In Australian white wines, what’s the difference between SSB and SBS?

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Dear Dr. Vinny,
In Australian white wines, what’s the difference between SSB and SBS?
—Terry, Victoria, Australia
Dear Terry,
SSB refers to a Sémillon–Sauvignon Blanc blend, while SBS is a Sauvignon Blanc–Sémillon blend. I know it seems like I just wrote the same thing , but as with ingredients in all kinds of things, the prominent ingredient is listed first, so an SSB will have more Sémillon than Sauvignon Blanc, and an SBS will have more Sauvignon Blanc than Sémillon.
SSB and SBS are useful abbreviations, but they’re not common terms. I’ve mostly seen them used to refer to white blends from Western Australia, and not many of those wines are exported.
Sémillon and Sauvignon Blanc are two white wines grapes that are often blended together, as in the white wines of Bordeaux. Sauvignon Blanc is more aromatic, juicy and intensely flavored, but Sémillon’s richer body, lower acidity and slightly savory note of lanolin (think of the smell of wool sweaters) or beeswax adds a lovely complement to Sauvignon Blanc. They balance each other out really well, but knowing how the acronym works, I’d expect an SBS to be lighter and juicier than an SSB.
—Dr. Vinny