(preemptive defense - I looked under google, and searched here, and didn’t find anything)
Do sulfite levels in wines vary by grape variety significantly? If so, where can I find the relative levels? Or do they vary by soil content a lot? I know organic wines have less because there aren’t any added sulfites, but I’m interested in other things that make sulfite content vary in finished wines.
The main thing that causes sulfites to be in wine is that the vintners put them there as a preservative and to kill off bacteria. They mash the grapes, add some sulfites to kill off the majority of bad stuff in the juice, add their yeast, let it ferment, then give it another dose of sulfites at or around bottling time to stun the yeast into inactivity and kill off the last of the bad stuff.
What Ethilrist said. The main deciding factor within a white or red category is how much the winery added during the making of the wine.
The main variance in the grapes themselves is between white wine grapes and red wine grapes. White wine grapes generally have more sulfites that red wine grapes. Also, in general, more sulfites are added to white wines than red wines to keep them “fresher” longer. A general rule is that white will have more sulfites, but red will have more tannins. The differences between individual grapes are fairly negligible for the most part though.
Also, organic wines can, and often do have added sulfites, and some contain more sulfites than non-organic wines. Sulfites are not part of whether a wine is organic or not. The term organic simply means that no pesticides or growth chemicals were used.
Even a wine labelled sulfite free does in fact, contain sulfites, but the level is low enough that the BATF doesn’t require the statement.
Personally, I always wonder why people are concerned with whether their wine has sulfites or not since most of the food they eat has more sulfites than the wine they will be drinking with dinner. A couple of slices of pizza generally has more sulfites than a couple glasses of wine.