Week 19 (Oct. 28th - Nov. 1st)

Every year 90% of  the new growth needs to be pruned off the vine in order to keep its health in check. This project generally happens in the heart of winter, Jan and Feb, but j-vines like this (ones that aren't cold-tolerant) need to be pruned soon after the first frost, pinned into the ground, and then buried with straw before a true cold sets in. We have therefore begun pruning all of our j-vines and I am patiently learning the art. During pruning one needs to take into account factors like trunk injury, bud positioning, a renewal spur positioning for future years of pruning when determining which shoots/trunks to remove. 

This is the same vine after being pruned. We utilized cane-pruning on this vine, meaning shoots from this year (canes) will be laid down and attached to the fruiting wire in the spring. The alternative method to this is retaining cordons (or extensions of the original trunk) and cutting this year's shoots down to two node "spurs". In either case, this year's growth is saved (either as canes or spurs) because only this wood will produce fruiting shoots next year. The canes/spurs must have substantial wood ripening (periderm/bark formation) in order for the buds to produce viable shoots and clusters. The "primordia" (next years shoots before they begin telescope from the bud) form throughout the entire previous season, therefore it is important that the buds are well exposed to light before they go into dormancy. You can see here that we retained three trunks and five canes. One of these canes (the one that experiences the most winter damage) will be pruned off in the spring, while the other four canes will be attached to the wire, two in each direction. 

This is evidence of winter injury. The pith in the center is dead, along with a wedge of wood. You can tell that this injury happened last winter, as there is a new layer of wood to the exterior of the wedge (this year's growth). I bet that there was a nick in the bark along this section of the trunk which exposed the wood to cold winter air. The circular speckles are also winter injury, representing dead companion cells around what used to be xylem. These cells must have frozen as well, and may even represent years of slight winter injury. 

We need to analyze when malolactic fermentation is complete in all our reds and various whites. MLF is not actually a fermentation, but rather a bacterial inoculation that converts malic acid to lactic acid. This can be beneficial as malic acid is harsh on the palate, where lactic is soft. Also, this process can contribute butterscotch aromas to the wine, which at times is beneficial. Ever notice these buttery notes in your favorite Chardonnay? In order to determine if MF is complete we use a spectrophotomer (light spectrum meter) to measure light absorbency due to concentrations of glucose and fructose, from which malic acid concentrations can be extrapolated. This cuvette contains 100 micro liters of wine and two mL of a buffer solution. We measure how much light is absorbed by this, then add an enzyme and measure it again. The change in asorbance allows us to determine if MLF is complete. Those years of chemistry are finally paying off!