WHY TEMPLE BRUER IS MAKING WINE WITHOUT ADDING SO2.
HOW LONG WILL THE PRESERVATIVE FREE AND NO ADDED PRESERVATIVE WINES LAST?
(Just a note here…really important….SO2 is sulphur dioxide…not sulphur… Never, never say there is sulphur in wine… sulphur is a yellow powder and you don’t see that in wine often, do you?)
Two things make wine age…. Oxygen and enzymes. SO2 can react with both of these.
First oxygen!
SO2 is an antioxidant. We all hear about antioxidants and we know they are a ‘good thing’ to have in our diet. We are told that if we drink green tea we will live longer because there are antioxidants in green tea. SO2 is an antioxidant and it makes wine live longer.
SO2 reacts with oxygen removing it from the wine or juice. Remove the oxygen and then the wine lives longer.
Now the enzymes!
You know when you cut an apple or pear, after a while, the cut surface which is exposed to the air goes brown. There are enzymes in the fruit which do this and the same sort of compounds are in wine… working away to make wine go brown when oxygen is present. A very small quantity of SO2 needs to be present in wine to stop this happening. Only 5-10 ppm of SO2 will completely switch off these enzymes.
A note here…ppm is short for parts per million…In Australian dry wine we are allowed to have a maximum of 250ppm total SO2. In certified organic wine we are allowed to have a maximum of 125ppm. In all of our other wines Temple Bruer has a maximum of about 100 ppm. (The EU only allows 100 ppm sulphur dioxide.) And another clarification might be useful here. When the laboratories test for SO2 they quote 2 numbers… one is the ‘total’ which is the larger of the numbers and the other is the ‘free’. Some of the added SO2 stays as SO2… this is the ‘free’ form and the rest of it combines with compounds in the wine to form the ‘bound’ form. The free and bound forms together make up the total.
WHY TEMPLE BRUER IS MAKING WINE WITHOUT ADDING SO2.
With so much going for it, why would any winemaker not want to use SO2? Reason: Some people react to SO2.
How come we can now make wines without SO2?
- Good bottling lines can bottle wine without exposing the wine to oxygen. Temple Bruer uses the Angove’s ‘state of the art’ bottling line
- Screw caps were invented and finally became fashionable. Screw caps prevent oxygen from getting inside the bottle. (corks cannot do this!)
Temple Bruer vintaged in 2006 a Preservative free Cabernet Merlot wine. This wine was made after many many requests over several years by customers. This wine was followed in 2007 by a Preservative free Cabernet Merlot and a Shiraz Malbec. A ‘No added preservative’ Verdelho was also vintaged in 2007.
So why the different descriptions?
There is no domestic legislation at present defining SO2 levels for ‘preservative free’ wine but in some countries SO2 levels must be less than 10 ppm for this appellation. The Australian Wine and Brandy Corporation’s opinion is that this is too high and if there is to be an Australian ruling it should be less than 5 ppm.
Our 2007 ‘No added preservative’ Verdelho had 19 ppm total and zero free SO2 at bottling.
(The reds have zero free and zero total)
(Another really important note here: SO2 levels should always be quoted with a date. We always quote the SO2 at bottling because the level of SO2 in the bottled wine drops every day. We estimate that in 11 months our ‘no added preservative’ Verdelho will be in fact preservative free!)
There clearly is SO2 in the Verdelho, even though none was added at any stage of the winemaking and there isn’t any SO2 in the reds. Why the difference?
SO2 is produced in the fermentation of grape juice or must by yeast. The amounts are variable and sometimes very large (even up to 100 ppm!)
During the fermentation of red wine the fermentation takes place in the presence of the skins. There are many compounds in the skins which can bind with the SO2 produced by the yeast during the fermentation. When 90 to 95 % of the ferment is complete the red grape skins are separated during the pressing process and sent to the Temple Bruer compost heap. Out go the skins with the bound SO2. Thus reds have very little or no SO2.
Whites are made quite differently. The juice is not fermented with the skins. The SO2 produced by the yeast stays in the wine. We will try to find yeast strains which produce less SO2, but this is technically difficult.
HOW LONG WILL THE PRESERVATIVE FREE AND NO ADDED PRESERVATIVE WINES LAST?
SO2 is not the only compound that protects wine from aging. Both red and white wines have naturally occurring antioxidants which are not SO2. Red wines have more. Any stray oxygen molecules which do find there way into a bottle of the Verdelho, at first will be mopped up by the SO2 and then, when the oxygen runs out these other antioxidant molecules will do this job. The red wines have many more naturally occurring antioxidant molecules available to mop up stray oxygen molecules which manage to pass the screw cap barrier. The red wines will live longer. However, remember that all wine will eventually deteriorate. We expect the Temple Bruer ‘preservative free’ red wines to live for about four years and the ‘no added preservative white’ to live comfortably for two.