Double, double toil and...

...trouble.  A stuck fermentation spells big trouble for a winemaker, as unfermented  °Brix can be a source of food for unwanted wine microbes which can spoil a whole lot of wine.  Stuck fermentations can occur for many reasons; an incorrect initial yeast selection; competition from other microbes (pediococcus, lactobacillus etc.); high fermentation temperatures. The best way to deal with a stuck fermentation is by avoiding this undesirable turn of events in the first place because restarting one involves a lot of work. 
Down in the bowels of TWWIAGE is a bubbling cauldron of 2013 Cabernet Sauvignon.  A lot of fiddly steps are being followed by the production team to get this particular fermentation going again, but restarting a stuck fermentation essentially involves a new yeast selection and a lot of granulated sugar...and perhaps throwing in the odd "eye of newt" and "toe of frog" for good measure.  The colour in the above photograph is off a little, in reality the fist-sized bubbles are a wonderful blue-purple.  Bubble on little yeasties!