New World Winemaker Blog

On the 28^th of February 2011 I visited Groot Constantia wine estate, South Africa, to investigate how winemaker Boela Gerber plans to make his 2011 Chardonnay – the 2006 version of this wine having earned a place in the top 10 of the 2008 Chardonnay du Monde competition. I arrived just in time to see the grapes arriving in small crates.

Boela adds both 50 ppm SO₂ and Vinozyme skin contact enzyme at the crusher – a significant time apart as not to affect enzyme activity negatively. He does only a very gentle crushing so that a big percentage of whole berries enter the press. He prefers this softer action on the grapes and feels it helps him to minimise phenolic characters.  He uses skin contact enzyme to improve yield and flavour. Enzymes according to him have a softer action on grapes than for instance pressing harder, in terms of improving juice yield. The grapes go through a mash cooler that cools it down to approximately 14 °C. Skin contact is as long as it takes to fill the Bucher press, which is about 4 hours.

His final yield is about 680 L / ton after the addition of some press juice. He adds Novoclair settling enzyme and 6 g/hl PVPP in the press sump before pumping it to the settling tank where he settles for 4 days at 3 – 4°C. The juice then has a NTU of approximately 10 and after racking he increases the NTU to 100 by the back addition of fine lees.

20 % of the wine is then fermented natural in old barrels and the remaining 80% is fermented with Lalvin D 47. He uses liquid ammonia (permitted in South Africa) as a source of nitrogen and Anchorferm as a source of complex nutrients during fermentation. The D 47 fermentation starts in tank and is moved to barrel after 1°B is fermented. He uses Francois Ferrer, Dargaud & Jaegel and Mercury barrels, 50 % new and 50% 2^nd and 3^rd fill. Fermentation lasts approximately 7 days. The wine then stays in barrel on the gross lees until November of each year and he battonages by rolling the barrels. Malolactic fermentation happens naturally and is usually 50 – 60% complete. The wine is then taken out of barrel and treated if necessary with Laffort casein and bentonite. In the years where Boela feels either the wine alcohol is too high or the acidity too low, or both, he blends some of his Chardonnay base wine for sparkling wine production from the same vintage into the final blend to assure a better balanced final product. The wine is then sterile filtered and kept in bottle for 6 – 9 months before release.

The wine retails for £11 – 14 in the UK.

PS: I got the title from a four yearly event that Sonoma Cutrer in California used to host/organise. Does anyone know if this is still happening? Google is not very forthcoming on the topic. As a harvest intern at SC in 1994 I had the pleasure of tasting the left over wines from this event every day. Too bad I did not fully appreciate the quality of what I was drinking at the time…

You may have noticed on wine yeast packets and in the literature that there are mainly two different ways to rehydrate active dried wine yeast. The one procedure is a water only procedure and the other a water juice mixture. The existence of two different procedures on different companies’ yeasts can be quite confusing to winemakers if they would like to standardize their cellar practices. Well the good news is you can. Just pick one that suits you best. The reason why one company – say Lallemand – has the water only rehydration and another company – say Anchor Yeast – has a water/juice rehydration is simply legacy. In the seventies when both companies started to produce and sell wine yeast they just happen to choose different methods and then stuck to it. What is very important is that you follow the method you choose exactly and not take short cuts. Yeast rehydration is extremely important for optimal yeast functionality.

So you might ask why two methods exist in the first place. Well, the best way for me to explain this is that water is what was taken out of the yeast when dried after production, so water is all that’s needed to restore the original cell form. However, water has no osmotic strength, which means that if you do not follow the exact protocol and add juice to the rehydration mixture after 30 minutes, then cell constituents (very small, but very important stuff on the inside of the yeast) can leak out from the high (inside the yeast) to the low (water) osmotic pressure. Simple chemistry. The yeast will lose some or all of its functionality, which could result in fermentation problems. So by adding one third juice to your rehydration mix you add some osmotic pressure – making rehydration more idiot proof. You also provide something for the yeast to start fermenting on right away.

In big co-operative wineries the yeasts for several tanks are rehydrated at the same time. So by the time the winemaker returns to the first tank’s mix – 30 minutes could have passed. In this case the water/juice rehydration would be the safer option.

I don’t have any evidence that one method is more effective that the other if both are followed exactly as prescribed. If anyone out there has experience of one being better than the other then please let me know.

This was a rather boring blog to write. Will have to bring in more humor and opinion in my next attempt. Its useful information though…