In a recent interview, the question came up "I know you've talked about how the German theory of wine doesn't really apply to red wine, but I'm curious to know a bit more of the why behind that. What about red wine makes cold stabilization and sterile filtration undesirable, and why isn't white wine affected in the same way? I assume it's connected to the larger, more complicated molecules in red wine, but I'm curious about the mechanics." I thought it was a good question which others might be interested in hearing about, as it probes the true nature of wine.
First I'll mention that the line isn't really between red and white, but between structured and unstructured wines. Many whites (such as Faux Chablis, or method champenoise champagnes) have a lot of colloidally suspended material.But we know the idea of macromolecular structure must be correct for all red wine, because the anthocyanins which give red wine its color are not very soluble in a 13% alcohol: 87% water solution. The maximum you can get to dissolve results in a light pink solution. This puzzled enologists for many years since Ribereau-Gayon first pointed it out in the '60's.
We now know that the color molecules aren't dissolved at all -- they're contained in tiny pieces of goodge we call colloids, which are sometimes almost as big as a bacterial cell. If we disrupt these particles with sterile filtration or drag them down to the tank bottom during cold stabilization, we lose texture but also we lose the aromatic integration properties they impart to wine. I believe this integrative phenomenon is central to wine's ability to provide a soulful, visceral experience.
In a simple solution, these problems don't exist. The precipitation of bitartrate or the filtration of bacteria doesn't effect the concentration or aromatic expression of, say, the terpenes which give riesling its fruity, flowery flavors. But neither do these wines prompt the same mysterious soulfulness. Their focused fruit can be lip-smackin' delicious, but people who say a wine's first duty is to be red are looking for something more substantial than focused fruitiness. This is the same reason bisque is generally preferred over consommé.