...the true expression of French terroir, the untranslatable concept encompassing...
"It's not untranslatable" I thought to myself. "We might not have a word for it in English, but it's not untranslatable." Then I stopped, struck by the absurdity of what I'd just thought. If there isn't a word for something, then of course it's untranslatable.
Or is it? There are things which are untranslatable – concepts we simply do not have – but terroir, even if it's not common enough in English-speaking thought to have its own word, is still expressible as a concept. As the sentence continues:
...not just the soil in which the vines grow but also the natural, geological climatic and cultural elements associated with it.
There you are, that's terroir in English. I've even read elsewhere that:
PDO (Protected Designation of Origin) is "EU for terroir".
But I expect that as long as it continues to be a concept most closely associated with wine, we won't develop a word for it. They've probably got one in Australia though!