With harvest in full swing, and all of the complications of the drought, we are now seeing a new aspect of Harvest 2015. Raisins. They are everywhere. It’s like a night of the living dead. But instead of the dead, it’s raisins. You may be wondering why you should care, or how raisins greatly impact the wine making process. I will tell you dear reader.
Here’s the background: California is in a huge drought. (I’m sure you are saying ‘duh’ right about now.) There is no water. (‘Really?’) So, irrigation has been a huge problem. There has also been a high incidence of “hens and chicks” this year. “Hens and chicks” is where berries in the same cluster develop at different rates. Depending on how developmentally different the berries are, some can be green while some can be raisins. Taken together, the result is having to wait quite a bit of time for the entire cluster to reach a high enough Brix to harvest. Despite the heat, there are so many green berries, there has to be numerous raisins within the same cluster to raise the average Brix for that cluster.
One may ask, if the Brix is spot on in the sugar sample pre-harvest, what is the problem? Well, the problem is raisins are very sneaky. Due to the heavy dessication of raisins, and thus concentration of sugars, it takes a while for the sugars to dissolve into the must and the juice to reach the true Brix level. (This is particularly for red wines). For example, say I cluster sampled a Pinot Noir vineyard and got a Brix of 26.5. I then harvested the fruit, destemmed it, maybe slightly crushed it, and tossed it into a tank. Well, over the course of a 3 to 5 day cold soak (letting the grapes sit at 50F for extraction of color and tannins), with raisins the Brix could increase up to 27.5 or even 28 Brix. This dramatically increases my final potential alcohol which, if I had chosen a yeast with a low alcohol tolerance or am relying on a native ferment, could cause the fermentation to stick.
A stuck fermentation is problematic. The remaining unfermented sugar could be used by other organisms to grow and spoil the wine. Also, the existing yeast could spontaneously restart the stopped fermentation and produce off characteristics of their own. “Dry” wine, with no fermentable sugar, is the safest situation for the wine to be in. So, you can see how sneaky raisins leaking extra sugar could lead to problems down the road.
Another side effect of raisins in the must is the taste of raisins. I know it seems overly basic, but raisins taste like raisins. If you are making a wine that is not meant to have characteristics of overripe fruit and raisins, then you don’t want raisins. Raisin flavors are overpowering and a small percentage can easily affect the organoleptic properties of the entire batch. Personally, I don’t mind raisins. I think they add a sweet, savory character that enhances my preferred wine making style. However, not everyone is of my mindset. If you like those attributes, this is your season! 2015 wines will be your vintage! If you don’t, I suggest drinking any other vintage.
Nonetheless, I suggest trying a few different varietals and styles of varietals from this vintage to get an idea of how raisins affect wine making decisions and how wine makers have handled the season. I am intrigued already!