Dear David:

Thank you for your emailed queries. Thank you also for the time you have obviously invested in thinking over the matters we discussed.

You would be welcome to attend a sweet spot trial at any time. Perhaps the time coordination logistics and the confidentiality aspect would best be addressed by your attending some trials I need to do on my own wines: I have a pinot noir, a cabernet and a sur lies chenin blanc coming up which I'll need to fine-tune in the last half of May. Let me know two or three days which might work for you and I'll pick one to schedule for.

I don't actually think this whole area is a terribly big deal. All wines require fine-tuning just as all other cooking requires the chef, just at the end, to "adjust seasoning." There are hundreds of ways to do this. Even in a single vineyard, single varietal situation, a good winemaker will divide the harvest into sub-lots which are treated differently -- different maturities, different yeasts, different oak -- just to provide blending options later on. Alcohol adjustment is just another example. Scientific enologists often don't take this approach, preferring to adhere to their theoretical notions of purity of varietal character, minimum manipulation and so forth rather than to roll up sleeves and apply technique to an harmonious and focused product. This inattention is evident at the preponderance today of technically unflawed but utterly uninteresting wines on the market.

I don't mean to besmirch the pursuit of scientific investigation. But I do question whether we've really gotten anywhere except to acquire bad habits in our thinking. Science today seems to think itself arrived at certainty rather than engaged in inquiry. In studies of the nature of wine it reveals its inquiry to be barely its infancy, and largely headed in the wrong direction. Sweet spotting exposes two of its key paradigms as demonstrably bankrupt.

The first is the application of the dilute aqueous model, in particular the linear correlation of the concentration in "solution" of wine constituents to "drivers" of sensory aroma and taste intensity such as fruitiness and sweetness. As you'll see, it just doesn't work like that. The analogy to musical tuning as opposed to dissonant noise comes closer to the mark.

The second is the stress on sensory acuity -- supertasters, differing salivary rates, bitterness thresholds, specific anosmic profiles -- as proof that wines are perceived differently by different people. But everybody agrees where the sweet spots are and also how they characterize themselves. Moreover, in between them there is general agreement that the wines are disharmonious -- more astringent, less sweet, less focused. We really have no idea what's going on, but these effects are clear.

The strong agreement on what's harmonious and what's dissonant is good news for winemakers. Like a musician needs to believe that the emotional communication power of music is universal, the winemaker needs to know that tuned up is tuned up for everybody. Like any other cooks, winemakers need to adjust the sauce with confidence.

Alcohol sweet spotting has fascinating special value as a probe into wine's true nature simply because it is so simple to adjust and because it has little flavor of its own. Its relative purity allows it to demonstrate with greater clarity than other blending techniques the nonlinearity and universality of wine balancing. Conversely, from an artistic standpoint, it is comparatively mundane.

When we do a sweet spot trial, we reduce the original wine (via our recombinatory reverse osmosis permeate distillation process) to somewhere below where we think we want to end up. Then we blend the original wine in, or we bump the alcohol back up by adding back high proof alcohol, either way laying out fifteen or twenty wines which are different only in their alcohol content and separated by 0.1% alcohol. For example, we might take a 15.0% chardonnay and look at the range of 12.5% to 14.5%, 21 wines lined up: 12.5, 12.6, 12.7...14.4, 14.5%. You'd think the wines would just gradually get better, then worse. That never happens. There are marked differences in "harmoniousness." You see maybe one wine in siz that is focused. The rest are astringent and unbalanced. Kind of like the unfocused, defect-free wines you usually see on the market. The differences are pretty obvious.

Could an expert pick out such wines? Well, perhaps on occasion a zinfandel possessing ripe, round tannins or a viognier with well-developed honeysuckle aromas but without the expected hotness might lead one to speculate that the technique had been employed.

As for its gentleness, It actually involves very little processing and by any standard of wine treatment, that is if one were to compare the effect of, say, pad filtration, cold stabilization, or bentonite or egg white fining, it is certainly less deleterious to flavor than these normal and accepted treatments which attract less attention.

There doesn't seem to be any way to predict where the sweet spot will show up.

On the other hand, we do have names for the styles we often see. We talk about the "jammy, in-yo-face CaliforniaZin" vs the "SuperTuscan" sytle the same wine can exhibit at lower alcohol: less forward fruit but more refinement and length. In Chardonnay we often see the "California Montrachet," the "Mersault style" and the "Faux Chablis style."

It is also predictable that high alcohol wines will be hot, bitter, and low in fruity aromas, while low alcohol wines tend to be thin, salty, and possessing what we call acid-based astringency. And we usually see these same characteristics in the wines one tenth of a percent above and below the sweet spots.

Your instinct about chaptalization in Europe is, I think, correct. Proper harmonious balance isn't normally achieved. That's OK, though. They just have to find another means to fine tune the wine.

For a great reference on the non-connectedness of brix/baume/oechle/sugar content vs true maturity, get:

Australian Journal of Grape and Wine Research, Vol 6, No. 2 Proceedings of Symposium on Reproductive Biology in Grapevines. This is sort of my bible on this topic.

Relating to ageing, empirically we often see that the same wine aged at different alcohols ages differently. Experiments on Zinfandel by Carole Shelton and at Murphy Goode on Merlot showed that higher alcohol wines develop more raisiny aromas. We don't know why. There may be a relation to the considerable suppression of dialectic constant at higher alcohol, but the effects are larger than one would expect from a shift to 14.5% to 13.5% as in Carole's trials. Colloids are a lot less stable at higher alcohol, and this may also relate.

Regarding MOx, it is clear from large numbers of trials that wines properly structured with oxygen have considerably more longevity than their conventionally made counterparts, which tend to dry out, precipitate structure, brown, and push aromas of veggies, oak and Brett while the MOx'd counterparts are still holding together well.

Hope this helps. Let me know.

PS I'm still looking around for that old Wine and Food Companion on pairing wine and oysters -- must be buried in the garage somewhere, but I'll keep you in mind to receive a copy whenever it gets unearthed.]