So what is wine made of?

For those of us immersed in winemaking, a surprising question relates to the tasting notes we often use on back labels, along the lines of 'So, if the wine has aromas of blackcurrant and chocolate, how do you get those in there?' So the first point to make, is that wine is made from grapes. Just grapes, and if there is anything else used, it can only be from a list of approved additives and processing aids, which is authorised by Food Standards Australia New Zealand (search for "standard 4.5.1"). Blackcurrant and chocolate are not on the list, those flavours come from the grapes, or perhaps from the oak barrels the wine is matured in. Most wines involve a few additions, typically yeast (although the indigenous or wild yeast may be used in place of an added yeast) sulphur dioxide and tartaric acid. It is worth keeping in mind (and, I think, paraphrasing Pasteur) that nature, left to itself, will turn grapes into vinegar, so if you want to make wine you need to intervene somewhat. Next, lets look at the list of allowed additives and then the list of processing aids.