This post continues the discussion started last Monday.

After the red wine completes secondary fermentation (or malolactic fermentation), the winemaker has the choice of whether to add SO2 to the wine. SO2 prevents microbial activity and oxidation of the wine. The vast majority of winemakers do choose to “sulfur” the wine, I among them. While there are winemakers who choose to go without SO2, it’s taking a big risk to the wine’s stability. I’ve tasting a number of non-sulfured wines, and they have done nothing to change my opinion or practice. Even most winemakers that call themselves “natural” use SO2 routinely in their winemaking.

As bottling approaches, the winemaker has the option of fining his wine. Fining involves the addition of a protein-based product, usually egg whites or gelatin, to reduce the tannins in the wine. Again, since the products used are more natural, you can argue whether fining renders a product less “natural” or not. At any rate, I try to avoid fining, since it often strips away fruit flavors along with the tannins. I also like tannin more than most people, so I am less likely to find a wine too tannic. However, for some wines (e.g., Petite Sirah) some fining is usually helpful.

A winemaker may also choose to add tannins to a wine that is tannin-deficient. I’ve only done this once, but for that one time where the tannins were lacking, the result was good. I would do it again in the right circumstances. The added tannins are usually extracted from grapes, so you once again can argue whether this intervention makes the wine any less “natural”.

The last intervention that I’ll mention is filtering. This is done shortly before bottling, and removes any microbes from the wine. A filtered wine is a stable wine. But the converse, that an unfiltered wine is an unstable one, is not necessarily true. Many wines are “clean” without the need for filtration. I personally will filter if there’s any doubt, but if the wine is tested and is found to be clean (there are testing labs that will perform these analyses), there’s no reason to filter. Many winemakers feel that filtration strips flavors from the wine, but I tend to doubt that. When I’ve tasted the same wine pre- and post-filtration, I haven’t been able to tell a difference. And the flavor components in wine are much smaller than the filter pores, so I’m not sure how those flavors could get striped out.

There is a phenomenon called “bottle shock”. This occurs after bottling and can result in the wine being “dumb” or even having weird off-flavors for a period of time. I suspect that filtration may be a contributing cause to bottle shock, but really can’t say that with any degree of certainly.

There are many, many other “interventions” that a winemaker can employ, some of them involving fairly expensive equipment that is really only available to large wineries. Many of these interventions are intended to produce a “squeaky clean” product for mass consumption. Since I don’t have experience with them, I will not discuss them at any length. However, I do believe that trying to make a wine “squeaky clean” generally results in a more commercial and, to my mind, inferior product.

The bottom line is that all of the interventions I’ve discussed above are appropriate for a particular wine. I wouldn’t rule any of them out out of hand. But my bias is against using many of the interventions I’ve discussed. If, for example, a wine is particularly tannic, then fining is in order. But close calls should be resolved against intervention.

I’m not sure where this places me in the discussion of “natural” wines. In theory, I believe that if an intervention helps a wine, it should be employed. In practice, I think I probably use fewer interventions than many winemakers, which maybe nudges me a little towards the “natural” camp. But my real opinion is that the discussion of “natural” wines is a simplistic gloss over what is really a very complex subject.

There’s been a lot of press lately on the subject of “natural” wines. I really don’t like the term for a couple of reasons. First, it’s not very well defined. There are a number of interventions (or manipulations) that a winemaker can make, and whether any particular intervention is “natural” or not is often a matter of opinion. But my main criticism of “natural wines”, though, is that it’s basically a put-down of non-“natural wines”. Wines that are made with more rather than less manipulation are not for that reason inferior. There are many wines that are made with little manipulation, and are bad, and others made with considerable manipulation, and are good.

That said, my basic rule of thumb is that unless a contemplated manipulation will greatly improve the wine (not marginally improve it), don’t do it. There are many times that I’ve done a bench trial and felt that some intervention would improve the wine, but later been disappointed when I concluded I would have been better off leaving well enough alone.

That said, there are a number of things that winemakers do to their wines that would qualify as interventions. It is only by understanding what those interventions are, and what they do to the wine, that someone can form any sort of informed opinion about whether wines should be “natural” or something else.

So let’s start with the grapes as they come to the crusher. (Since I don’t make white wines, I’ll limit this discussion to reds, though some of what I say about reds applies to whites as well.) There are three things that can be done at that point to the must. First, you can add some sort of tannin, usually oak powder. Oak powder results in a wine that has much more color and body. This to me is a no-brainer. I use oak powder routinely. If I made a very light wine (e.g., Pinot Noir), I might pass on the oak powder to preserve a paler color, but I don’t make Pinot Noir.

The second thing you can add is SO2 (sulfur dioxide). This addition will kill off microbes that come in from the vineyard with the grapes. Since I don’t want a “natural” fermentation, I add SO2 routinely. However, this point really turns on whether you want a fermentation with or without using commercial yeasts. I always use commercial yeasts because of the risk that allowing the yeasts in the environment to ferment the grapes may result in some unpleasant results. Commercial yeasts give a more predictable result, and more control over the winemaking process. That said, if a winemaker chooses to go the “natural” route, I can hardly fault him.

The third thing you can add at the crusher, or shortly thereafter, is tartaric acid. This is the acid that occurs naturally in the grapes. If the amount of tartaric in grapes is low, the wine will be flabby and overly soft. In California, this is a common problem, and should be rectified by the addition of tartaric acid.

Once the fermentation is done, a winemaker has the option of treating the wine with micro-oxygenation. This process involves the injection of tiny oxygen bubbles into the wine at a controlled rate. Micro-oxygenation stabilizes color and softens tannins. I use it on big, tannic wines, such as Petite Sirah. I don’t use it on lighter bodied wines, such as Montepulciano. Since this process doesn’t involve adding any chemicals to the wine, you can argue whether its use compromises a wine’s being “natural”.

More on this subject next Monday.