One of the most important jobs a winemaker has during harvest is the decision of when to pick the fruit. Great wine starts with great grapes, makes sense right? The winemaker will go out into the vineyard daily leading up to harvest to taste and inspect the fruit. They are particularly looking for concentration of flavour, ripeness and with reds, skin colour.
Fruit arrives at the winery in hand picked bins or machine harvested in trucks. Either way, the winemaker decides what is immediately going to happen to that fruit and where the fruit will go. For example, on my visit to Isabel Estate, they received gorgeous hand picked Pinot Noir that was kept intact as whole bunches and put into an open top fermenter as is. This decision leads to carbonic maceration, a technique while fermentation starts inside the berries, before any of them are crushed.
This fruit will sit in bins for about a week, before being crushed and pressed into juice. For Sauvignon Blanc, the fruit will arrive on a truck, already determined by the machine harvester, and will go straight into the press. The resulting juice will be transferred to a tank. Rosé will typically have the same process as white wines, but using red grapes. Depending on the winemaker's style of rosé, the colour may just be from a few hours of skin contact after being crushed, or immediately crushed and pressed to limit the colour.
Red grapes usually have an extra step involving the skins. Isabel Estate is known for making incredible Pinot Noir. Once the fruit is received and the decision to either keep the bunches whole or to destem the fruit has been made, the berries are crushed and the must (the juice with the skins and seeds) is transferred to an open top fermenter. In these fermenters, the juice begins to ferment, either with inoculated added yeast or wild indigenous yeast, whilst in contact with the skins. The skins permeate their colour and tannin structure to the juice whilst fermenting. In order to keep the wines even, a cap management plan will be formed by the winemaker.
This may include pump overs, where the juice is taken out from the bottom and returned over the top of the floating skins and pulsed air where a long wand is poked through the cap to the bottom of the tank releasing a burst of air to break up the cap of skins on the top or punch downs, where a disc is used to press the cap down into the fermenting juice breaking up the cap and keeping it wet. Since fermentation produces carbon dioxide the juice and skins are protected from oxidation or fruit flies. Once the winemakers are happy with the amount of skin contact or stage of fermentation the wine is at, the reds will be transferred to a press to get every last drop of, now wine and not juice, out of the skins and remaining berries.
Whites (and some Rosé) will start with juice in a tank or in barrels, direct from the press, and will either be inoculated with the winemaker’s chosen yeast strain (different yeast have different characteristics), or will be left for the wild, or indigenous, yeast to start fermenting with no intervention. Isabel Estate leave all of their Chardonnay juice alone, allowing wild fermentation to occur. The winemakers believe this makes for the best, most complex, Chardonnay, and given all the awards they have won for their Chardonnay, I’d say they are correct. Wild fermentations can be risky and lengthy, however a successful wild fermentation produces stunning wines.
Typically, inoculated yeast will ferment in a week or so. Once the wines reach the desired dryness, meaning the yeast consumed the amount of sugar the winemaker wants, they will add Sulphur to kill the yeast and stop fermentation. On the flip side, Isabel Estate leaves their Chardonnay in barrel until the wine decides to be finished fermenting; this could take months, however the winemakers do not intervene. Minimal intervention is a strong philosophy for the Isabel Estate Chardonnay program.
Ageing wines can happen at different stages of the winemaking process, depending on the wine. If the wines are in barrels, they can be aged with the lees (dead yeast cells), which adds to the palate weight of the wine. Some wines can be aged in bottles.
After fermentation, for both reds and whites, the wines will settle in either tanks or barrels. This step is important for the wines to clarify. There are many different ways to clarify wines. Winemakers may use fining agents, such as bentonite, pea proteins, egg whites (in reds), and others, to bind to the proteins left in the wine that are creating the haze.
Once added, the fining agents and proteins will fall to the bottom of the tank or barrel and a process called racking can be done to siphon the juice off of the remaining solids.
Once the wines are clarified, the wines can be tasted and a blending trial will begin. When fruit arrives at a winery, they will keep different clones, different vineyard blocks, and different fruit all seperate. They will ferment and become their own “batches’ of wine. Once the wines are all finished, the winemakers will sample all of them individually and determine how much of each of the ‘batches’ to blend together. “The sum of the wines are always better than the individual parts alone” - Seb. The complexities of different clones of grapes and different vineyard sites and soil types, add to the complexity of the overall blended product.
Isabel Estate have their own bottling line, which finishes the circle of their ‘grapes to glass’ philosophy. Many wineries do not have a bottling line and need to send their wine in tanker trucks to a bottling facility. Once bottled, the wines will go through a period of “bottle shock”. This typically last for a couple weeks. No intervention is done, they just allow the wines to settle in the bottle before being shipped to sellers.