Last month we had here an interesting discussion on SO in wine, with a very good contribution by ric Texier on the ideas of Jules Chauvet and his work in Beaujolais. In it, the name of the dean of French oenology, Jacques Puisais (BTW - the man who brought the development of taste into the curriculum of French schools), also appeared. Since there was some doubt on the full extent of Chauvet's attitude to SO, I sought comments by Puisais, who is a good friend and a colleague in the International Wine Academy. It took Jacques some time to respond, and it's taken me some time to translate his answer, but here it is finally.
My question (after explaining what WD is) was this: "There's no exact agreement on what Chauvet's attitude to SO was, and as you well know SO is, with yeasts, one of the keys of the 'natural wine' movement. Could you tell us something both on what Chauvet preached and on your own ideas on the subject?"
Puisais' answer:
There are many answers to your question on SO:
1. First of all, I'm glad Jules Chauvet's name has come up. He used to make red wines in Beaujolais with carbonic maceration (CM). CM avoided the laceration of grapes and the action of air, and therefore of oxygen, thus maintaining the must in a reductive atmosphere. This made it possible to use little or no SO.
2. SO was and is used through the combustion of sulfur in wood containers of wine. The air used for this combustion disappears, leaving a reductive atmosphere. It is true that, when the container is filled, the wine absorbs this gas. This absorption is greater if it is filled from the top.
3. SO has several properties:
- It's reductive, protecting wine from the effects of the oxygen in air.
- It's fungistatic, as it opposes the multiplication, not only of yeasts, but also of bacteria: its active part is the free part.
- SO oxidizes by 5 to 15 mg per month, depending on the thermal environment, the size of the containers, etc. So, its concentration diminishes in time.
- In bottle this disappearance is very small, which in particular avoids the re-fermentation of wines with some residual sugar.
4. In fact, while in making red or white wines on their lees (as in the case of muscadet) the intervention of SO is not necessary, for wines with more or less sugar contents it is needed. But thanks to the ease in dosing it, to the use of cold temperatures to favor the sedimentation of lees and to the use of vessels with smooth walls, these additions have become increasingly modest.
5. There have been attempts to ban the use of SO, with the makers and sellers of equipment for thermal treatments (pasteurizing machines and such others) being the most enthusiastic proponents of such a ban. But, fortunately, we have been able to prove:
a- That a thermally treated wine is 'dead', with its 'enzymatic capital' having been destroyed. Therefore its proper bottle aging process becomes blocked.
b- That a 'dead' wine is less well digested, and its physiological features are destroyed.
c- That, as we proved (and that was a decisive fact), grape must produces during its fermentation doses of SO which can reach 60 mg per liter. Therefore, SO is an endogenous component of wine.
d- That, as the research we did with professor [Paul] Jaulmes indicated, no negative effects of SO could be demonstrated, obviously within normal concentrations.
e- That no negative effects on the health of the population can be observed, particularly in the Loire region, where white wines contain SO. (An aunt of mine, who drank Coteaux du Layon wines all her life, died at the age of 101.)
6. What is important is to maintain the reductive capital in wines, that is, to avoid the loss of electrons. Throughout my work in oenology, we have demonstrated, by measuring all rH, pH and Ro (resistivity) how to choose those practices which lead to this situation. That's the essential point, although we also recognize that the use of SO is preferable, in order to maintain a wine's properties, to a negative oxidative evolution.
If SO, unfortunately, is still wrongly used, the responsibility lies with the people who use it. And a wine smelling of SO should be refused. Let's admit that the doses that regulations permit are correct, and in addition they are constantly being lowered. But let's not forget that we can find up to 60 mg of SO, in its combined form, in a wine without any SO having ever been added to the wine!
I would also add that I have found some terroirs where grapes were more sensitive to the effects of air than in other terroirs. Again, it's the environment which is decisive. Therefore, it's by choosing grape varieties with a high reductive power that we'll be able to make progress and also by not forgetting other practices, particularly before fermentation (harvesting, transportation, transfer into fermentation vats) which can weaken the resistance of grapes.
My question (after explaining what WD is) was this: "There's no exact agreement on what Chauvet's attitude to SO was, and as you well know SO is, with yeasts, one of the keys of the 'natural wine' movement. Could you tell us something both on what Chauvet preached and on your own ideas on the subject?"
Puisais' answer:
There are many answers to your question on SO:
1. First of all, I'm glad Jules Chauvet's name has come up. He used to make red wines in Beaujolais with carbonic maceration (CM). CM avoided the laceration of grapes and the action of air, and therefore of oxygen, thus maintaining the must in a reductive atmosphere. This made it possible to use little or no SO.
2. SO was and is used through the combustion of sulfur in wood containers of wine. The air used for this combustion disappears, leaving a reductive atmosphere. It is true that, when the container is filled, the wine absorbs this gas. This absorption is greater if it is filled from the top.
3. SO has several properties:
- It's reductive, protecting wine from the effects of the oxygen in air.
- It's fungistatic, as it opposes the multiplication, not only of yeasts, but also of bacteria: its active part is the free part.
- SO oxidizes by 5 to 15 mg per month, depending on the thermal environment, the size of the containers, etc. So, its concentration diminishes in time.
- In bottle this disappearance is very small, which in particular avoids the re-fermentation of wines with some residual sugar.
4. In fact, while in making red or white wines on their lees (as in the case of muscadet) the intervention of SO is not necessary, for wines with more or less sugar contents it is needed. But thanks to the ease in dosing it, to the use of cold temperatures to favor the sedimentation of lees and to the use of vessels with smooth walls, these additions have become increasingly modest.
5. There have been attempts to ban the use of SO, with the makers and sellers of equipment for thermal treatments (pasteurizing machines and such others) being the most enthusiastic proponents of such a ban. But, fortunately, we have been able to prove:
a- That a thermally treated wine is 'dead', with its 'enzymatic capital' having been destroyed. Therefore its proper bottle aging process becomes blocked.
b- That a 'dead' wine is less well digested, and its physiological features are destroyed.
c- That, as we proved (and that was a decisive fact), grape must produces during its fermentation doses of SO which can reach 60 mg per liter. Therefore, SO is an endogenous component of wine.
d- That, as the research we did with professor [Paul] Jaulmes indicated, no negative effects of SO could be demonstrated, obviously within normal concentrations.
e- That no negative effects on the health of the population can be observed, particularly in the Loire region, where white wines contain SO. (An aunt of mine, who drank Coteaux du Layon wines all her life, died at the age of 101.)
6. What is important is to maintain the reductive capital in wines, that is, to avoid the loss of electrons. Throughout my work in oenology, we have demonstrated, by measuring all rH, pH and Ro (resistivity) how to choose those practices which lead to this situation. That's the essential point, although we also recognize that the use of SO is preferable, in order to maintain a wine's properties, to a negative oxidative evolution.
If SO, unfortunately, is still wrongly used, the responsibility lies with the people who use it. And a wine smelling of SO should be refused. Let's admit that the doses that regulations permit are correct, and in addition they are constantly being lowered. But let's not forget that we can find up to 60 mg of SO, in its combined form, in a wine without any SO having ever been added to the wine!
I would also add that I have found some terroirs where grapes were more sensitive to the effects of air than in other terroirs. Again, it's the environment which is decisive. Therefore, it's by choosing grape varieties with a high reductive power that we'll be able to make progress and also by not forgetting other practices, particularly before fermentation (harvesting, transportation, transfer into fermentation vats) which can weaken the resistance of grapes.