I have learned so much from this discussion and am very grateful for it.
I came in late and have been hesitant to join in, partly because there were so many interesting points of contact that it was hard to choose where to begin, and partly because I did not want to jump back to an earlier point in a vigorous discussion.
some of our practices are unconventional or atypical and I thought that they might be of interest. I recognize that the wines that we make are not to everyone's taste and that they may well span a rather wide spectrum of quality. Nonetheless, my sense is that since about 2005, none of the criticisms leveled against the wines have been because of spoilage or other factors that might have been mitigated by other practices or regimes in the use of SO2. for that reason, whether the wines are admired or not, I thought thatese notes my be interesting to this group.
1. HOW WE INTRODUCE SULFUR INTO OUR WINES
we use exclusively dilute sulfurous acid in a 6% concentration. we calculate and measure everything on a PPM (grams per kiloliter) basis; to minimize my own confusion I will refer to our practices in these units.
2. THE USE OF SULFUR BEFORE FERMENTATION
we make two kinds of distinctions at the moment of fruit reception:
a) is the wine destined to be exposed to oxygen in its elevage, or do we intend to preserve freshnesss?
b) do we want to discourage malo-lactic fermentation?
these two are often but not always the same question. we sometimes allow the wine to go through malo but want to discourage oxidation.
if we want to discourage either or both oxidation and malo, we add about 50 ppm at the earliest practical moment. for wines made from juice, this addition is made in the press pan or in the settling vessel. I don't think that we have ever added so2 to wines made from fruit as opposed to juice.
examples of wines that get 50 pmm: naucratis, LSB.
examples of white wines that do not: sylphs, gemella.
one might ask whether presumed microbial load does not also enter into our thinking. the simple answer is: no. first: we never see fruit with any levels of inocculum that worry us (with the long island fruit that goes into the redhook wines, this is not always the case). with some wines we want to encourage the proliferation of what comes in on the grapes (oro puro late harvest wine, the prince); with others, we just don't worry (hudson syrah).
to my recollection, we have never used any pre-fermentation sulfur on wine made from: crushed fruit, whole berry fruit, whole clusters. all of the wines that we make from fruit undergo various periods of maceration-- from 4 to 11 days. we use cold to delay the onset of or the explosion of fermentation. we do not use sulfur during this phase.
3. THE USE OF SULFUR DURING FERMENTATION
we never inocculate with any purchased or cultured microbes. we rely on what is living at the winery and in all of our equipment and on the grapes.
in general, we add no sulfur during the fermentation of any wine-- though some of the wines that we pointed to above will have added sulfur in them during fermentation.
exceptions: very seldom, we will notice a very high degree of aromas associated with bacteria and or non-saccharomyces yeast at the beginning of fermentation. if we become alarmed, we try to beat down the microbes producing these aromas by encouraging the saccharomyces cerevisiae, and we do this by heating the fermentation to about 85 F as quickly as possible. we rarely but sometimes add 15-30 ppm at this point to try to discourage the non-saccharomyces cerevisiaemicrobes, in the belief that saccharomyces cerevisiae, especially strains descended from commercial yeast, will be be more resistant to the added sulfur.
we are not sure that this has any beneficial effect. it is one of those things that we probably do in order to feel responsible and dilligent.
some fermentations slow down precipitously before they finish. we often hit these with 15 ppm at about 1-0.5% residual sugar. we believe that this might discourage unfriendly microbes and in any case will help protect the wine against premature oxidation during a longer fermentation.
since 2005, all of our syrah has been 100% whole cluster. during 2006, we experimented with pre-fermentation "maceration" of whole clusters un-crushed and un-sulfured. all of the wine made from this fruit spoiled: too many non-saccharomyces cerevisiae microbes grew all over the exposed fruit during the maceration and saccharomyces cerevisiae yeasts could never regain control of the fementation. since then, we always do pigeage on whole-cluster fruit as we fill the fermentation vessels. the pigeage ensures that all of the fruit, usually even at the top surface of the vessel, is completely immersed in juice. this seems to be sufficient to prevent unwanted population explosions. we do not add any sulfur at this point and have had no difficulties since we began pigeage.
4. THE USE OF SULFUR DURING ELEVAGE, YEAR 1
we repeat the same distinction from phase 1 above.
if the wine is destined to be exposed to oxygen, it gets no added sulfur at this point. in general, this means that no wines made from fruit as opposed to juice (all red wines, the prince) get any sulfur during elevage. in general, all chardonnays are allowed to go through malo and to soak up oxygen, so they get no sulfur. some of the verdelhos get moderate amounts of sulfur during elevage to moderate oxygen uptake and discourage malo.
The wines that we want to preserve from oxygen get hit with a lot of sulfur. I began following this program after I analyzed some gruners that I admired very much (fx pichler, knoll) and found that they had 50 ppm free and up to 200 ppm total, even 2 years after bottling. our wines which are intended for freshness wines will be bottled with 24-50 ppm free and 100-200 total.
I should mention that even though we use sulfur to try to inhibit or moderate malo, we do not have anything close to complete success. the high pH riquewihr, made from gewurz, seems to go all the way through malo even with free so2 levels between 20 and 50. I can't say that we have ever ensured that it stayed at 50 free from juice to bottling, so perhaps malo is occurring when the free level is below some threshhold; or, alternatively, perhaps if you don't throttle back the organisms from the very beginning, maybe malo becomes inevitable even if you add a lot of sulfur later.
5. THE USE OF SULFUR DURING ELEVAGE, YEAR 2
some wines have 2 years of elevage. these wines we begin to monitor very carefully around may of their second year. At this point, barrels which have gone untopped since the first of the year will be topped, and some will get their first sulfur additions. This will typically be about 40 ppm. Wines that seem sound get no sulfur. Triggers for sulfur addition are: aldehydes, VA, tiredness from oxidation.
some wines typically go through their whole 18-24 months of elevage without any sulfur addition at all (babylon, prince-- though the prince is sometimes bottled after only about 12 months).
6. THE USE OF SULFUR FOR REMEDIATION
because we top so seldom, some barrels of both red and white wine develop higher levels of aldehydes than we would like. we attack these with sulfur additions, usually adding an initial 20 pmm and sometimes up to a toal of 100 ppm to titrate out the aldehydes and restore some level of freshness. many different principles lead to this practice-- one might wonder, why not add more moderate amounts of sulfur at more regular levels, and top, rather than be required to beat back aldehydes later. in short, the reasoning is that we gain from exposure to oxygen and limiting sulfur inputs-- it just that sometimes some barrels get away from us while we are waiting for good things to happen. also, in some wines, we are looking for VA to develop to a certain level (choepheroi, sylphs, scheria, iseult). while waiting for this, we leave the wine unsulfured and so might get more aldehydes than we want.
7. SULFUR AT BOTTLING
We try to bring all wines to 24 ppm free sulfur on the morning of their bottling. very seldom do some wines go to bottle with more than this; that result is always inadvertent. very often with wines go to bottle with less. analyses of some of our bottled whites show levels between 2 and 20 ppm free. even the wines that previously got no S02 during their elevage get sulfur now. this is partly superstition.
the other part is the following belief: for the most part, we bottle the wines when we think that they are very good to drink. we use 24 ppm as means of preserving them in their pre-bottling state for about 2 years. this is somewhere between a wish and a guess. we also think that that the sulfur gives focus and underlines intensity in the more floral whites (naucratis). some few of the wines actually seem fragile at bottling (glos, nereides)-- for these, the 24 ppm is supposed to buttress them and allow them to age a little longer without falling apart or developing more VA.
even this last could be superstition: we have no evidence from our own practice that sulfur as we use it is a microbicide. at most, it stuns or slows down certain microbes.
in sum, we hardly use sulfur as an aid in controlling spoilage organims or unwanted microbes of any kind-- with the exception of malolactic bacteria. in general, we rely on the vigor of saccharomyces cerevisiae, and the internal competition of a highly diverse, relatively low pH (4.05 and lower) bioliogical system to keep any unwanted population in check. we do use sulfur to limit oxygen uptake, to buffer wines or juice against oxygen, to prevent formation of aldehydes, to break down aldehydes once they have formed. In advance of bottling, we use sulfur to buffer the wine against oyxygen and thereby to attempt to preserve it longer in its pre-bottling state.