Grape juice concentrate is a controversial topic in winemaking. It’s widely used, but people don’t really like to talk about it, because it sounds a bit like cheating. It’s a brave winemaker who shows journalists this widely used trick of the trade. Normally, it’s kept hidden away.
Most controversial of all is a substance called Mega Purple. This is (supposedly) frequently used in California to add colour to wines, as well as a little sweetness, and has caused quite a stir – perhaps, in part, because of the name. On a recent trip to California I got to see, for the first time, both regular grape juice concentrate, and also Mega Purple.
Grape juice concentrate is made by concentrating unfermented grape juice, typically by boiling it in a partial vacuum, which lowers the boiling point to a temperature where the flavours aren’t completely cooked. It’s then added to wines that have already fermented to dryness at the blending stage.
Many commercial red wines will end up with 4–5 g/litre residual sugar, which will all be from the addition of concentrate. Some have as high as 10 g/litre, which gives them a bit of perceptible sweetness: YellowTail is a famous example of this. A little bit of sugar rounds out the palate and adds to the perception of fruitiness. It also masks harsh tannins and covers over a bit of greenness. Concentrate is typically 68 °Brix (i.e. 68 g sugar in 100 ml, or 680 g/litre sugar): it’s viscous and intensely sweet.
Mega Purple also adds a bit of sweetness, but is mainly used to add colour. It is also grape juice concentrate, but it is made from a teinturier (red fleshed) Vitis vinifera variety called Rubired, which explains its intense colour. Mega Purple is produced by Constellation-owned Canandaigua. It’s expensive, at around $125 a gallon, but very little is needed. The pictures show the effect of diluting a small drop (in the top picture of the two) with water. It doesn’t really smell of much. Typical additions would be 0.2%. There’s also a Mega Red, apparently.
Are these additions to wine evil? Are they cheating? They’re not terribly natural, but because they are derived from grapes, you could argue that for inexpensive commercial styles, there is nothing terribly wrong with them. It is not the same as adding flavourants to wine, for example. Personally, I would rather drink wines that don’t have these additions. But I can understand that these sorts of tools can make cheap wines that non-involved consumers prefer the taste of. If the existence of tasty, accessible, cheap wines helps recruit new wine drinkers, there’s every chance that some of these new drinkers will move on from these entry level wines to more interesting offerings.
I don’t feel like starting a crusade against grape juice concentrate. But I would be happier if fewer winemakers resorted to these tricks. In an ideal world people would make good, inexpensive wines more naturally.