clive's bottle (though it shouldn't take as long as six days!). A good reason not to take too much notice of blind tastings, where the wines may be tasted very quickly and any wine showing reduced characters might be passed over with no later re-taste.

I asked Lukas Wentzel, Groote Post's winemaker for his experience with the Vino-Lok closure, which he has been using since 2004. So far he has found the Sauvignon, which is made to drink well for 7-8 years,  needs more time to develop than when they used cork; he says the 2005 Reserve took about a year to settle, but conversely, the Old Man’s Blend white (sauvignon-chenin blend) was ready earlier. ‘I think the style of wine plays a very big role’, is Wentzel's view.

He agrees with Clive about the initial reductive character of this Woolworths Sauvignon. Other than that, the wine was treated as any other in the range, apart from spending longer on the lees, a procedure that could cause reduction.

I also asked Chris Williams, who bottles his Viognier and a portion of his Syrah under The Foundry label, with screwcap. He responded as follows: ‘When preparing/making a wine that will be bottled under inert closures such as Stelvin or Vino-Lok, far more care has to be taken to ensure that the wine does not contain excess hydrogen sulphide or mercaptans. This this can be done by copper fining and lowering the dose of sulphur dioxide at bottling, but ideally the entire winemaking process needs to be “tightened up” when using these closures, as they accentuate the attributes of the wine, positive or negative. Cork is a very forgiving closure, but far from ideal because of the problems associated with it.'