Ch. 18: Red Winemaking Flashcards
Anthocyanins
The source of color in young, red wines. They are not very stable on their own, and become more stable when combined with tannins, leading to greater color stability.
Oxygen faclitates this reaction, and therefore, winemaking processes that encourage the gentle oxygenation of the wine (e.g. micro-oxygenation or barrel aging) can help promote color stability.
Anthocyanin-tannin compounds change more slowly over time than antocyanin compounds (wine becomes paler and changes from ruby to garnet to brown).
Maceration
Before, during, after fermentation
Before fermentation, the goal of maceration is to extract color and flavor, without extracting tannins. Anthocyanins are more soluble in the must, while tannins are more soluble in alcohol.
During fermentation, the skins are mixed with the juice to manage the cap, the layer of grapes skins that rise to the top of the juice. There are many reasons for cap management. It prevents bacteria from forming on a dry cap and converting alcohol to acetic acid. It aerates the must, helping to avoid reductive sulfur compounds. It helps distribute heat that forms during fermentation which is important for temperature control. Colors are extracted more at the beginning of fermentation, tannins at the end. The techniques, timing, and frequency of cap management has a large influence on the final wine style. Temperature also has a role, with warmer fermentations extracting more than cooler fermentations.
Post-fermentation is optional. Can last from a few days to a few weeks. The aim is to extract more tannins and improve tannin stucture and texture, and thus, the wine’s aging potential. Due to the time and cost, it is only used for premium or super premuim, very good to outstanding wines that are meant for aging.
Cold soaking
Pre-fementation maceration. The juice is chilled to under 50F in order to prevent oxygenation, spoilage, and spontaneous fermentation. It typically lasts around 3-7 days and uses punching down or pumping over to mix the skins with the juice and aid with extraction.
Cold soaking is gentle and suitable for premium wines. It is commonly used on Pinot Noir to promote color intensity because Pinot has a low level of anthocyanins. It is used to promote color extraction without risk of extracting high level of tannin.
Costs include energy to chill the wine and extra time, so is usually not for high-volume, inexpensive wines.
Flash détente
A form of pre-fermentation maceration using heat. Its aim is to extract high levels of anthocyanins and flavors quickly. Destemmed grapes are quickly heated to around 190F and then rapidly cooled under a vaccuum. The process lasts around 2 minutes and bursts the cells in the grape skins, allowing very rapid extraction of anthocyanins and flavors.
The short time at high temperatures limits cooked flavors from developing. The vaccuum system is expensive and therefore, tends to be used for high-volume wines. This technique intensifies the fruitiness of the wine. It can also be used for Smoke Taint, and is beneficial for wines with grey rot.
Thermovinification
A form of pre-fermentation maceration using heat. Its aim is to extract high levels of anthocyanins and flavors quickly. This involves heating the must to around 120 - 140F and macerating with the skins from minutes to several hours. The higher the temperature, the shorter the maceration.
This technique intensifies the fruitiness of the wine. It can also be beneficial for wines with grey rot.
Cap management
The process of mixing the grape skins with the must during fermentation. There are many reasons for cap management. It prevents bacteria from forming on a dry cap and converting alcohol to acetic acid. It aerates the must, helping to avoid reductive sulfur compounds. It helps distribute heat that forms during fermentation which is important for temperature control. Colors are extracted more at the beginning of fermentation, tannins at the end. The techniques, timing, and frequency of cap management has a large influence on the final wine style.
Temperature also has a role, with warmer fermentations extracting more than cooler fermentations. If a winemaker wanted to reduce tannin extraction, they could cool the wine near the end, when tannins are most likely to be extracted.
Punching down
A cap management technique. A plunger is used to push the grape skins into the liquid. It can either be by hand, or mechanized. By hand is gentler and more labor intensive, and thereforme better suited to low-volume premium wines.
Pigeage is the French term.
Pumping over
A cap management technique. About 1/3 to 1/2 of the juice/wine is taken from the bottom of the vessel and sprayed over the cap. The liquid extracts color, tannins, and flavors from the cap as it passes through. The extraction is very gentle and usually also requires punching down or rack and return to extract enough color, flavor, and tannin.
It can be carried out either aerobically or anaerobically, and is commonly used on all black varietiys, for wines at all price points and qualities, and is suitable for use on large vessels. In modern wineries, the process is automated, so there is less labor costs.
Remontage is the French term.
Rack & return
A cap management technique similar to pumping over, but the juice is pumped from one vessel to another vessel. So the juice is moved from one vessel to another with the skins remaining in the on the original vessel, and then pumped through the new vessel into the top of the original, spraying the juice on top of the skins. It is more extractive than pouring over or punching down, and can only be used 1-3 times during fermentation along with punching down and pumping over.
It is commonly used for red wines where med-high levels of flavor, color, and tannin are desired (Cab Sauv., Syrah).
It cannot be fully automated and requires labor and clean vessels to be available.
French name: delestage
Ganimede tanks
Cap management technique. Bubble CO2 (or oxygen, if desired), up through the must/wine. Pressure build up under the cap until it bursts. This technique breaks up the cap quickly and is extractive, good for producing wines with med-high tannins, flavor, and color, like Cab Sauv. and Syrah.
It is a new technique and is increasingly common because it can be fully automated and is less labor intensive than rack and return - another extractive cap management technique.
Rotary fermenters
A cap management technique. Horizontal, closed, stainless steel tanks that rotate and have internal blades that break up the cap and mix the wine with the skins.
They are very effective at extracting and best suited to wines med-high color, tannin, and flavor, such as Cab Sauv. or Syrah. The rotation is automated and labor requirements are low.
It is common for high-volume, inexpensive or mid-priced wines with acceptable to good quality. They are expensive so large quantities of wine need to be fermented in them to make them cost-effective.
Saignée (in the context of red wines)
Some of the juice is drawn off just after crushing and before fermentation, concentrating the must and thereby, increasing levels of color, flavors and tannins.
This lowers the volume of the red wine left in the tank, which has implications for the price.
The juice that is removed can be used for rose as it is light in color, flavor and tannins.
Co-fermentation
Fermenting different grape varieties together in the same vessel. It commonly refers to the practice of fermenting a small proportion of white wine (5% or so), within a red fermentation. Phenolics in the white grapes can bind with anthocyanins, increasing color intensity and stability. The white grapes can also contribute aroma compounds (terpenes in Viognier give floral and fruity characteristics).
This technique originated in Cote Rotie, particularly famous for the co-fermentation of Viognier and Syrah.
Whole berry/bunch fermentation
Winemakers can choose to use whole bunches of grapes or whole destemmed grapes, and can use either entirely uncrushed fruit, or a propotion of uncrushed fruit in a crushed fruit fermentation.
Whole bunches must be hand harvested, and it is important that the stems are ripe so as not to impart bitter tannins or unpleasant green flavors. Ripe stems can impart spicy or herbal flavors, and add some tannins.
The goal of whole berry/bunch fermentation is to create an oxygen-free environment for the uncrushed grapes. This leads to anaerobic fermentation, where some of the sugar inside the grapes is converted to alcohol, without any yeast. Malic acid withing the grapes is also broken down to create ethanol, lowering acidity and raising the pH of the must/wine. Glycerol levels increase, which can add texture. A range of distinctive aromas and flavors are created inside the grape, including cinnamon, kirsh, banana, an bubble gum.
There are 3 forms of whole berry/bunch fermentation: Carbonic Maceration, Semi-Carbonic Maceration, and whole-berries with crushed fruit.
Carbonic maceration
A form of whole bunch fermentation. Whole bunches of uncrushed grapes are placed into vessels filled with CO2 to remove all oxygen. This causes intercellular fermentation to start, producing about 2% alcohol. At this point, grapes can be crushed, or they naturally start to split and release their juice. The juice is drained and grapes pressed at this stage to ferment off of the skins.
THis method extracts color, but little tannin. These wines are defined by their fruity, low tannin profile and are best drunk within a year after harvest. The flavors are distinct (cinnamon, banana, kirsch) but not complex. It tends to be used fo acceptable or good, inexpensive and mid-priced wines.
Beaujolais Nouveau is a classic example of Carbonic Maceration.
